Methods For Producing Metal Powders And Metal Masterbatches

- Nanoscale Powders, LLC

A method for producing a metal powder that combines molten reducing metal and metal halide in a space that is substantially free of oxygen and water, wherein the molten reducing metal is sodium and/or potassium, or aluminum (or magnesium or titanium) and is present in a stoichiometric excess to the metal halide which is a solid or liquid, thereby producing metal particles and salt, removing unreacted reducing metal, optionally removing the salt, and recovering the metal powder, is described. A method for producing a metal masterbatch wherein the molten reducing metal is aluminum, magnesium, and/or titanium and after combining molten aluminum (or magnesium or titanium) and metal halide in the reaction space, substantially removing the produced metal salt to obtain the metal masterbatch which comprises at least a portion of the molten aluminum (or magnesium or titanium) and at least one metal also is described.

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Description

This application claims the benefit under 35 U.S.C. §119(e) of prior U.S. Provisional Patent Application No. 62/374,212, filed Aug. 12, 2016, which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to methods for producing metal powders, salt-coated metal powders, and metal masterbatches.

Metal powders can be used for advanced metallurgical processes, such as near net shape powder pressing, and additive manufacturing, including laser metal deposition (LMD), direct metal laser sintering (DMLS), selective laser sintering (SLS), and selective laser melting (SLM). The end products find applications in a wide variety of industries, including aerospace, medical, and electronics. Other applications include the production of wire bar stock for rolling into medical alloys (e.g., superconducting wires for MRI machines), sputtering targets in electronics manufacturing for thin film metal deposition in displays, use in semiconductors and data storage devices, superalloy production, intermetallic powders for the manufacture of jet engine components, and photovoltaic cells. Metal powders can also be pressed into dense objects using conventional pressing techniques. Salt-coated metal powders can be used for particle strengthening of metals.

Preferably, metal powders are highly pure and have consistent flow properties. However, processes for achieving metal powders having such characteristics require further development. Accordingly, there is a need in the art for methods of making pure metal powders that have adequate flow properties such that the powders can be used for advanced manufacturing applications.

SUMMARY OF THE INVENTION

A feature of the present invention is to provide a process for producing high purity, low oxygen content metal powders with good flow properties.

A further feature of the present invention is to provide a method for producing a metal masterbatch that comprises unreacted aluminum reducing metal and at least one other metal formed from a reaction of the aluminum metal and a metal halide.

A further feature of the present invention is to provide a method for producing a metal masterbatch that comprises unreacted magnesium reducing metal and at least one other metal formed from a reaction of the magnesium metal and a metal halide.

A further feature of the present invention is to provide a method for producing a metal masterbatch that comprises unreacted titanium reducing metal and at least one other metal formed from a reaction of the titanium metal and a metal halide.

Additional features and advantages of the present invention will be set forth in part in the description that follows, and in part will be apparent from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and attained by means of the elements and combinations particularly pointed out in the description and appended claims.

To achieve these and other advantages, and in accordance with the purposes of the present invention, as embodied and broadly described herein, the present invention relates to a method for producing a metal powder. The method includes: a) combining at least one metal halide and at least one molten reducing metal in a space that is substantially free of oxygen and water to obtain a reaction product that includes at least one metal salt and metal; b) substantially removing the molten reducing metal in the reaction product; c) recovering at least the metal, and optionally the at least one metal salt. The molten reducing metal is present in a stoichiometric excess to the metal halide. The molten reducing metal can be primarily 1) sodium and/or potassium or 2) aluminum, or magnesium, or titanium. The at least one metal halide is a solid or liquid, with the proviso that the molten reducing metal is different from the metal of the at least one metal halide. In the reaction product, the metal of the metal salt is the molten reducing metal, and the ‘metal’ recovered from the reaction product is from the metal of the metal halide.

The present invention further relates to a method for producing a metal masterbatch. The method includes: a) combining at least one metal halide and at least one molten reducing metal in a space that is substantially free of oxygen and water to obtain a reaction product that comprises at least one metal salt and metal; b) substantially removing the at least one metal salt to obtain the metal masterbatch comprising at least a portion of the molten reducing metal, and at least one other metal. Step b) can occur as the reaction product forms and/or after the reaction product forms. The molten reducing metal is present in a stoichiometric excess to the metal halide. The molten reducing metal can be or primarily be aluminum or an alloy thereof, magnesium or an alloy thereof, or titanium or an alloy thereof. The at least one metal halide is a solid or liquid, with the proviso that the molten reducing metal is different from the metal of the at least one metal halide. The metal of the metal salt is the molten reducing metal, and the ‘other metal’ recovered from the reaction product is from the metal of the metal halide.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide a further explanation of the present invention, as claimed.

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate some of the features of the present invention and together with the description, serve to explain the principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow chart describing a method according to an example of the present application.

FIG. 2 is a process flow diagram describing a method according to an example of the present application.

FIG. 3 is a process flow diagram describing a method according to an example of the present application.

FIG. 4 is a process flow diagram describing a method according to an example of the present application.

FIG. 5 is a process flow diagram describing a method according to an example of the present application.

FIG. 6 is a schematic illustration of a suitable bake out vessel for a process according to an example of the present application.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to methods of producing metal powders and/or metal masterbatches that incorporate metal halide reduction reactions. These processes can yield high purity and/or low oxygen content products. These methods can be practiced in continuous, semi-continuous, or batch arrangements. As an option, methods can be practiced as a continuous process with recycling of excess reactant. The term “metal powders” can refer to metallic primary particles, aggregates, agglomerates, other discrete metal particles, or any combination thereof. The term “masterbatch” can refer to a physical mixture comprised predominantly of two or more different kinds of metals (e.g. in elemental form), wherein the mixed metals retain their own respective chemical properties and have not chemically reacted with each other. The masterbatch optionally can be or include a metal alloy, an intermetallic compound, metal carbide, metal nitride, metal boride, metal silicide, metal aluminide, or any combination thereof, or other metal compounds (e.g., one or more ceramics) in the alternative or in addition to the indicated physical mixture of different elemental metals.

Metal powders can be formed in a method of the present invention by reducing a solid or liquid metal halide with a molten reducing metal in a sealed reaction vessel that is substantially free of oxygen and water (e.g., below 100 ppm oxygen and below 100 ppm water), wherein the molten reducing metal is present in a stoichiometric excess to the metal halide. Metal powders and a metal salt can be produced, which are separated from the unreacted molten reducing metal. As an option, the metal powder can be separated from the metal salt (e.g., from 95 wt % to 100 wt % of the total metal powder present can be separated from the metal salt).

In the present invention, the molten reducing metal means that the reducing metal is present as a liquid and not a vapor or a solid. For purposes of the present invention, as an option, minor amounts, such as below 5 wt %, below 2.5 wt %, below 1 wt %, below 0.5 wt %, below 0.25 wt %, below 0.1 wt %, below 0.05 wt %, below 0.01 wt % or below 0.001 wt % or zero wt % (based on the total weight of the reducing metal present) can be optionally present in a state other than a liquid or molten state.

In the present invention, the molten reducing metal can comprise, consists essentially of, or consists of, or include either 1) potassium metal or sodium metal or a combination of potassium metal and sodium metal (e.g., an alloy of sodium and potassium), or 2) aluminum metal or alloy thereof, or magnesium metal or alloy thereof, or titanium metal or alloy thereof. For option 1), the molten reducing metal can comprise at least 90 wt % sodium metal, at least 90 wt % potassium metal, or at least 90 wt % of a combination or mixture or alloy of potassium metal and sodium metal. This percent of at least 90 wt % in each instance can be at least 95 wt %, at least 99 wt %, at least 99.5 wt %, at least 99.9 wt %, or 100 wt % such as from 90 wt % to 100 wt %, or from 95 wt % to 100 wt % (all based on the total weight of the molten reducing metal). When the amount of molten reducing metal for potassium and/or sodium is less than 100 wt % but at least 90 wt %, the remaining amount can be, or include for instance other metals in a molten state, such as calcium and/or magnesium and/or one or more other metals, and/or can be one or more oxides. For option 2), the molten reducing metal can comprise at least 90 wt % aluminum metal, or magnesium metal or titanium metal, such as at least 95 wt %, at least 99 wt %, at least 99.5 wt %, at least 99.9 wt %, or 100 wt % such as from 90 wt % to 100 wt %, or from 95 wt % to 100 wt % (all based on the total weight of the molten reducing metal). For purposes of the present invention, the ‘aluminum metal’ can be or include one or more aluminum alloys. These aluminum alloys typically have about 90 wt % or more of aluminum in the alloy based on the total weight of the alloy. For purposes of the present invention, the ‘magnesium metal’ can be or include one or more magnesium alloys. These magnesium alloys typically have about 90 wt % or more of magnesium in the alloy based on the total weight of the alloy. For purposes of the present invention, the ‘titanium metal’ can be or include one or more titanium alloys. These titanium alloys typically have about 90 wt % or more of titanium in the alloy based on the total weight of the alloy. For purposes of the present invention, for either option or any embodiment of the present invention, these percentages for potassium, sodium, aluminum, magnesium, and titanium are based total weight of the components or materials only in the molten state and not in any other state. Also, for purposes of the present invention, unless stated otherwise, reference to “potassium” or “sodium” or “aluminum” or “magnesium” or “titanium” means the above weight percents or purities as provided here. An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by a metallic bonding character. An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). In the case of aluminum alloy, the predominate element is aluminum. In the case of magnesium alloy, the predominate element is magnesium. In the case of titanium alloy, the predominate element is titanium. Preferred percentages are provided above.

In the methods of the present invention, the at least one metal halide can be, include, consists, of or comprises Ti halide, V halide, Cr halide, Mn halide, Fe halide, Co halide, Ni halide, Cu halide, Zn halide, Ga halide, Ge halide, As halide, Se halide, Zr halide, Nb halide, Mo halide, Ru halide, Rh halide, Pd halide, Ag halide, Cd halide, In halide, Sn halide, Sb halide, C halide, Si halide, Te halide, Hf halide, Ta halide, W halide, Hg halide, Tl halide, Pb halide, or Bi halide or any combination thereof. The halide can be chloride, bromide or iodide. Any of the halides in this list can be or exclusively be a chloride (in other words, one or more metal chlorides).

As stated, in the present invention, for the various methods and reactions described herein, the metal of the formed metal salt is (from) the molten reducing metal (e.g., Na, K, or Al, Mg, Ti), and the ‘metal’ recovered from the reaction product is from the metal of the metal halide (e.g, Ti, V, Ta, Nb, Sn, Si, Zr, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, C, Si, Ga, Ge, As, Se, Mo, Ru, Rh, Pd, Ag, Cd, In, Sb, Te, Hf, W, Hg, Ti, Pb, Bi, and the like), or a ceramic thereof, or a nitride thereof, or a boride thereof, or a carbide thereof. Two or more halides can be used. When two or more metal halides are used, one metal halide is reactive and the second metal halide can be reactive or non-reactive with the molten reducing metal. When two or more metal halides are used (e.g, two metal halides, three metal halides or more), each of the metals of the metal halide, if reactive, can result in obtaining a metal alloy of these metals or an intermetallic compound of these metals. If a non-reactive metal halide is present, the metal of the metal halide will not be part of the resulting metal. A non-reactive metal halide, if present, for instance, can be used as an additive, forming a complex halide salt, to lower the melting point of the reactive metal halide, or to reduce the vapor pressure of the reactive metal halide, or to form liquid mixtures or solutions with other metal halides. For instance, NaCl (non-reactive metal halide) can be used with a reactive metal halide (AlCl3). The mol % of the non-reactive metal halide to reactive halide can be from 1:99 to 99:1, and preferably is 20:80 to 80:20, or 40:60 to 60:40, or from 50 mol % to 65 mol % of the non-reactive metal halide to 60 mol % to 35 mol % of the reactive metal halide. A phase diagram of the two metal halides can provide preferred mol % ratios to achieve the desired lower melting point. When two or more halides are used, they can be added as a mixture or separately or at different times. When a non-reactive metal halide is used with a reactive metal halide, the two should be added as a mixture and can be added as a liquid or solid. When two or more metal halides are used, at least one is a solid or liquid, but the other metal halide can be a vapor, liquid, or solid.

As an option, in the present invention, the metal salt formed in any of the processes of the present invention can form a partial or complete coating around the metal that is formed in the reaction product. As described herein, the metal that is formed can be present as a metal powder and be present as primary particles, agglomerates, aggregates, briquettes and the like. The metal salt coating can be any thickness around the metal formed (e.g, around the metal powder), for instance, from about 1 nm to about 100 nm or more, such as from about 100 nm to about 5 μm or from about 500 nm to about 10 μm or thicknesses above or below any of these ranges. The salt coating can be removed by any salt removing technique such as an aqueous washing or sublimation and the like.

The term “substantially free of oxygen and water” as used herein means that any content of oxygen or water present during the combining of the reducing metal and metal halide is insufficient to prevent the metal powder product from having the purity described herein. For instance, the purity (e.g., by wt %) of the finished metal powder can be 95% metal or greater, or 99% metal or greater such as from about 99.5% metal or greater and more preferably 99.95% metal or greater and even more preferably 99.99% metal or greater, or 99.995% metal or greater or 99.999% metal or greater, wherein the metal refers to the metal of the metal halide reactant and not the reducing metal or other source of metal. The metal powders produced by the methods described herein can be highly pure. In particular, the metal powders can have a minimal amount of oxygen bonded to the metal. Reducing the quantity of oxygen bonded to the metal powder has been technically challenging in the art, and thus improvements in metal powder purity represent a substantial technical improvement. The reaction vessel that is substantially free of oxygen and water can be filled or purged with an inert gas, preferably argon, prior to or while maintaining the molten reducing metal in the sealed reaction vessel.

In methods of the present invention, at least one metal halide can be reacted with a stoichiometric excess of a reducing metal. The term “stoichiometric excess” means the molar amount of the molten reducing metal present in the reaction zone is in excess based upon the amount of metal halide present and available to react therewith. The molten reducing metal can be in at least a 5:1 stoichiometric excess to the metal halide, though in some cases it can be less than a 5:1 stoichiometric excess. In other cases, it can be more than a 5:1 stoichiometric excess, such as at least a 10:1 stoichiometric excess, or other values.

When a solid metal halide is used in the method of the present invention, the reducing metal is heated to a temperature above its melting point and below its boiling point to provide a molten material which can be split into a stream that is passed through a cooler to provide a cooled stream that has a temperature that is still above the melting point of the reducing metal and below a reaction temperature of the reducing metal with respect to metal halide, and another stream that is passed through a heater to provide a (further) heated stream of the reducing metal. The split can be from 10:90 to 90:10 by volume (cooled stream:heated stream), or from 20:80 to 80:20, or from 40:60 to 60:40 and the like. The cooled stream of reducing metal is combined with solid metal halide, such as metal halide in powder form, to disperse the metal halide therein to form a mixture (e.g., a slurry). As an option, the heated stream of reducing metal can be heated to a temperature such that when its mass is combined with the mass of the mixture of solid metal halide and cooled reducing metal, the resulting combination has a temperature at or above a reaction temperature of the reducing metal with respect to metal halide. As an option, additional heating can be provided before the combination reaches the reaction zone or, at the reaction zone, or both locations, to provide a reaction temperature. The heated stream of reducing metal and the mixture of cooled reducing metal and solid metal halide can be combined, such as in an eductor, and passed through a reaction zone with the molten reducing metal present in stoichiometric excess to the metal halide to produce a metal reaction product. As indicated, additional heating of the reducing metal and metal halide materials can be provided before and/or in the reaction zone to raise the temperature of the mixture to a reaction temperature, or maintain the materials at a reaction temperature, or both. The space where the metal halide and molten reducing metal are contacting at a reaction temperature, such as the reaction zone, and/or may be in the eductor, preferably are maintained to be substantially free of oxygen and water. The metal reaction product and remaining molten reducing metal can be collected from the reaction zone in a settling and bake out vessel. The remaining (unreacted) molten reducing metal in the reaction product can be substantially removed, such as by pouring or siphoning or other separation method. Metal salt and the metal reaction products that remain in the vessel can be recovered, and the metal reaction product can be separated from the metal salt.

When a liquid metal halide is used in the method, the reducing metal can be passed through a heater to provide a heated liquid stream, such as described hereinabove, that can provide a reaction temperature with respect to metal halide when the heated reducing metal and metal halide are combined, and without the reducing metal being split into different streams for separate cooling and heating. Liquid metal halide is introduced into the heated stream of reducing metal, such as by injection, and the resulting mixture of heated reducing metal and liquid metal halide are passed through a reaction zone with the molten reducing metal present in stoichiometric excess to the metal halide to produce a metal reaction product. The space, such as the reaction zone, or which may be the flow passageway connecting the location of liquid metal halide introduction and the reaction zone, where the metal halide and molten reducing metal are contacting at a reaction temperature, can be maintained to be substantially free of oxygen and water as previously described. The metal reaction product and remaining molten reducing metal can be collected from the reaction zone in a settling and bake out vessel, and the remaining molten reducing metal in the reaction product can be substantially removed, and the metal salt and the metal reaction products that remain can be recovered, and the metal reaction product can be separated from the metal salt, as previously described.

In general, when the molten reducing metal is sodium and/or potassium, once the reaction product is formed and is present with the excess or unreacted molten reducing metal, at least a portion of the excess or unreacted molten reducing metal (e.g., from 10 wt % to 100 wt %, or from 25 wt % to 99.5 wt %, or from 50 wt % to 99 wt %, or from 75 wt % to 99 wt %, or from 85 wt % to 99 wt %, or from 95 wt % to 99.5 wt % by weight of the excess or unreacted molten reducing metal) can be separated from the reaction product (e.g., the metal formed and the metal salt) by causing a phase separation between the excess or unreacted molten reducing metal and the metal and metal salt. Generally in such a process, and if the temperature of the molten reducing metal and metal and metal salt are high enough, the excess or unreacted molten metal will phase separate (liquid phase separation) and generally is on top with the other phase of metal and metal salt at the bottom. This permits easy separation of the two phases by various techniques, such as decanting, siphoning, and the like. This generally occurs when the overall mixture is at a temperature above the melting point of the metal salt present. For instance, when the metal salt is NaCl, a temperature above 801° C. is used to achieve phase separation. Then as stated, the remaining amount of molten reducing metal can be removed by the various techniques described herein.

In general, when the molten reducing metal is aluminum (or alloy thereof), magnesium (or alloy thereof) or titanium (or alloy thereof) phase separation is not used and generally it is preferred to keep the excess or unused aluminum (or magnesium or titanium) present and to instead remove the metal salt of the reaction product by heating the reaction product and excess or unused aluminum (or magnesium or titanium) to a temperature that causes vaporization of the metal salt. This vaporization and removal can occur as the reaction product forms and/or after formation of the reaction product. Any amount of the metal salt can be removed this way, such as from about 10 wt % to 100 wt %, or from 25 wt % to 99.5 wt %, or from 50 wt % to 99 wt %, or from 75 wt % to 99 wt %, or from 85 wt % to 99 wt %, or from 95 wt % to 99.5 wt % by weight of the metal salt present.

The metal powders produced by the methods described herein can have a small particle size, and/or narrow particle size distribution, and/or improved flow characteristics, or any combinations of these, which can be determined using a Hall flow meter according to standardized testing procedures, such as ASTM B213. The methods described herein can produce primary particles having a size ranging from about 5 to about 250 nanometers, or from about 25 to about 200 nanometers, or from about 50 to about 175 micrometers, or from about 75 to about 150 micrometers, or other sizes. The primary particles can form aggregates having an aggregate size of from about 1 to about 250 microns in diameter, from about 25 to about 200 nanometers, or from about 50 to about 175 micrometers, or from about 75 to about 150 micrometers, or other sizes. Particle size can be determined by scanning electron microscopy (SEM) imaging. The particle sizes indicated in this respect can refer to average size, D50 size, or D90 size. Electron microscopy works by bombarding a sample with a stream of electrons and monitoring either the resulting scattering (SEM) effects. These electrons are detected and converted into magnified images of particles in the sample dispersion. Image analysis software uses this information to generate particle size data for individual particles, number based size distributions for the entire dispersion and various shape and morphological parameters. SEM can produce accurate 3D images of particles.

Three variables can exhibit a high degree of influence on powder particle size: the temperature at which the reaction occurs, the relative concentration of the metal halide to the concentration of the reducing metal, and the melting point of the produced metal or alloy powder. Typically, the metal powder particle size is proportional to these variables according to Formula (1), where T is the temperature in Kelvin:

Metal Powder Particle Size α [ [ Concentration of Metal Halide ] [ Concentration of Reducing Metal ] ] T 1 3 ( 1 )

In view of the Formula (1), reaction conditions that favor the production of smaller particles include a lower temperature and a low concentration of metal halide relative to the concentration of the reducing metal. Without wishing to be bound by theory, the process of particle and aggregate formation parallels standard particle flame synthesis processes. Thus, when a primary particle or cluster encounters another cluster, they stick together to form an aggregate that tends to have an open structure, provided the conditions (temperature and particle density) permit continued aggregation. Thus, smaller aggregates are produced when the concentration of the metal halide is lower because the metal powder particles that form are more dispersed in the reducing metal, and therefore the metal powder particles are less likely to physically interact and form aggregates. Finally, the particles are large and cool enough that the aggregates freeze. Additionally, at higher temperatures the particles are stickier so they coalesce for longer. Therefore, the primary particles are larger and have a smaller surface area. At higher concentrations, the particles can collide and coalesce more rapidly before they cool, again leading to larger primary particles and lower surface area.

A method for producing a metal masterbatch is provided that uses a metal halide reduction reaction as part of the process. With aluminum or an alloy thereof used as a reducing metal (in the weight percent amounts indicated earlier) for combining with a solid or liquid metal halide(s) as described herein, the reaction product metal and a salt can be produced in the reaction zone and collected with excess reducing metal in a separate vessel or tank, wherein the salt, and not the excess reducing metal, is separated out, so as to obtain a metal masterbatch comprising at least a portion of the reducing metal and reaction product metal. The reaction product metal can be, depending on the number of different starting metal halides used and types, a metal, a metal alloy, an intermetallic (intermetallic compound), or a ceramic (boride or carbide). For instance, if AlCl3 and carbon tetrachloride are used as the two starting metal halides, the resulting metal can be an aluminum carbide. If the metal halides used are TiCl4 and SiCl4, the resulting metal can be a Ti—Si alloy or intermetallic, and so on. Aluminum trichloride, for instance, sublimates at about 180° C. at one atmosphere pressure, so it can be selectively volatized and removed from excess aluminum and the metal formed from the metal halide reduction reaction which have a higher boiling points. Other aluminum halides with comparable sublimation or vaporization temperatures with respect to aluminum and reaction product metal can be selectively removed in a similar manner.

Another advantage of the methods described herein is that they can reduce the amount of corrosion that occurs. For example, previous gas phase reactions typically offer a lower reaction throughput, and they can also yield substantial corrosion because of the increase in the reaction rate for chloride corrosion processes at elevated temperatures. The methods of the present invention can avoid or have reduced risk of these drawbacks and disadvantages.

As described herein, reacting a metal halide with a molten reducing metal using split flow of heated and cooled streams of molten reducing metal for solid metal halide processing, or injection of liquid metal halide, can yield particles that are highly pure and provide improved flow properties. Preferably, the reactions occur under conditions that remain constant or bounded by a limited range of temperatures and stoichiometry. The methods described herein typically involve steps that are shown in FIG. 1.

The overall process, indicated as 100 in FIG. 1, has several alternatives, including with respect to whether a solid or liquid metal halide is used, whether a metal powder product or a masterbatch product is desired, and other alternatives and options indicated herein. First, molten reducing metal (as described herein), such as 1) sodium, potassium or both, or 2) aluminum or magnesium or titanium, is provided 101. These metals are used for illustration, and other reducing metals may be used. Sodium has a melting point of about 98° C., and aluminum has a melting temperature of about 660° C. Alternative A in the process shown in FIG. 1 is for solid metal halide processing, and alternative B is for liquid metal halide processing. In alternative A, the molten reducing metal is split into two streams (102), wherein a portion of the reducing metal is cooled below a reaction temperature of the metal halide (103A) and the remaining portion is heated to a reaction temperature with metal halide (103B). The cooled stream of reducing metal is fed to an area (e.g., funnel) where solid metal halide is added, such as gravity fed as a dry flowable powder, to the flow of reducing metal through the funnel (104). The metal halide powder combines with the cooled reducing metal, and can form a slurry. The slurry from step 104 and the heated reducing metal are combined in a mixing/dispersing device (105), such as in an eductor. The resulting mixture or dispersion is fed to a reaction zone (106), such as a pipe, mixing tank with an agitator forming a vortex, or other reaction zone arrangement. The metal halide can be reduced by the reducing metal to produce metal particles. In alternative B, the molten reducing metal is heated (122) with no split stream for cooling. Liquid metal halide is injected or otherwise introduced into the heated molten reducing metal (123), and the resulting combination is fed to the reaction zone (106). After the reaction in the reaction zone for either alternative A or B, the remaining, unreacted reducing metal can be removed from the metal particles in a settling/bake out tank (107). The removed excess reducing metal can be recycled by filtering and cooling it for reuse (108). In this option, the salt byproduct then can be removed, and the metal powder particles are recovered (not shown). As shown in FIG. 1, another method of the present invention is the formation of a masterbatch, such as using aluminum reducing metal (or magnesium or titanium), wherein the reaction products and excess (unreacted) reducing aluminum metal (or magnesium metal or titanium metal) from the reaction zone (106) are fed to a volatization/masterbatch formation tank where aluminum salt reaction (or magnesium salt reaction or titanium salt reaction) by-product of the reduction reaction is removed, such as by heat-volatization (124) alone or in combination with other salt removal techniques, to leave unreacted aluminum (or magnesium or titanium) and reaction product metal in the tank as a masterbatch material. For the case of making a masterbatch in “magnesium” or “titanium,” the resulting magnesium or titanium salt is removed as either a slag from the surface of the reducing metal or is heat-volatilized.

Examples of process and equipment arrangements that can be used to perform these process flow options are shown in FIGS. 2, 3, 4, and 5.

In FIG. 2, a method for making a metal powder of the present invention, indicated as 200, is shown which includes use of a solid metal halide 207 and a storage tank 201 of molten reducing metal (e.g., 1) Na and/or K, or 2) Al, Mg, or Ti). The reducing metal is introduced in stoichiometric excess with respect to the metal halide in this method, such as in a range described herein. The sodium and/or potassium reducing metal or aluminum reducing metal (or magnesium reducing metal or titanium reducing metal) is pumped through a continuous loop 214 using pump 202, such as an electromagnetic pump (EM pump). An electromagnetic pump is a pump that moves ionizable liquid metal using electromagnetism. An electromagnetic pump can have no moving mechanical parts which can be corroded by heated reducing metal. A cold trap 203 installed on the loop 214 is used to remove contaminants prior to starting up production. Once the contaminants are removed, the cold trap can be valved off until needed again. The electromagnetic pump 202 pumps the molten sodium and/or potassium or molten aluminum (or molten magnesium or molten titanium) to a flow split 204. As an option, more than a predominant (>50%) amount, or from 51% to 95%, or from 60% to 90%, or from 65% to 85%, or other amounts of the mass flow of the molten reducing metal arriving at split 204 is directed into the stream feeding the heater 208, and a minority amount (<50%), or from 49% to 5%, or from 40% to 10%, or from 35% to 15%, or other amounts is directed to the cooler 205. As an option, the flow to the cooler 205 can be from about 1 to about 7 gallons/min (GPM), or from about 2 to about 6 GPM, or about 3 GPM, or other values, and the flow to the heater 208 can be from about 11 to about 19 GPM, or from about 13 to about 18 GPM, or about 17 GPM, or other values. The split flows can be controlled using valves and Coriolis flow meters (not shown).

The cold sodium and/or potassium stream can be directed to flow around a funnel 206. Metal halide powder, as a solid form of metal halide, can be added to this funnel. The sodium and/or potassium, or the aluminum (or magnesium or titanium) flows around the funnel 206 and can collect the metal halide powder and the resulting mixture or slurry can be drawn through an eductor 209. The eductor 209 can use the hot sodium and/or potassium, or the hot aluminum (or magnesium or titanium) flow as the motive fluid sucking the metal halide slurry into it. The additional heat provided by the hot sodium and/or potassium stream (or the aluminum or magnesium or titanium stream) can initiate the reduction reaction. The reaction can occur in a reaction zone 210. The reaction zone 210 can be a closed pipe, a draft-tube reactor, a stirred tank reactor, or other reactor. As an option, the reaction can occur down a length of spiraling pipe (as the reaction zone 210) to a vessel 211. The reaction zone can be designed to provide turbulence to increase mixing of the reducing metal and metal halide during the reaction, such as by using spiraled piping or a stirred reactor, or other designs. This vessel 210 can collect the product by utilizing the high density of reaction product metal and allowing it to settle to the bottom. The excess sodium and/or potassium or the excess aluminum or magnesium or titanium 215 can flow out of the vessel 211 through an outlet, such as pour spout or decanter or siphon, and then through a filter 212 and a cooler 213 before making it back to the storage tank 201 for reuse.

After the metal production, the settling tank 211 can be used as a bake out vessel. The vessel 211 can be heated to high temperatures until it is void of all excess sodium and/or potassium, or the excess aluminum (or magnesium or titanium), leaving behind a metal/salt mixture. This mixture can be used for post processing.

In the metal halide powder feed system, the feeding of the metal halide powder preferably should occur in an inert atmosphere due to its reactivity in air. As such, the powder transfer to the feed system and all working parts of the feeder itself preferably are maintained in an inert atmosphere, such as an argon atmosphere. If an inert atmosphere is not kept, there can be a risk of heavy chloride corrosion as well as contamination of the product. As an option, a glove box set up around the feeding system can be used. Once the metal halide powder is fed, it preferably is incorporated into the sodium and/or potassium or into the aluminum and/or magnesium and/or titanium in a manner that promotes complete reaction to metal. It has been observed in experiments that metal halide powders, such as HfCl4 powder, is not wetted by liquid sodium, and does not easily disperse, and can form a crust of metal that surrounds and shields unreacted powder from the sodium and/or potassium. The funnel/eductor design is used to disperse the powder into cold sodium and/or potassium or into cold aluminum (or cold magnesium or cold titanium) before sucking it down into the hot sodium and/or potassium, or the hot aluminum (or hot magnesium or hot titanium) and initiating the reaction. This method can provide enough agitation to get the metal halide, such as HfCl4, mixed and promote reaction with sodium and/or potassium, or the aluminum (or magnesium or titanium) once mixed into the hot sodium and/or potassium or the hot aluminum (or hot magnesium or hot titanium). Eductors work based on set flows and pressures on the inlets and the outlet. If the suction is too great for the slurry feed, argon gas can be sucked into the system and can cause problems. As such, a control system can be used to control each flow rate as well as the level in the funnel above the eductor. Further, heat tracing preferably is used throughout the system where reducing metal is stored and passes to monitor the temperatures and for control thereof. If a cold spot in the system should develop, it may cause the sodium or other reducing metal used to freeze and possibly plug up the system.

The settling/bake-out vessel can be a dual purpose piece of equipment that can collect and purify the product. If not transferred or recycled to tank 201 during the reaction and process as indicated, in post production, the vessel can be full of excess molten reducing metal that needs to be removed. This excess molten reducing metal can be removed by raising the temperature to extremely high levels and evaporating the molten reducing metal out. This high temperature may limit the applicable materials of construction and designs. Following this molten reducing metal removal, the vessel itself can be removed from the system for product recovery.

In FIG. 3, a method of making a masterbatch of the present invention, indicated as 300, is shown. In this method, a solid metal halide 307 is used and a tank 301 of aluminum (or magnesium or titanium) is used as a source of reducing metal. Features and steps 302, 314, 303, 304, 305, 306, 307, 308, 309, and 310 can be similar to or the same as features and steps 202, 214, 203, 204, 205, 206, 207, 208, 209, and 210, respectively, as described with respect to method 200 in FIG. 2, and reference is made thereto. The reducing metal is introduced in stoichiometric excess with respect to the metal halide in this method, such as in a range described herein. The method 300 of FIG. 3 differs from the method 200 shown in FIG. 2 with regards to the materials that are removed and retained in the collection tank that receives materials from the reaction zone. In the method 300 of FIG. 3, the volatization/masterbatch tank 311 is used to collect reaction product metal and a salt produced in the reaction zone 310, and also excess aluminum reducing metal (or excess magnesium metal or excess titanium metal). The salt, and not the excess aluminum (or magnesium or titanium) reducing metal, is separated out to obtain a metal masterbatch comprising at least a portion of the aluminum (or magnesium or titanium) reducing metal and reaction product metal. The aluminum (or magnesium or titanium) and reaction product metal can be intermixed as a uniform or substantially uniform physical mixture thereof, which forms or can be formed into a unitary solid mass of material.

In FIG. 4, a method of making a metal powder of the present invention, indicated as 400, is shown. In this method, a liquid metal halide 405 is used instead of a solid metal halide as used in the methods of FIGS. 2 and 3. A tank 401 of sodium and/or potassium, or a tank 401 of aluminum (or magnesium or titanium) is used as a source of reducing metal. The reducing metal is introduced in stoichiometric excess with respect to the metal halide in this method, such as in a range described herein. Features and steps 402, 414, 403, 404, 406, 407, 408, 409, and 415 can be similar to or the same as features and steps 202, 214, 203, 208, 210, 211, 212, 213, and 215, respectively, as described with respect to method 200 in FIG. 2, and reference is made thereto. The liquid metal halide 405 can be introduced into the heated molten reducing metal using an injection or pumping device, such as using pressurized inert gas to force metal flow.

In FIG. 5, a method of making a masterbatch of the present invention, indicated as 500, is shown. In this method, a liquid metal halide 505 is used instead of a solid metal halide as used in the methods of FIGS. 2 and 3, and a masterbatch is formed in a volatization/masterbatch tank 507 used similarly to the tank 311 as used in the method 300 shown in FIG. 3. In method 500, tank 501 of aluminum (or magnesium or titanium) is used as a source of reducing metal. Features and steps 502, 514, 503, 504, 506, 507, and 508 can be similar to or the same as features and steps 302, 314, 303, 308, 310, 311, and 312, respectively, as described with respect to method 300 in FIG. 3, and reference is made thereto. The liquid metal halide 505 can be introduced into the heated molten aluminum (or magnesium or titanium) reducing metal using an injection or pumping device similar to or the same as that described for use in the method 400 of FIG. 4. As in the examples of the methods shown in FIGS. 2-4, the reducing metal is introduced in stoichiometric excess with respect to the metal halide in this method as well, such as in a range described herein.

Additional information on the metal halide reaction and product processing which are related to methods described herein are provided in the following sections.

Metal Halide Reduction

In the metal halide reduction step, when using the indicated liquid or solid forms thereof, the metal halide is reduced to a metal and a metal salt (e.g., from the reducing metal reacting with the halide from the metal halide) is produced as a byproduct.

As indicated, the metal halides can be reacted with a stoichiometric excess of the reducing metal in methods of the present invention. Metal halides that can be reacted include, for example, one or more halides of tantalum, nickel, aluminum, zirconium, vanadium, tin, titanium, silicon, niobium, or hafnium, or any combination thereof. Other examples are mentioned earlier. The metal halide can be a metal chloride. The metal halide can be a metal bromide or metal iodide. The reducing metal is different from the metal of the metal halide, when one metal halide is used. The reducing metal (in molten state) can be or include a Group I metal(s) or aluminum. Examples of reductions include: TaCl5 reduced by sodium; TaCl5 reduced by a mixture of sodium and potassium; HfCl4 reduced by sodium, HfCl4 reduced by a mixture of sodium and potassium; HfCl4 reduced by aluminum; a mixture of TaCl5 and NiCl2 reduced by a mixture of sodium and potassium; AlCl3 reduced by sodium; ZrCl4 reduced by sodium; ZrCl4 reduced by aluminum; VCl4 reduced by sodium; SnCl4 reduced by sodium; TiCl4 reduced by sodium; and SiCl4 reduced by sodium. Subhalides (e.g., halides of lower oxidation states of the metal elements that contain less halide (e.g., TiCl2 or TiCl3) than its common halide (e.g., TiCl4)), including subchlorides, can also be reduced in the same manner, for example, titanium, zirconium, or tin subchlorides. Examples of reduction reactions can proceed according to Equations (2A), (2B), (2C), (2D), (2E), (2F), or (2G):


TaCl5(s or l)+5Na(l)-->Ta(s)+5NaCl(s)  (2A),


HfCl4(s or l)+4Na(l)-->Hf(s)+4NaCl(s)  (2B),


3TiCl4(l)+13Al(l)-->3TiAl3(s)+4AlCl3(g)  (2C),


SiCl4(l)+CCl4(l)+8Al(l)-->SiC(s)+8AlCl3(g)  (2D),


SiCl4(l)+CCl4(l)+4Mg(l)-->SiC(s)+4MgCl2(l)  (2E)


ZrCl4(s or l)+CCl4(l)+2Ti(l)-->ZrC(s)+2TiCl4(g)  (2F)


NaAlCl4(l)+TiCl4(l)+7Na(l)→TiAl(s)+8NaCl(s)  (2G)

In order to generate flowable reducing metal for use in the reaction, the reducing metal is heated to a temperature above its melting point and below its boiling point before it is combined with metal halide and passed into a sealed reaction vessel that is substantially free of oxygen and water. Higher temperatures can lead to the generation of reducing metal vapors that must be controlled. Sodium, for instance, has a melting point temperature of about 98° C. and a boiling point temperature of about 883° C. (at about 1 atmosphere pressure). Aluminum has a melting point temperature of about 660° C. and a boiling point temperature of about 2470° C. (at about 1 atmosphere pressure). It can be advantageous to stay at least 50° C., or at least 100° C., or at least 200° C., or at least 300° C. above the melting point. The heated reducing metal can be initially heated sufficiently to provide a pumpable molten material, and the mixture resulting from its combination with metal halide can have a temperature sufficient to support the metal halide reduction reaction by the initial heating, additional heating before combination with metal halide, or additional heating after combination with metal halide, or any combination thereof. Before combining with the metal halide, the molten reducing metal, depending on the metal, can be heated and maintained at a temperature of from about 150° C. to about 850° C., or from about 150° C. to about 350° C., or from about 200° C. to about 250° C. For example, when the reducing metal is sodium, more typical reaction temperatures are from 150° C. to 350° C., though temperatures up to about 850° C. or other temperatures are possible. In some instances, where the molten reducing metal is sodium, the sodium is heated and maintained at a temperature of from about 600° C. to about 700° C. until combined with the metal halide.

As indicated, the reaction zone can be a closed pipe (e.g., a spiraled pipe), a draft-tube reactor, a stirred tank reactor, or other reactor. The reaction zone preferably creates turbulence which encourages mixing of the reducing agent and metal halide in the reaction zone. As an option, a stirred reactor that can be used, such as described in U.S. patent application Ser. No. 15/051,267, which is incorporated in its entirety by reference herein.

The reaction zone can be a sealed, reaction chamber, which can be an airtight glovebox. An airtight glovebox can be constructed largely of glass plates attached to a metal frame. A glovebox permits an operator to manipulate objects within the glovebox while maintaining an inert reaction environment. The reaction chamber can be a bench-top glovebox, or it can be a larger glovebox suitable for pilot scale operations, in which case it may have work stations where several operators can access the interior of the glovebox. The reaction chamber can also be large enough to house industrial- or commercial-scale reaction vessels. For commercial scale production, an airtight vessel having automated loading and unloading can be used.

For any of the methods of the present invention, including those shown in FIGS. 1-6, optionally, other reactants can also be included during the metal halide reaction which do not interfere with that reaction. For instance, a carbide forming, or nitride forming, or boride forming component (i.e., ceramic forming components) can be added to the metal halide or to the molten reducing metal or both, wherein at least one other metal compound that comprises a metal carbide, a metal nitride, or a metal boride or any combination thereof can be formed. The carbide forming component can comprise carbon containing gas, carbon tetrachloride, or solid carbon. The boride forming component can comprise boron trichloride or one or more boron hydrides. The nitride forming component can be titanium nitride (TiN). The amount of metal carbide, metal nitride, and/or metal boride, or any combination thereof, in the reaction products in lieu of the metal formed, can be from about 10 wt % to about 100 wt % of the total weight reaction product (e.g, from about 40 wt % to 100 wt %, or from 60 wt % from 100 wt % or from 90 wt % to 100 wt %, or from 98 wt % to 100 wt %). From 40 wt % to 100 wt %, or from 60 wt % from 100 wt % or from 90 wt % to 100 wt %, or from 98 wt % to 100 wt % of the metal formed can be converted to the metal carbide, metal nitride, or metal boride in the reaction. The other reactants, such as the carbide or boride or nitride forming component can be added at any stage of the process, such as at or before the reaction zone, or can be present with the reducing metal or with the metal halide introduction point, or be separately introduced using an additional inlet to the flow of the reducing metal or metal halide, or both.

Recycling of Excess Reducing Metal

In another step of the methods such as shown in FIGS. 2 and 4, the excess unreacted molten reducing metal can be separated so that it can preferably be reused in another reduction reaction. The excess reducing metal can be as much as 50% by weight, or more in some cases, of the starting amount of molten reducing metal. As illustrated in FIG. 6, the excess molten sodium and/or potassium, or the excess molten aluminum (or magnesium or titanium) reducing metal 660, along with the metal powder and the sodium salt and/or potassium salt, or the aluminum salt (or magnesium salt or titanium salt) formed during the metal halide reduction reaction step, can be decanted into a bake out vessel 610. The bake out vessel 610 can have a lip 615 that can facilitate the placement of a lid 620 on top of the bake out vessel 610. The bake out vessel 610 can have one or more ports 630 that can be used to remove excess reducing metal material from the bake out vessel 610. The port 630 can be adjustable so that they can extend to differing depths within the bake out vessel 610. The port 630 can be formed of a non-conducting ceramic in order to reduce long-range electron mediated reduction.

To recover the molten reducing metal, the bake out vessel can be heated to just above the melting point of the metal salt formed as a reaction byproduct. For example, when the metal halide is hafnium chloride and the reducing metal is sodium, the salt produced is sodium chloride, which has a melting point of approximately 801° C. In this example, the bake out vessel 610 can be heated to just above 801° C., which is just above the melting point of sodium chloride. At this temperature, the sodium chloride salt begins to melt and separate from the excess (unreacted) sodium reducing metal, thereby creating a salt bath 640 and a molten reducing metal phase 660. A small amount of the sodium dissolves in the molten sodium chloride salt (approximately 2 molar % at 801° C.). The salt bath phase 640 includes sodium salt 641 and the metal powder 645 created by reducing the metal halide. A first outlet or port 630 can use used to pour off (decant) or siphon out the bulk of the excess sodium molten reducing metal 660 by gravity (drain) or by applying a negative relative pressure (siphon) in a capture tank. This molten sodium reducing metal 660 that has been poured off or siphoned off can be captured in a capture tank and reused, such as shown in FIGS. 2 and 4.

The bake out temperature can be adjusted by adding other salts and creating an eutectic system. For example, a 52:48 (by wt) mix of calcium chloride and sodium chloride melts at approximately 500° C. Thus, the bake out can occur in a lower temperature range (e.g., where stainless steel can be used instead of more expensive metals). By operating at a lower temperature, the surface area of the resulting metal powder can also be increased since a higher temperature leads to increased sintering.

Care should be exercised to determine the boundary between the molten reducing metal and the salt so that only the molten reducing metal is removed. It may not be possible to drain or siphon off all of the excess molten reducing metal 660. For example, there may be a layer of reducing metal 660 that is a few millimeters thick that remains after draining or siphoning. As an option, the amount of excess reducing metal (e.g., 1) Na and/or K, or 2) Al and/or Mg and/or Ti) after draining or siphoning can be 5,000 ppm or less in the metal and salt products, such as less than 3,000 ppm, or less than 2,000 ppm, or less than 1,000 ppm, or less than 500 ppm, or less than 250 ppm, or from 0 ppm to 5,000 ppm, or from 10 ppm to 2,000 ppm, or from 100 ppm to 1,500 ppm.

Alternatively, or in addition, residual reducing metal can be reacted with an alcohol, such as methanol.

Once the reducing metal layer has been removed or substantially removed to the ppm levels indicated above, as an option, the remaining reducing metal can be reacted with an anhydrous chloride, such as anhydrous hydrogen chloride (HCl) or chlorine gas (Cl2). However, the hydrochloric acid can attack the metal particles that have been formed. In order to protect the metal particles, a salt can be added to the bake out vessel 610 either prior to or after pouring the molten reducing metal, salt, and metal powder into the bake out vessel 610. Typically, the salt added is the same salt formed during the reduction of the metal halide by the reducing metal. The salt produced in the neutralization reaction typically fills the voids in the metal, and chlorides can therefore attack the metal. By providing a layer of molten salt, direct contact between the halides and the metal can be reduced. Thus, the chloride tends to neutralize the free sodium, which has valence electrons having a long mean free path in the molten salt.

The resulting product can be a metal powder at least partially or fully encapsulated in salt. The salt can have a glass-like appearance because it was melted and cooled.

Salt Removal

In a further step, the salt can be removed. Metal powder having a higher surface area is generally less dense and contains more salt in narrower voids.

In a first method of removing the excess salt from the metal particles, the metal particles encapsulated in salt are washed with water. Preferably, the metal particles encapsulated in salt are transferred to a new vessel prior to the water wash in order to prevent oxidation of the bake out vessel. Frequently, the metal particles are washed in serial batches in a metal beaker or other metal container so that the concentration of salt is less than 1 ppm. An example reaction for removing excess salt is Equation (3), after which the liquids and dissolved solids are removed:


Ta(s)+5NaCl(s)+2H2O(l)->Ta(s)+5NaCl(aq)+2H2O(l)  (3)

In a second method of removing the excess salt from the metal particles, the salt can be evaporated. One method of evaporating the salt is by sweeping an inert gas, such as argon, through the chamber at a temperature close to or above the melting point of the salt, such that the salt has an adequate vapor pressure to permit it to be removed in a reasonable time. The salt vaporizes, leaving behind the metal particles. The procedure can be conducted within a rotary furnace, which can limit the formation of a sponge from the metal particles. The inert gas can be recycled.

In a third method of removing the excess salt from the metal particles, ultrafiltration can be used to remove excess salts. One such system is provided by Koch Membranes.

Metal Powder Recovery

In another further step, the metal particles are recovered and can be subsequently dried if desired. The particles can be dried in a vacuum oven. After drying the metal particles can be collected and recovered as a free flowing powder.

When the metal powder is exposed to air, it can be highly flammable, and its dust can be explosive. Thus, it must be handled with care, and preferably in an inert atmosphere, until the powder has been consolidated into a desired final form or else until the powder surface has been passivated by controlled exposure to oxygen.

Masterbatch Recovery

In masterbatch production, where aluminum is used as the reducing metal and aluminum trichloride (AlCl3), also referred to as aluminum chloride, is the salt formed in the reaction with metal halide, the aluminum trichloride can be selectively separated and removed to leave the reaction product metal and excess aluminum as a masterbatch. The sublimation pressure of the aluminum trichloride reaches one atmosphere at about 179° C. to 183° C. at approximately 1 atmosphere pressure, and the melting-point of aluminum trichloride at 2.5 atmospheres pressure is about 190° C. to 194° C. In view of these properties of aluminum trichloride, the contents of the holding tank can be heated under approximately one atmosphere pressure to at least about 179° C. to 183° C. and below the boiling temperature of aluminum (about 2470° C.) and the reaction product metal (e.g., Hf melt. pt.=about 2233° C., boil. pt.=about 4600° C.) to selectively volatize the aluminum trichloride and separate it from the other contents in the holding tank. Similar processes and reactions can be used when the reducing metal is magnesium or titanium and the a magnesium chloride or titanium chloride, for instance is the salt formed.

The present invention will be further clarified by the following examples, which are intended to be exemplary of the present invention.

EXAMPLES

Example 1 (Theoretical Example)

Using a process flow as illustrated in FIG. 2, a storage tank containing 200 gallons of molten sodium is pumped through a continuous loop using an electromagnetic pump. There is a cold trap installed on the loop that is used to remove contaminants prior to starting up production. Once the contaminants are removed the cold trap is valved off until needed again. The electromagnetic pump pumps the molten sodium to a flow split. The flow to the cooler can be roughly 3 GPM and the flow to the heater can be roughly 17 GPM. The flows can be controlled using valves and Coriolis flow meters.

The cold sodium stream flows around a funnel. The HfCl4 powder is added to this funnel. The sodium flows around the funnel and collects the powder and it is drawn through an eductor. The eductor uses the hot sodium flow as the motive fluid sucking the HfCl4 slurry into it. The additional heat provided by the hot sodium stream initiates the reduction reaction. Feeding of the HfCl4 powder occurs in an inert atmosphere due to its reactivity in air. As such the powder transfer to the feed system and all working parts of the feeder itself is maintained in an inert atmosphere. A small glove box is set up around the feeding system. The reaction occurs down a length of spiraling pipe (reaction zone) to a vessel. This vessel collects the product by utilizing the high density of Hf metal and allowing it to settle to the bottom. The excess sodium flows out of the top of the vessel through a filter and a cooler before making it back to the storage tank.

After the metal production, the settling tank is used as a bake out vessel. The vessel is heated to high temperatures until it is void of all excess sodium, leaving behind a metal/salt mixture. This mixture is taken for post processing by NSP.

Additional examples are provided in the following section.

Example 2: Halide Powder Feed Test

Instrumentation Setup

A powder trickier was used for all halide powder trials to feed the reactant powders to a beaker containing alkali metal(s). This powder feeder consists of an adjustable hopper, discharge tube, stand, and 2-speed control pad. All reactant powders flowed readily through the tube given the vibration frequency at hand, except the TaCl5 and NiCl2 50/50 powder blend. This powder blend packed tightly inside both the tube and the hopper base. As a result, remaining powder was fed to the reaction beaker using a “hand-add” approach with a spatula for the TaCl5 and NiCl2 50/50 blend.

All tests utilized an IKA 70 Watt mixer with the capability of producing speeds from 60 to 2000 rpm. A stainless steel, 1.20 inch diameter, turbine impeller blade was utilized for the first two tests performed, TaCl5 in excess sodium. All subsequent tests were performed using a stainless steel, 1.65 inch diameter, Cowles blade impeller to improve the incorporation of the reactant powder in the alkali metal. Even though the mixer maximum capacity was specified as 2000 rpm maximum, the mixer was utilized at speeds as high as 2135 rpm in the powder feed tests.

A stainless steel 2000 mL beaker was implemented as the reaction vessel for all tests. A lid was constructed for trial 3 with 3 ports for the mixer impeller, powder feed tube, and alkali metal temperature thermocouple (TE-0111A). The lid eliminated a large amount of dusting within the glovebox while allowing for the reactant powder to be fed down into the alkali metal via a vertical feed tube. The 4th and 5th trials used a similar lid with a reduced diameter port to further minimize dusting to the glovebox.

A test setup used for this example is shown and described with reference to FIG. 3 as described in U.S. patent application Ser. No. 15/051,267, which is incorporated in its entirety by reference herein. The stainless steel beaker, V-0100, contained the alkali reducing metal. The reaction beaker was maintained at 200-250° C. using a heater band (controlled via TC-0111) and a hot plate (controlled via TC-0110). The variation in alkali metal temperature was based upon the reactivity of the halide powder during each trial via physical observation. Halide powders were pre-weighed using scale WI-0120 and fed from the powder feeder, F-0125, to V-0100 in 5-10 gram increments.

Argon was fed from an argon supply Dewar to the glovebox at a flow rate of 110 standard cubic feet per hour (scfh). Argon pressure was regulated down to 20-30 psig. The glovebox oxygen and moisture content was recorded prior to the start of each trial. Before any halide powders were exposed to the glovebox internals, the blower was de-energized and the purifier was isolated in an effort to preserve the integrity of the purifier. With the purifier isolated from the system, oxygen content was not accurately displayed on the glovebox control panel because the oxygen sensor was also sensitive to chlorides, and therefore provided an inaccurate reading due to the presence of chloride vapors in the glovebox.

A vacuum filtration system was incorporated for the trials using NaK. This system consists of a filtration separation vessel, V-0134, that contains a 10 micron screen inserted within a stainless steel cup to retain the solids. A catch vessel (flask), V-0135, was used to prevent any filtered NaK carry-over and to protect the vacuum pump, PU-0130. This vacuum filtration set-up was also used to perform the methanol wash steps within product recovery when NaK was utilized.

Test Procedure and Results

A first experiment was conducted to assess the minimum reaction temperature and mixing parameters. In this first experiment, an inert atmosphere having as little oxygen and moisture as possible was established in the glovebox. The hot plate and heater bands were energized and set to 200° C. Once the alkali metal was up to temperature, a pinch test was performed by adding a small amount of reactant powder to the alkali metal. The pinch test must be performed with the lid removed from the vessel to observe for signs of reaction (such as a change in color or the generation of smoke). If no sign of reaction was observed at 200° C., then the temperature was increased in increments of 50° C. and the pinch test was repeated until a reaction was observed. All reactions were performed at 250° C. or less.

The halide powders were manually weighed in 5-10 gram increments before being added to the hopper. Powder was fed from the hopper to the vessel, with pauses in feeding when smoking was observed. When the reaction step was completed, the mixer, heater band, and hot plate were de-energized to allow for the system to cool before the start of product recovery.

A total of five experiments was performed; two utilized TaCl5 and molten sodium, whereas the remaining three reacted TaCl5, HfCl4, and a 50/50 (wt %) mix of TaCl5 and NiCl2, each with NaK alloy. A consolidation of the test results displaying the amount of fed halide powder, the amount of alkali metal used, and the final amount of collected product after vacuum drying can be viewed for each test in Table 1 below.

TABLE 1 Reactant Charges and Fractional Yield Summary Charged Recovered Fractional Yield Fed Halide Alkali Product (actual/theoretical Test Powder (g) Metal (g) (g) product) 1. TaCl5 in 0.50 90.00 0.05 19.8% Excess Na 2. TaCl5 in 19.15 957.00 0.50 5.2% Excess Na 3. TaCl5 in 41.16 748.00 13.60 65.4% Excess NaK 4. HfCl4 in 23.78 718.70 9.80 74.0% Excess NaK 5. TaCl5/NiCl2 19.26 728.40 5.20 56.4% in Excess NaK

At the start of Test 5, NiCl2 showed no sign of reaction at 200° C. when performing a pinch test; however, a reaction was visible at 250° C. Therefore, Test 5 was performed at 250° C.

The 50/50 wt % NiCl2/TaCl5 (Test 5) powder mix tightly packed within the hopper feed tube, as well as the base of the hopper, multiple times. As a result, approximately half of the feed was added to the NaK-containing vessel manually using a spatula.

For the first two trials utilizing sodium, filtration took place in the reaction beaker, with the second test using a removable screen (<500 mesh) placed within the vessel. Material was scraped from the reaction vessel (and screen for the second test) before adding methanol to react residual sodium held up within the product. The reaction products were centrifuged for 0.5-2.0 hours at 3000 rpm and decanted, and a second methanol wash was repeated, followed by a de-ionized water wash to passivate the tantalum product. A second de-ionized water wash was performed using nitric acid to achieve a solution with a pH of 2. After decanting, the sample was then vacuum dried overnight at 95° C.

For the trials performed with NaK, the vacuum filtration system in the glovebox was utilized to remove the excess NaK from the reacted product. Two methanol washes were performed to react any NaK held up with the product, and vacuum filtration was used to remove excess solvent within the product cake. As with the first two tests, methanol washing was followed by a de-ionized water wash in the glovebox to passivate the product followed by centrifugation at 3000 rpm for 30 minutes and decanting. A total of five or six water washes were performed before the product was vacuum dried overnight at 85-95° C. Each test performed with NaK utilized varying deionized (DI) water solutions based on the product isoelectric points. Table 2 describes the pH of the solutions used for water washing as well as the number of washes performed. Solution pH was adjusted using nitric acid or sodium hydroxide.

TABLE 2 Water Wash Criteria for Products Generated Using NaK DI Water Wash No. of Performed Test Solution pH Washes 3. TaCl5 in Excess 2-3 6 NaK 4. HfCl4 in Excess 7 6 NaK 5. TaCl5/NiCl2 in Half at 2.50-3.0; Half at 10-11 5 Excess NaK

Other observations include the following:

Significant dusting was observed in the glovebox for Tests 1 and 2, which were performed with an open lid. The rotation of the mixer shaft can create argon currents that disperse some of the powder feed. Dusting was observed again for Test 3, but dusting significantly decreased so that very little was observed for Tests 4 and 5, which utilized a lid.

When draining excess sodium from the product in Test 2, it was difficult to determine if the sodium drained through the inner mesh strainer assembly or if a hole was present in the mesh. Furthermore, some dark material (most likely tantalum) was removed with the excess sodium, and caught in the <500 mesh strainer.

Sufficient mixing was established with the mixer running at 1625-1675 rpms in Test 3; however, once powder addition began, the mixing speed was increased to 1750 rpms to maintain a good vortex and surface movement.

The hafnium tetrachloride powder used in Test 4 was denser and chunkier than the tantalum pentachloride previously used. Larger HfCl4 chunks appeared to sink in the NaK with no visible signs of reaction, whereas the loose, fine powder generated smoke and changed in color from white to black upon contact with NaK. The HfCl4 powder was filtered to remove these larger chunks prior to feeding the hopper and starting the reaction.

At the start of Test 5, NiCl2 showed no sign of reaction at 200° C. when performing a pinch test; however, a reaction was visible at 250° C. Therefore, Test 5 was performed at 250° C.

The 50/50 wt % NiCl2/TaCl5 powder mix tightly packed within the hopper feed tube, as well as the base of the hopper, multiple times. As a result, approximately half of the feed was added to the NaK-containing vessel manually using a spatula.

The amount of fed halide powder used in the last, fifth trial is a best estimate due to losing approximately 0.86 g when the feed tube on the lid assembly plugged during the feeding process.

Salt Concentration Test

A salt concentration test was performed to assess the quantity of metal halides that can be added while maintaining a vortex. A total of 797.17 grams of sodium were used, and a total of 477.69 g NaCl were added over the course of the trial. The first five salt charges were added in increments of 10 g, and all subsequent charges were fed in 25 g increments.

After feeding 154.88 g of NaCl, a white-grey film skimmed over the surface of the sodium and surface motion was halted. When increasing the mixer speed from 1611 to 1750 RPMs, surface motion resumed in pockets. At a mixing speed of 1950 rpms, swirling became visible, but a vortex was still not observed. At 2008 rpms, an off-centered vortex developed to the left of the mixer shaft.

Once NaCl addition reached 399.74 g, surface movement again ceased, but regenerated after four minutes of no movement. After adding 424.74 g of NaCl, movement again ceased, but was re-initiated by probing the surface with a flat blade. The salt feed was stopped at 477.69 g, afterchanges in fluid density and viscosity were observed and surface mixing no longer occurred.

All tests demonstrated that the halide powder-alkali metal reactions can be performed at 200° C. except for NiCl2, which should be reacted with alkali metals at 250° C.

A dispersion of sodium and sodium chloride can have approximately 33 to 37 wt % salt before changes in fluid density and viscosity were observed and surface mixing no longer occurred.

Example 3: Halide Powder and Liquid Initiation Test

Instrumentation Setup

A second set of experiments was conducted to verify the reactivity of various powder and liquid halides with sodium metal. All tests were performed in a glovebox, inerted with argon to eliminate oxygen and moisture from the atmosphere.

Powder halide transfer: Aluminum Trichloride and Zirconium (IV) Chloride powders were transferred into weighing dishes using a microspatula. The powders were then poured into the reaction cups from the weighing dishes.

Liquid halide transfer: Vanadium (IV) Chloride, Tin (IV) Chloride, Titanium (IV) Chloride, and Silicon Tetrachloride were transferred into the reaction cups using 1 mL syringes. For each liquid halide, a volume of 0.1 mL was transferred into a syringe. The syringes were then placed in the glovebox. The syringes were then used to inject drops of each liquid halide into a reaction cup containing molten sodium metal.

Reaction vessel: Stainless steel 2.5 oz. cups were implemented as the reaction vessels for all tests. When not in use, stainless steel foil was placed on top of each reaction cup.

A test setup used for this example is shown and described with reference to FIG. 4 as described in U.S. patent application Ser. No. 15/051,267, which is incorporated in its entirety by reference herein. Each stainless steel cup, V-0100 through V-0600 contained sodium metal. The reaction cups were maintained at 240−260° C. using a hot plate (manually controlled via TC-0110). Halide powders were pre-weighed using scale WI-0120 and poured into V-0100 and V-0200. The scale used to weigh the powder halides only displays increments of 0.1 grams; therefore, the amount of halide powders added to each reaction cup was known to be less than 0.1 grams. Halide liquids were injected into the reactions cups using 1 mL syringes. Because of the limited dexterity in the glovebox and hazards associated with handling syringe needles, the liquid halides were transferred from storage bottles into syringes under the fume hood. The syringes were then placed in the glovebox. For each halide liquid, 0.1 mL or less was injected into the reaction cups V-0300 through V-0600. The setup for the liquid halides was the same with the exception that four reaction cups were used instead of two.

Argon was fed from an argon supply Dewar to the glovebox at a flow rate of 65-70 scfh. Argon pressure was regulated down to 20-30 psig.

The glovebox oxygen and moisture content was recorded prior to the start of each trial. Before any halide powders were exposed to the glovebox internals, the blower was de-energized and the purifier was isolated in an effort to preserve the integrity of the purifier. With the purifier isolated from the system, oxygen content was not accurately displayed on the glovebox control panel.

Test Procedure and Results

Each test began with equipment set-up in the glovebox, and establishing an inert atmosphere. The hot plate was energized and set to 250° C. In order to reach and maintain a sodium temperature of 250° C., the hot plate was set between 350° C. and 400° C. Once the sodium metal was up to temperature, the halides were added to the reactions cups one at a time. The tests were performed with the lid (foil) removed from the cup to observe signs of reaction (such as a change in color or the generation of smoke). If no sign of reaction was observed at 250° C., then the temperature was increased in increments of 50° C. and the test was repeated until a reaction was observed. All reactions were performed at 250° C. in order to establish a safe minimum temperature.

Two experiments with halide powders were performed utilizing powdered AlCl3 and ZrCl4 reacted with molten sodium. Table 3 lists the consolidated test results displaying the amount of halide powder added, the amount of sodium metal used, the reaction temperature, and any observations during the reaction.

TABLE 3 Halide Powder Reaction Results Charged Halide Sodium Powder Metal Reaction Test Added (g) (g) Temp (C.) Observations 6. AlCl3 in <0.1 9.7 245 Color change to dark gray Excess Na 7. ZrCl4 in <0.1 9.9 250 Color change to dark gray Excess Na

Other observations from the test include the following: ZrCl4 did not react as immediately as AlCl3.

Four experiments were performed utilizing liquid VCl4, SnCl4, TiCl4, and SiCl4 reacted with molten sodium. Table 4 lists the consolidated test results displaying the amount of halide liquid added, the amount of sodium metal used, the reaction temperature, and any observations during the reaction.

TABLE 4 Halide Reaction Results Halide Charged Liquid Sodium Added Metal Reaction Test (mL) (g) Temp (C.) Observations 8. VCl4 in 0.1 10.0 245 Color change to black Excess Na Temperature increase of 3° C. 9. SnCl4 in 0.03 9.9 256 Color change to dark gray Excess Na Blue flame Some SnCl4 evaporation 10. TiCl4 in 0.02 10.0 251 Color change to black Excess Na Some TiCl4 evaporation 11. SiCl4 in 0.08 10.1 251 SiCl4 mostly evaporated on Excess Na sodium surface Color change to dark gray

Other observations from the tests include the following:

After transfer into the syringes, fuming out of the end of the needle was noticed with VCl4, SnCl4, and TiCl4. In the case of SnCl4 and TiCl4, fuming stopped once the needles were inserted into rubber stoppers. In the case of VCl4, fuming continued for 2 minutes after the needle was inserted into the rubber stopper.

There was some pressure build up with the VCl4 syringe. Some VCl4 was released from the syringe when the stopper was removed from the end of the needle while in the glovebox.

TiCl4 changed from clear to yellow while in the syringe.

There appeared to be more oxide on the sodium surface for the SiCl4 reaction which could have resulted in the majority of the SiCl4 laying on the surface and slowly evaporating instead of reacting. SiCl4 is also more volatile than the other liquid halides tested.

AlCl3, ZrCl4, VCl4, SnCl4, TiCl4, and SiCl4 all react with sodium at approximately 250° C. There is potentially some evaporation when the liquid halides are introduced to sodium at 250° C.

Example 4: Metal Powder Characterization

Particle flow can be measured according to a standardized protocol, such as by using a Hall flow meter according ASTM International Standard B213.

Molecular content of the metal powders produced by the methods described herein can be determined using LECO testers. For example, nitrogen and oxygen content can be tested with LECO Model TC436DR. Carbon and sulfur content can be tested with LECO Model CS444LS. Nitrogen, oxygen, and hydrogen content can be tested with LECO Model TCH600.

Purity can be assess by glow discharge mass spectrometry or inductively coupled plasma mass spectrometry.

Example 5: Titanium Powder

140 g of sodium metal was melted and brought to 250° C. in an Inconel reactor vessel. The sodium was then stirred using a Cowles blade mixer rotating at 2200-2300 rpm. Liquid titanium chloride (from Sigma Aldrich) was fed over approximately 1 hour into the stirred sodium, until 60 g of titanium chloride had been added, at which point the reaction was halted by releasing the gas pressure on the halide feed. At the end of the reaction, the vortex in the sodium had substantially disappeared.

Once the reaction was completed, the reactor vessel was sealed, transferred to a furnace, and heated to 825° C. for four hours to reduce the surface area of the titanium metal produced in the reaction.

After the high temperature treatment, the unreacted sodium was removed from the reaction products and the titanium powder, coated in salt, was washed in water to remove the coating of sodium chloride encapsulating the metal. Washing continued until washwater conductivity fell below 2 microsiemens.

The recovered titanium powder was dried overnight in a vacuum oven at 100° C. The titanium powder thus produced was analysed by inductively coupled plasma mass spectrometry (ICP-MS) and LECO instruments, and was found to contain below 150 ppm iron, below 300 ppm total transition metals, and below 3000 ppm oxygen. The results demonstrate that the titanium powder falls within the purity limits as described in UNS No. R50550.

Visual assessment of SEM images showed particle agglomerates predominantly in the 50 micron range, with primary structure mainly at 3-5 microns.

Example 6: Hafnium Metal

113 g of sodium metal was melted and brought to 250° C. in an Inconel reactor vessel. The sodium was then stirred using a Cowles blade mixer rotating at 2000-2500 rpm. Powdered hafnium chloride (from Areva) was pulse-fed over approximately 1 hour into the stirred sodium, until 82 g of hafnium chloride had been added, at which point the reaction was halted. At the end of the reaction, the vortex in the sodium had substantially disappeared and the reactor temperature had increased to 301° C.

Once the reaction was completed, the reactor vessel was sealed, transferred to a furnace, and heated to 825° C. for four hours to reduce the surface area of the hafnium metal produced in the reaction. During this process step, unreacted sodium was removed from the hafnium metal to leave a hafnium-sodium chloride composite.

The hafnium and sodium chloride mixture was then transferred to a vacuum furnace and heated under vacuum to 2300° C., held at that temperature for one hour, and then cooled. This removed the sodium chloride and produced a button of solid hafnium.

The hafnium button was analysed via glow discharge mass spectrometry (GDMS) and found to have 26 ppm oxygen content, 1690 ppm zirconium, and less than 150 ppm total transition metals. The results demonstrate the production of a low oxygen hafnium metal produced directly from hafnium powder consolidation.

Example 7: Titanium-Aluminum

120 g of a 55% aluminum, 45% titanium powder (measured by metal content) was first prepared, by adding aluminum chloride powder (from Strem Chemical) to an aluminum-titanium chloride Ziegler Natta catalyst powder (also from Strem Chemical).

Next, 140 g of sodium metal was placed in an Inconel reactor and heated to 250° C. Over approximately 2 hours, 94 g of the titanium-aluminum chloride powder mix was pulse fed into the sodium, which was continuously stirred by a Cowles blade mixer at between 1600 and 2500 rpm. Powder addition continued until the mixer could no longer maintain a vortex in the sodium. At the end of the reaction the sodium temperature had increased to 292° C.

The Inconel reactor was then sealed, transferred to a furnace, and heated to 900° C. for 1 hour. After this step, the unreacted sodium was removed and the metal powder washed to remove its salt coating. Washing continued until the wash water conductivity fell below 2 microsiemens. Finally, the powder was dried in a vacuum over for 24 hours. The titanium-aluminum metal thus produced was found by ICPMS analysis to contain below 100 ppm iron and below 150 ppm total transition metals.

Example 8: Titanium-Aluminum-Vanadium

First, 120 g of a titanium-aluminum-vanadium chloride mixture was prepared, by mixing liquid titanium chloride (from Sigma Aldrich), aluminum chloride powder (from Strem Chemical) and liquid vanadium chloride (from Acros Organics). The mixture was stirred constantly to dissolve the aluminum trichloride into the titanium chloride and vanadium chloride liquid.

Next, 140 g of sodium metal was heated to 250° C. in an Inconel vessel and stirred by a Cowles blade mixer at speeds ranging from 1000 rpm initially, to 2500 rpm as the reaction progressed. The liquid chloride mixture was pumped into the reactor until 74 g had been added, over approximately 90 minutes. The reaction stopped when the vortex in the sodium could no longer be maintained.

The reactor vessel was then sealed and transferred to a furnace, brought to 825° C. and held at that temperature for approximately one hour before being allowed to cool.

The recovered product was then washed to remove the sodium chloride coating the metal powder, and the powder was dried in a vacuum oven at 100 C for 24 hours. The results demonstrate that the titanium powder falls within the purity limits as described in UNS No. R56400.

Example 9: γ-Titanium-Aluminide (Ti 48Al2Nb 2Cr)

First, 200 g of a titanium-aluminum-niobium-chromium chloride mixture was prepared, by mixing liquid titanium chloride (from Sigma Aldrich), sodium aluminum chloride powder (NaAlCl4) (from Sigma-Aldrich), niobium chloride (from Sigma Aldrich), and sodium chromium chloride powder (Na3CrCl5) (produced from NaCl and CrCl2 both from Sigma Aldrich). The mixture was heated to 180° C. under 10 bar of pressure with constant stirring to maintain a well mixed liquid chloride feed.

Next, 5 kg of sodium metal was heated to 250° C. in an Inconel vessel and stirred by a Cowles blade mixer at speeds ranging from 1000 rpm initially, to 2500 rpm as the reaction progressed. The chloride mixture was pumped into the reactor until 200 g had been added, over approximately 90 minutes. The reaction stopped when the vortex in the sodium could no longer be maintained.

The reactor vessel was then sealed and transferred to a furnace, brought to 825° C. and held at that temperature for approximately one hour before being allowed to cool.

The recovered product was then washed to remove the sodium chloride coating the metal powder, and the powder was dried in a vacuum oven at 100 C for 24 hours.

Analysis of the metal powder using ICPMS showed the product contained under 50 ppm iron and under 150 ppm total transition metals different from those used to make the alloy. From EDX analysis, the γ-titanium-aluminide composition fell within the specification of Al: 32.4-33.6 wt % Cr: 2.4-2.8 wt % Nb: 4.5-5.1 wt %.

The present invention includes the following aspects/embodiments/features in any order and/or in any combination:

  • 1. A method for producing a metal powder, the method comprising:
    • a) combining at least one metal halide and at least one molten reducing metal in a space that is substantially free of oxygen and water, wherein said molten reducing metal is present in a stoichiometric excess to the metal halide, to obtain a reaction product that comprises at least one metal salt and metal, and wherein the molten reducing metal comprises i) at least 90 wt % sodium or potassium or a mixture of potassium and sodium or ii) at least 90 wt % aluminum, magnesium, or titanium based on total weight of said molten reducing metal, and the at least one metal halide is a solid or liquid, with the proviso that the molten reducing metal is different from the metal of the at least one metal halide;
    • b) substantially removing unreacted said molten reducing metal in said reaction product;
    • c) recovering at least said metal, wherein the metal of the metal salt is the molten reducing metal, and the ‘metal’ recovered from the reaction product is from the metal of the metal halide.
  • 2. The method of any preceding or following embodiment/feature/aspect, wherein in step c), the at least one metal salt is recovered with said metal.
  • 3. The method of any preceding or following embodiment/feature/aspect, wherein said method further comprises d) separating said metal from said metal salt.
  • 4. The method of any preceding or following embodiment/feature/aspect, wherein two or more metal halides are used and wherein said metal recovered comprises a metal alloy or intermetallic compound from each metal of the two or more metal halides.
  • 5. The method of any preceding or following embodiment/feature/aspect, wherein said at least one metal halide is at least one metal chloride.
  • 6. A method for producing a metal masterbatch, the method comprising:
    • a) combining at least one metal halide and at least one molten reducing metal in a space that is substantially free of oxygen and water, wherein said molten reducing metal is present in a stoichiometric excess to the metal halide, to obtain a reaction product that comprises at least one metal salt and metal, and wherein the molten reducing metal comprises at least 90 wt % aluminum, magnesium, or titanium based on total weight of said molten reducing metal, and the at least one metal halide is a solid or liquid, with the proviso that the molten reducing metal is different from the metal of the at least one metal halide;
    • b) substantially removing said at least one metal salt to obtain said metal masterbatch comprising at least a portion of said molten reducing metal, and the metal, wherein the metal of the metal salt is the molten reducing metal and the ‘metal’ recovered from the reaction product is from the metal of the metal halide, wherein the removing of at least one metal salt occurs during or after formation of said reaction product.
  • 7. The method of any preceding or following embodiment/feature/aspect, wherein said at least one metal halide comprises Ti halide, V halide, Cr halide, Mn halide, Fe halide, Co halide, Ni halide, Cu halide, Zn halide, Ga halide, Ge halide, As halide, Se halide, Zr halide, Nb halide, Mo halide, Ru halide, Rh halide, Pd halide, Ag halide, Cd halide, In halide, Sn halide, Sb halide, C halide, Si halide, Te halide, Hf halide, Ta halide, W halide, Hg halide, Tl halide, Pb halide, or Bi halide or any combination thereof
  • 8. The method of any preceding or following embodiment/feature/aspect, wherein said at least one metal halide is at least one metal chloride.
  • 9. The method of any preceding or following embodiment/feature/aspect, wherein two or more metal halides are used and wherein said metal recovered comprises a metal alloy, intermetallic compound, or ceramic from each metal of the two or more metal halides.
  • 10. The method of any preceding or following embodiment/feature/aspect, wherein said at least one metal halide is at least one metal chloride.
  • 11. The method of any preceding or following embodiment/feature/aspect, wherein said metal masterbatch comprises aluminum, hafnium, and zirconium.
  • 12. The method of any preceding or following embodiment/feature/aspect, further comprising adding a carbide, nitride, or boride forming component to said metal halide or to said molten reducing metal or both, and wherein said metal of the reaction product comprises a metal carbide, a metal nitride, or a metal boride or any combination thereof.
  • 13. The method of any preceding or following embodiment/feature/aspect, wherein said carbide forming component comprises carbon containing gas, carbon tetrachloride or solid carbon.
  • 14. The method of any preceding or following embodiment/feature/aspect, wherein said boride forming component comprises boron trichloride or a boron hydride.
  • 15. The method of any preceding or following embodiment/feature/aspect, wherein said substantially removing said at least one metal salt comprises vaporization of said at least one metal salt and removal thereof from said metal masterbatch.
  • 16. The method of any preceding or following embodiment/feature/aspect, wherein said at least one metal halide is combined as a solid with said molten reducing metal.
  • 17. The method of any preceding or following embodiment/feature/aspect, wherein said at least one metal halide is combined as a solid with a portion of said molten reducing metal to form a mixture, and said portion of said molten reducing metal is at a temperature that avoids reaction with said metal halide.
  • 18. The method of any preceding or following embodiment/feature/aspect, said method further comprising combining said mixture with part or all of the remaining portion of said molten reducing metal that is at a temperature that permits reaction with said metal halide.
  • 19. The method of any preceding or following embodiment/feature/aspect, wherein said combined at least one metal halide and at least one molten reducing metal passes through a reaction zone that comprises at least one closed pipe that causes turbulence in combined at least one metal halide and at least one molten reducing metal and that optionally empties into a tank or filter.
  • 20. The method of any preceding or following embodiment/feature/aspect, wherein said molten reducing metal comprises said at least 90 wt % sodium or potassium or a mixture of potassium and sodium, and wherein combined at least one metal halide and at least one molten reducing metal passes through a reaction zone that empties into a settling tank that includes at least one outlet that is located at a height in the settling tank that permits said molten reducing metal from step b) to at least partly be removed by said outlet but not said molten salt or said metal, and wherein said combined at least one metal halide, at least one molten reducing metal, and at least one metal salt together are at a temperature that results in phase separation of the molten reducing metal from said metal salt and said metal.
  • 21. The method of any preceding or following embodiment/feature/aspect, wherein said combining said mixture with part or all of the remaining portion of said molten reducing metal that is at a temperature that permits reaction with said metal halide comprises utilizing an eductor.
  • 22. The method of any preceding or following embodiment/feature/aspect, prior to at least step b), wherein said molten reducing metal comprises at least 90 wt % sodium or potassium or a mixture of potassium and sodium, and wherein at least one metal halide, at least one molten reducing metal and at least one metal salt together are at a temperature that causes phase separation of the molten reducing metal from said metal salt and said metal.
  • 23. The method of any preceding or following embodiment/feature/aspect, wherein said substantially removing said at least one metal salt comprises permitting the vaporization of at least a portion of said at least one metal salt and removal thereof from said metal masterbatch.
  • 24. The method of any preceding or following embodiment/feature/aspect, wherein the at least one metal halide comprises at least a first metal halide and a second metal halide, with the first metal halide reactive with the metal salt and the second metal halide non-reactive with the metal salt, wherein the metal of the second metal halide is the same or different from the molten reducing metal.
  • 25. The method of any preceding or following embodiment/feature/aspect, wherein the second metal halide is NaCl and the molten reducing metal is said at least 90 wt % sodium, and the first metal halide is AlCl3.
  • 26. The method of any preceding or following embodiment/feature/aspect, wherein said at least one metal halide comprises a halide of Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Hg, Tl, Pb, or Bi or any combination thereof.
  • 27. The method of any preceding or following embodiment/feature/aspect, wherein said first metal halide and said second metal halide form a eutectic mixture.
  • 28. The method of any preceding or following embodiment/feature/aspect, wherein said at least one metal halide is two or more metal halides, and one metal halide is a solid or liquid and the other metal halide is a vapor, solid, or liquid.
  • 29. The method of any preceding or following embodiment/feature/aspect, wherein said at one least metal halide is three or more metal halides, and one metal halide is a solid or liquid and the other metal halides are a vapor, solid, or liquid.
  • 30. The method of any preceding or following embodiment/feature/aspect, wherein said metal salt at least partially coats or encapsulates said metal.
  • 31. The method of any preceding or following embodiment/feature/aspect, wherein said molten reducing metal is aluminum alloy.
  • 32. The method of any preceding or following embodiment/feature/aspect, wherein said molten reducing metal is magnesium alloy.
  • 33. The method of any preceding or following embodiment/feature/aspect, wherein said molten reducing metal is titanium alloy.

The present invention can include any combination of these various features or embodiments above and/or below as set forth in sentences and/or paragraphs. Any combination of disclosed features herein is considered part of the present invention and no limitation is intended with respect to combinable features.

Applicant specifically incorporates the entire contents of all cited references in this disclosure. Further, when an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.

Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the present specification and practice of the present invention disclosed herein. It is intended that the present specification and examples be considered as exemplary only with a true scope and spirit of the invention being indicated by the following claims and equivalents thereof

Claims

1. A method for producing a metal powder, the method comprising:

a) combining at least one metal halide and at least one molten reducing metal in a space that is substantially free of oxygen and water, wherein said molten reducing metal is present in a stoichiometric excess to the metal halide, to obtain a reaction product that comprises at least one metal salt and metal, and wherein the molten reducing metal comprises i) at least 90 wt % sodium or potassium or a mixture of potassium and sodium or ii) at least 90 wt % aluminum, magnesium, or titanium based on total weight of said molten reducing metal, and the at least one metal halide is a solid or liquid, with the proviso that the molten reducing metal is different from the metal of the at least one metal halide;
b) substantially removing unreacted said molten reducing metal in said reaction product;
c) recovering at least said metal, wherein the metal of the metal salt is the molten reducing metal, and the ‘metal’ recovered from the reaction product is from the metal of the metal halide.

2. The method of claim 1, wherein in step c), the at least one metal salt is recovered with said metal.

3. The method of claim 2, wherein said method further comprises d) separating said metal from said metal salt.

4. The method of claim 1, wherein two or more metal halides are used and wherein said metal recovered comprises a metal alloy or intermetallic compound from each metal of the two or more metal halides.

5. The method of claim 1, wherein said at least one metal halide is at least one metal chloride.

6. A method for producing a metal masterbatch, the method comprising:

a) combining at least one metal halide and at least one molten reducing metal in a space that is substantially free of oxygen and water, wherein said molten reducing metal is present in a stoichiometric excess to the metal halide, to obtain a reaction product that comprises at least one metal salt and metal, and wherein the molten reducing metal comprises at least 90 wt % aluminum, magnesium, or titanium based on total weight of said molten reducing metal, and the at least one metal halide is a solid or liquid, with the proviso that the molten reducing metal is different from the metal of the at least one metal halide;
b) substantially removing said at least one metal salt to obtain said metal masterbatch comprising at least a portion of said molten reducing metal and the metal, wherein the metal of the metal salt is the molten reducing metal, and the ‘metal’ recovered from the reaction product is from the metal of the metal halide, wherein the removing of at least one metal salt occurs during or after formation of said reaction product.

7. The method of claim 1, wherein said at least one metal halide comprises Ti halide, V halide, Cr halide, Mn halide, Fe halide, Co halide, Ni halide, Cu halide, Zn halide, Ga halide, Ge halide, As halide, Se halide, Zr halide, Nb halide, Mo halide, Ru halide, Rh halide, Pd halide, Ag halide, Cd halide, In halide, Sn halide, Sb halide, C halide, Si halide, Te halide, Hf halide, Ta halide, W halide, Hg halide, Tl halide, Pb halide, or Bi halide or any combination thereof.

8. The method of claim 6, wherein said at least one metal halide is at least one metal chloride.

9. The method of claim 6, wherein two or more metal halides are used and wherein said metal recovered comprises a metal alloy, intermetallic compound, or ceramic from each metal of the two or more metal halides.

10. The method of claim 1, wherein said at least one metal halide is at least one metal chloride.

11. The method of claim 6, wherein said metal masterbatch comprises aluminum, hafnium, and zirconium.

12. The method of claim 6, further comprising adding a carbide, nitride, or boride forming component to said metal halide or to said molten reducing metal or both, and wherein said metal of the reaction product comprises a metal carbide, a metal nitride, or a metal boride or any combination thereof.

13. The method of claim 12, wherein said carbide forming component comprises carbon containing gas, carbon tetrachloride or solid carbon.

14. The method of claim 12, wherein said boride forming component comprises boron trichloride or a boron hydride.

15. The method of claim 6, wherein said substantially removing said at least one metal salt comprises vaporization of said at least one metal salt and removal thereof from said metal masterbatch.

16. The method of claim 1, wherein said at least one metal halide is combined as a solid with said molten reducing metal.

17. The method of claim 16, wherein said at least one metal halide is combined as a solid with a portion of said molten reducing metal to form a mixture, and said portion of said molten reducing metal is at a temperature that avoids reaction with said metal halide.

18. The method of claim 17, said method further comprising combining said mixture with part or all of the remaining portion of said molten reducing metal that is at a temperature that permits reaction with said metal halide.

19. The method of claim 1, wherein said combined at least one metal halide and at least one molten reducing metal passes through a reaction zone that comprises at least one closed pipe that causes turbulence in combined at least one metal halide and at least one molten reducing metal and that optionally empties into a tank or filter.

20. The method of claim 1, wherein said molten reducing metal comprises said at least 90 wt % sodium or potassium or a mixture of potassium and sodium, and wherein combined at least one metal halide and at least one molten reducing metal passes through a reaction zone that empties into a settling tank that includes at least one outlet that is located at a height in the settling tank that permits said molten reducing metal from step b) to at least partly be removed by said outlet but not said molten salt or said metal, and wherein said combined at least one metal halide, at least one molten reducing metal, and at least one metal salt together are at a temperature that results in phase separation of the molten reducing metal from said metal salt and said metal.

21. The method of claim 18, wherein said combining said mixture with part or all of the remaining portion of said molten reducing metal that is at a temperature that permits reaction with said metal halide comprises utilizing an eductor.

22. The method of claim 1, prior to at least step b), wherein said molten reducing metal comprises at least 90 wt % sodium or potassium or a mixture of potassium and sodium, and wherein at least one metal halide, at least one molten reducing metal and at least one metal salt together are at a temperature that causes phase separation of the molten reducing metal from said metal salt and said metal.

23. The method of claim 1, wherein said substantially removing said at least one metal salt comprises permitting the vaporization of at least a portion of said at least one metal salt and removal thereof from said metal masterbatch.

24. The method of claim 1, wherein the at least one metal halide comprises at least a first metal halide and a second metal halide, with the first metal halide reactive with the metal salt and the second metal halide non-reactive with the metal salt, wherein the metal of the second metal halide is the same or different from the molten reducing metal.

25. The method of claim 6, wherein the at least one metal halide comprises at least a first metal halide and a second metal halide, with the first metal halide reactive with the metal salt and the second metal halide non-reactive with the metal salt, wherein the metal of the second metal halide is the same or different from the molten reducing metal.

26. The method of claim 24, wherein the second metal halide is NaCl and the molten reducing metal is said at least 90 wt % sodium, and the first metal halide is AlCl3.

27. The method of claim 25, wherein the second metal halide is NaCl and the molten reducing metal is said at least 90 wt % sodium, and the first metal halide is AlCl3.

28. The method of claim 6, wherein said at least one metal halide comprises Ti halide, V halide, Cr halide, Mn halide, Fe halide, Co halide, Ni halide, Cu halide, Zn halide, Ga halide, Ge halide, As halide, Se halide, Zr halide, Nb halide, Mo halide, Ru halide, Rh halide, Pd halide, Ag halide, Cd halide, In halide, C halide, Si halide, Sn halide, Sb halide, Te halide, Hf halide, Ta halide, W halide, Hg halide, Tl halide, Pb halide, or Bi halide or any combination thereof.

29. The method of claim 24, wherein said first metal halide and said second metal halide form a eutectic mixture.

30. The method of claim 1, wherein said at least one metal halide is two or more metal halides, and one metal halide is a solid or liquid and the other metal halide is a vapor, solid, or liquid.

31. The method of claim 6, wherein said at one least metal halide is two or more metal halides, and one metal halide is a solid or liquid and the other metal halide is a vapor, solid, or liquid.

32. The method of claim 1, wherein said metal salt at least partially coats or encapsulates said metal.

33. The method of claim 1, wherein said molten reducing metal is aluminum alloy.

34. The method of claim 1, wherein said molten reducing metal is magnesium alloy.

35. The method of claim 1, wherein said molten reducing metal is titanium alloy.

36. The method of claim 6, wherein said molten reducing metal is aluminum alloy.

37. The method of claim 6, wherein said molten reducing metal is magnesium alloy.

38. The method of claim 6, wherein said molten reducing metal is titanium alloy.

Patent History

Publication number: 20180043437
Type: Application
Filed: Aug 7, 2017
Publication Date: Feb 15, 2018
Applicant: Nanoscale Powders, LLC (Boston, MA)
Inventors: Donald Finnerty (New Freedom, PA), David Henderson (Concord, NH), John Koenitzer (Carlisle, MA), Andrew Matheson (Belmont, MA), Richard Van Lieshout (New Freedom, PA)
Application Number: 15/669,984

Classifications

International Classification: B22F 9/24 (20060101); C22B 34/12 (20060101); C22C 14/00 (20060101); C22B 34/14 (20060101);