Method for Producing Titanium-containing Electrodeposit and Metal Titanium Electrodeposit

Provided is a method for producing a titanium-containing electrodeposit, which can achieve good refinement by an electrodeposition without using the Kroll method. A method for producing a titanium-containing electrodeposit, including an electrodeposition step of electrodepositing a titanium-containing electrodeposit in a chloride bath, the chloride bath being a molten salt, using an anode including a TiAlO conductive material containing titanium, aluminum, and oxygen, and a cathode, wherein, in the electrodeposition step, a current density of the cathode is in a range of 0.3 A/cm2 or more and 2.0 A/cm2 or less, and wherein the chloride bath contains 1 mol % or more of a titanium subchloride.

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Description
TECHNICAL FIELD

The present invention relates to a method for producing a titanium-containing electrodeposit and a metal titanium electrodeposit.

BACKGROUND ART

In general, production of metal titanium is carried out by a Kroll process. However, the production requires many steps.

By the way, techniques of mainly producing a titanium alloy by an electrodeposition are conventionally known in the art. For example, Patent Literature 1 discloses a method for producing a titanium alloy by heating a raw material containing titanium ore and aluminum and then subjecting the obtained material to electrodeposition.

Also, Patent Literature 2 discloses a method for electrolytically refining a titanium-aluminide containing more than 10% by mass of aluminum and at least 10% by mass of oxygen.

CITATION LIST Patent Literature [PTL 1]

    • Japanese Patent Application Publication No. 2015-507696 A

[PTL 2]

    • Japanese Patent Application Publication No. 2020-507011 A

SUMMARY OF INVENTION Technical Problem

A low oxygen content may be required for titanium alloy products and titanium metal products. Here, it would be advantageous if a raw material can be refined into a titanium-containing electrodeposit having a low oxygen content and the like by an electrodeposition.

Thus, in an embodiment, an object of the present invention is to provide a method for producing a titanium-containing electrodeposit and a metal titanium electrodeposit, which can achieve good refinement by an electrodeposition without using the Kroll method.

Solution to Problem

As a result of extensive studies, the present inventors have found that it is advantageous for good refinement to set a concentration of a titanium subchloride in a chloride bath and a current density of a cathode to predetermined ranges during the electrodeposition. In this case, it is believed that the resulting titanium-containing electrodeposit is coarsened and an oxygen content of the titanium-containing electrodeposit is appropriately reduced. Further, in this case, a current efficiency per an electrodeposition may be improved. As described above, based on the findings of the present inventors, it is possible to produce a metal titanium electrodeposit having a low impurity content.

Thus, in an aspect, the present invention relates to a method for producing a titanium-containing electrodeposit, comprising an electrodeposition step of electrodepositing a titanium-containing electrodeposit in a chloride bath, the chloride bath being a molten salt, using an anode comprising a TiAlO conductive material containing titanium, aluminum, and oxygen, and a cathode, wherein, in the electrodeposition step, a current density of the cathode is in a range of 0.3 A/cm2 or more and 2.0 A/cm2 or less, and wherein the chloride bath contains 1 mol % or more of a titanium subchloride.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, a temperature of the chloride bath is 730° C. or more.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, the chloride bath contains 6 mol % or more of the titanium subchloride.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, the method comprises a generation step of generating the titanium subchloride by bringing metal titanium and titanium tetrachloride into contact with each other in a chloride bath, before the electrodeposition step.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, the method comprises a generation step of generating the titanium subchloride by bringing sponge titanium and titanium tetrachloride into contact with each other in a chloride bath, before the electrodeposition step.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, further comprising an extracting step of heating a chemical blend comprising a titanium ore containing titanium oxide, aluminum, and a separating agent to obtain the TiAlO conductive material, before the electrodeposition step.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, the separating agent comprises one or more selected from calcium fluoride, calcium oxide and sodium fluoride.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, a refined titanium-containing electrodeposit is obtained by performing multiple electrodepositions in the electrodeposition step.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, the refined titanium-containing electrodeposit has an aluminum content of 1000 ppm by mass or less, an oxygen content of 500 ppm by mass or less, and a chlorine content of 500 ppm by mass or less.

In an embodiment of the method for producing a titanium-containing electrodeposit according to the present invention, the refined titanium-containing electrodeposit has a nitrogen content of 0.03% by mass or less, a carbon content of 0.01% by mass or less, an iron content of 0.010% by mass or less, a magnesium content of 0.05% by mass or less, a nickel content of 0.01% by mass or less, a chromium content of 0.005% by mass or less, a silicon content of 0.001% by mass or less, a manganese content of 0.05% by mass or less, and a tin content of 0.01% by mass or less.

In another aspect, the present invention relates to a metal titanium electrodeposit, wherein the metal titanium electrodeposit has an aluminum content of 5 ppm by mass or more and 1000 ppm by mass or less, an oxygen content of 100 ppm by mass or more and 500 ppm by mass or less, and a chlorine content of 500 ppm by mass or less.

In an embodiment of the metal titanium electrodeposit according to the present invention, the metal titanium electrodeposit has a nitrogen content of 0.001% by mass or more and 0.03% by mass or less, a carbon content of 0.0004% by mass or more and 0.01% by mass or less, an iron content of 0.010% by mass or less, a magnesium content of 0.05% by mass or less, a nickel content of 0.01% by mass or less, a chromium content of 0.005% by mass or less, a silicon content of 0.001% by mass or less, a manganese content of 0.05% by mass or less, and a tin content of 0.01% by mass or less.

Advantageous Effects of Invention

According to an embodiment of the present invention, it is possible to provide a method for producing a titanium-containing electrodeposit and a metal titanium electrodeposit, which can achieve good refinement by an electrodeposition without using the Kroll method.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1(A) to (D) are diagrams for explaining an electrodeposition step in an embodiment of a method for producing a titanium-containing electrodeposit according to the present invention.

FIGS. 2(A) to (D) are diagrams for explaining an electrodeposition step in another embodiment of a method for producing a titanium-containing electrodeposit according to the present invention.

FIGS. 3(A) to (D) are diagrams for explaining an electrodeposition step in another embodiment of a method for producing a titanium-containing electrodeposit according to the present invention.

FIGS. 4(A) to (D) are diagrams for explaining an electrodeposition step in another embodiment of a method for producing a titanium-containing electrodeposit according to the present invention.

FIGS. 5(A) to (D) are diagrams for explaining an electrodeposition step in another embodiment of a method for producing a titanium-containing electrodeposit according to the present invention.

FIGS. 6(A) to (D) are diagrams for explaining an electrodeposition step in Example 1.

FIG. 7 is an end view taken along the line X-X of FIG. 6(A).

FIG. 8(A) is a photograph of a refined titanium-containing electrodeposit obtained in Example 7 after two electrodepositions, and FIG. 8(B) is a photograph obtained by SEM observation of a refined titanium-containing electrodeposit obtained in Example 7 after two electrodepositions.

 DESCRIPTION OF EMBODIMENTS

The present invention is not limited to embodiments described below, and it can be embodied by modifying components without departing from the spirit of the present invention. Moreover, various inventions can be formed by appropriately combining a plurality of components disclosed in each embodiment. For example, the invention may be formed by omitting some components from all the components shown in the embodiments. In addition, in the drawings, some members are schematically shown in order to facilitate understanding of the embodiments included in the invention, and illustrated sizes, positional relationships, and the like, may not necessarily be accurate.

Also, as used herein, the “titanium subchloride” means a subchloride of titanium (more particularly, TiCl2 and/or TiCl3) having a lower chlorine number than titanium tetrachloride, and the “titanium ions” means titanium ions in which an ionic valence x of Tix+ is 2 and/or 3.

[1. Method for Producing Titanium-Containing Electrodeposit]

In an embodiment, a method for producing a titanium-containing electrodeposit according to the present invention includes an electrodeposition step for reducing an impurity content. It should be noted that an extraction step and/or a generation step may be further included before the electrodeposition step. When the extraction step and the generation step are included, these steps may be carried out in any order, one of these steps may be first carried out, or these steps may be carried out at substantially the same time.

An example of each step is described below.

<Extraction Step>

In the extraction step, for example, a chemical blend containing titanium ore containing titanium oxide, aluminum, and a separating agent are heated to obtain a TiAlO conductive material. That is, in the extraction step, a thermite reaction would be used to reduce titanium oxide, which is a metal oxide, with aluminum. The chemical blend is a raw material mixture for obtaining a TiAlO conductive material. Titanium oxide in the titanium ore is not suitable for the electrodeposition due to its low electrical conductivity. Therefore, the TiAlO conductive material can be produced by performing the extraction step using the titanium ore. Since the TiAlO conductive material has a relatively high electrical conductivity, it can be used in an electrodeposition step for producing metal titanium, which will be described below. In the extraction step, the TiAlO conductive material may be produced by appropriately referring to the known method described in Patent Literature 1 (Japanese Patent Application Publication No. 2015-507696) or the like.

(Titanium Ore)

Although the content of titanium oxide in the titanium ore is not limited, it is, for example, 50% by mass or more, for example, 80% by mass or more, and for example, 90% by mass or more. The titanium ore includes ore that has been obtained by mining, as well as ore that has been so-called upgraded. When the content of titanium oxide in the titanium ore is lower, an appropriate treatment such as leaching may be carried out to improve (i.e., upgrade) the content of titanium oxide.

(Separating Agent)

The separating agent is mixed into the chemical blend for the purpose of separating the TiAlO conductive material from a slag as a by-product, in the extraction step. An agent having such a function can be used as a separating agent, and it preferably contains one or more selected from calcium fluoride, aluminum fluoride, potassium fluoride, magnesium fluoride, calcium oxide and sodium fluoride. From the viewpoint of morphology, the separating agent more preferably contains calcium fluoride. Therefore, the separating agent may be calcium fluoride alone.

(Chemical Blend Composition)

In order to produce the above chemical blend, for example, amounts of titanium ore, aluminum and separating agent introduced are adjusted so that a molar ratio of titanium oxide:aluminum:separating agent=3:4-7:2-6, for example. Thus, the molar ratio of titanium oxide, aluminum and separating agent in the chemical blend is 4/3 or more and 7/3 or less of aluminum, and 2/3 or more and 2 or less of the separating agent, per one of titanium oxide.

(Heating Conditions)

For the heating conditions, a temperature inside a container is, for example, 1500° C. or more and 1800° C. or more in an inert gas (e.g., Ar) atmosphere. Examples of a material for an inner wall of the container include carbon, ceramics, and the like, in terms of heat resistance and the like.

(TiAlO Conductive Material)

The TiAlO conductive material obtained in the extraction step has, for example, a titanium content of 50% by mass or more and 80% by mass or less, an aluminum content of 3% by mass or more and 40% by mass or less, and an oxygen content of 0.2% by mass or more and 40% by mass or less. According to the present invention, even a TiAlO conductive material having a high aluminum content and high oxygen content can be satisfactorily refined by carrying out an electrodeposition step as described below.

The lower limit of the titanium content is, for example, 60% by mass or more.

Also, the lower limit of the aluminum content is, for example, 5% by mass or more. Further, the upper limit of the aluminum content is, for example, 30% by mass or less, for example, 20% by mass or less.

Also, the lower limit of the oxygen content is, for example, 3% by mass or more, 5% by mass or more, or 8% by mass or more. Further, the upper limit of the oxygen content is, for example, 30% by mass or less, for example, 20% by mass or less.

In addition, as for the method for measuring the impurity content of each component of the TiAlO conductive material, the measuring method described in Examples of this specification can be used.

(Specific Resistance)

The upper limit of the specific resistance of the TiAlO conductive material may be, for example, 1×10−4 Ω·m or less, in terms of producing the titanium-containing electrodeposit. Also, the lower limit of the specific resistance may be, for example, 1×10−8 Ω·m or more, for example, 1×10−7 Ω·m or more, for example, 5×10−7 Ω·m or more, because the TiAlO conductive material may be moderately energized.

With regard to the method for measuring the resistivity of the TiAlO conductive material, the measuring method described in Examples of this specification can be used.

Generation Step

The generation step includes bringing titanium metal and titanium tetrachloride into contact with each other in a chloride bath to generate a titanium subchloride. The metal titanium may be sponge titanium, or metal titanium produced by carrying out the production method according to the present invention, or titanium scrap thereof. Among metal titanium to be allowed to react with titanium tetrachloride, a material such as sponge titanium, which has a certain size and can be placed in a chloride bath, can be used as it is. When fine metal titanium such as powder is brought into contact with titanium tetrachloride, the fine metal titanium such as powder may be used as it is, or the fine metal titanium such as powder may be processed to a certain size such as by compression molding, and then placed in the chloride bath. Hereinafter, from the viewpoint of convenience of explanation, an embodiment where sponge titanium is used as the metal titanium, and the sponge titanium and the titanium tetrachloride are brought into contact with each other will be described. In addition, even if other metal titanium is used, the same method can be carried out to generate the titanium subchloride.

In an embodiment, the generation step includes bringing sponge titanium and titanium tetrachloride into contact with each other in a chloride bath to produce a titanium subchloride. For example, the sponge titanium can be brought into sufficient contact with titanium tetrachloride with stirring or the like while heating and maintaining the chloride bath at a predetermined temperature, thereby further improving a generation efficiency of the titanium subchloride. The titanium subchloride can be used as a source of titanium ions in the chloride bath in the electrodeposition step.

From the viewpoint of generating the titanium subchloride by bringing the sponge titanium and titanium tetrachloride into sufficient contact with each other, an amount (mol) of sponge titanium may be slightly larger than an amount (mol) of titanium tetrachloride, and the sponge titanium and titanium tetrachloride may preferably be added in a molar ratio of 6:4 to 7:3, for example. Titanium tetrachloride is often brought into contact with the sponge titanium as a liquid or a gas, whereas the sponge titanium is a solid. Therefore, it is possible to reduce the amount of unreacted titanium tetrachloride and efficiently generate the titanium subchloride in the above molar ratio range.

The temperature of the chloride bath is maintained, for example, in the range of 700 to 900° C. from the viewpoint of ensuring a sufficient reaction rate. The time for which the temperature is maintained may be 2 hours or more, for example, 3 to 10 hours, from the viewpoint of production efficiency. However, the time for which the temperature is maintained may be longer depending on the production equipment, and may be, for example, 10 hours or longer.

In the generation step, for the sake of explanation, the TiAlO conductive material obtained in the extraction step is not placed in the chloride bath, but after placing the TiAlO conductive material obtained in the extraction step in the chloride bath, the titanium subchloride may be generated.

<Electrodeposition Step>

In the electrodeposition step, the impurity content of the TiAlO conductive material is reduced to refine the TiAlO conductive material into a titanium-containing electrodeposit. At this time, the titanium-containing electrodeposit is electrodeposited in a chloride bath, which is a molten salt, using an anode containing a TiAlO conductive material and a cathode, for example, in an electrolytic device described below. In this embodiment, it is preferable to use a chloride bath containing 1 mol % or more of a titanium subchloride at the start of electrodeposition, and to set a current density of the cathode to a range of 0.3 A/cm2 or more and 2.0 A/cm2 or less. Thus, it is believed that the chloride bath will contain titanium ions (Ti2+ and Ti3+) ionized from the titanium subchloride even at the initial stage of the electrodeposition step, and during the electrodeposition, the titanium ions near the cathode are reduced and the titanium-containing deposit is electrodeposited onto the cathode. On the other hand, in the anode, the titanium ions are eluted from the TiAlO conductive material into the chloride bath. In the electrodeposition step, the TiAlO conductive material can be refined into a titanium-containing electrodeposit having reduced contents of mainly oxygen and other ore-derived elements. Further, as described above, it is believed that the chloride bath contains the titanium subchloride, and the current density is in the predetermined range, whereby the titanium-containing deposit would be coarsened, and the oxygen content derived from the oxide film would be reduced. Furthermore, the current efficiency per one electrodeposition becomes relatively high. As a result, a well-refined titanium-containing electrodeposit can be obtained from the titanium ore used in the extraction step after the electrodeposition step without using the Kroll method.

(Electrolytic Device)

In an embodiment, various electrolytic devices can be used. An example of an electrolysis device 100 shown in FIG. 1(A) is of a batch type, and includes a device including: an electrolytic bath 110 in a form of a sealed container that stores a chloride bath Bf; an electrode including anodes 120 and a cathode 130 that are immersed and arranged in the chloride bath Bf; and a power source (not shown) connected to the anodes 120 and the cathode 130 via electrically conductive lines EL to conduct current through the anodes 120 and the cathode 130. Although not shown, the electrolytic device 100 typically has a structure that can be opened and closed in order to install or take out the anode and the cathode. Although not shown, the electrolytic device 100 may have an opening for feeding or discharging a gas in order to make the space above the chloride bath Bf an inert gas atmosphere. Although not shown, the electrolytic device 100 may be provided with a heater at an appropriate position, so that the chloride bath Bf can be maintained in a molten state by heating. The material of the electrolytic bath 110 is not particularly limited as long as it has heat resistance and corrosion resistance. Also, the electrodes may further include a bipolar electrode.

(Molten Salt)

The molten salt that forms the chloride bath may contain, for example, 80 mol % or more, for example, 85 mol % or more, for example, 90 mol % or more, of an alkali metal chloride and an alkaline earth metal chloride. The chloride bath contains at least one metal chloride selected from lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl2), rubidium chloride (RbCl), cesium chloride (CsCl), beryllium chloride (BeCl2), calcium chloride (CaCl2)), strontium chloride (SrCl2), and barium chloride (BaCl2). Among these metal chlorides, it is preferable to contain one or more selected from sodium chloride, potassium chloride, and magnesium chloride. In particular, when the chloride bath contains magnesium chloride, the chloride bath may contain, for example, 30 mol % or more, for example 50 mol % or more, for example 80 mol % or more, for example 90 mol % or more, of magnesium chloride. Magnesium chloride is excellent in reducing the aluminum content in the electrodeposition step. In the present invention, reasons why a fluoride bath, a bromide bath and an iodide bath are not used in place of the chloride bath include high corrosiveness, high environmental load and high cost.

In an embodiment, the chloride bath contains 1 mol % or more of the titanium subchloride. Although the chloride bath contains 1 mol % or more of the titanium subchloride at the start of electrodeposition, it is preferable that the chloride bath contains 1 mol % or more of the titanium subchloride during the electrodeposition. Also, the titanium subchloride can be generated in the chloride bath in the generation step as described above, but the titanium subchloride separately prepared before the electrodeposition in the electrodeposition step may be mixed into the chloride bath without carrying out the generation step. The concentration of the titanium subchloride in the chloride bath is preferably 3 mol % or more, and more preferably 5 mol % or more, and even more preferably 6 mol % or more, and most preferably 10 mol % or more. If it exceeds the saturation concentration of the titanium subchloride in the chloride bath, the production efficiency does not significantly vary, so that the upper limit is the saturation concentration, for example, 20 mol % or less. When the titanium subchloride is generated in the chloride bath by the above generation step, the amounts of sponge titanium and titanium tetrachloride introduced may be appropriately adjusted in view of the desired concentration of the titanium subchloride. The concentration of the titanium subchloride tends to increase as the amounts of these introduced amounts increase.

The chloride bath may consist of an alkali metal chloride, an alkaline earth metal chloride, a titanium subchloride and unavoidable impurities. In such a case, the contents in the ranges as described above can be appropriately adopted.

For types and contents of chlorides other than the titanium subchloride, the specific type and content of salts can be determined as appropriate in view of an operating temperature and the like. The content on a molar basis is measured by ICP emission spectrometry and atomic absorption spectrometry.

Here, the above content on the molar basis is calculated as follows. After solidifying a molten salt sample collected from the chloride bath, the components of the sample are subjected to ICP emission spectrometry and atomic absorption spectrometry to calculate the content of each metal ion on a molar basis in the chloride bath Bf. If the chloride bath contains MgCl2, NaCl, KCl, CaCl2), LiCl, TiCl2 and TiCl3, the total metal ion content (Mn) is determined by adding up the content of magnesium ions, the content of sodium ions, the content of potassium ions, the content of calcium ions, the content of lithium ions, and the content of titanium ions, measured by the atomic absorption spectrometry for Na, K and Li, and by ICP emission spectrometry for the other elements. As shown in the following equation (1), the concentration on the molar basis for titanium ions contained in the chloride bath can be calculated by dividing the metal ion content of each component by the total metal ion content (Mn), and expressing it as a percentage. As used herein, the concentration of titanium ions (Ti2+ and Ti3+) in the chloride bath is regarded as the concentration of the titanium subchloride in chloride bath.


Concentration of titanium ions[mol %]=(titanium ion content in chloride bath[mol/L]/total metal ion content in chloride bath[mol/L])×100  Equation (1)

(Anode and Cathode)

Each of the anode 120 and the cathode 130 can have a suitable shape, including, for example, a rod shape, a long band that is used while being moved, a cylindrical shape, a plate shape, a columnar shape or other pillar shapes, or a block shape. For example, the TiAlO conductive material as the anode 120 can be melted and cast to form the anode. If the distance between the electrodes of the anode 120 and the cathode 130 is to be set within a specific range, it is preferable that the shapes of the anode 120 and the cathode 130 in a vertical cross section to the opposing portions are analogous. For example, if a cylindrical, rod shaped, or pillar shaped cathode 130 is used and the anode 120 is placed outside it, the anode 120 may also be cylindrical. In this case, the cylindrical anode 120 surrounds the cathode 130, so that the area where the electrodeposits are produced can be increased. Alternatively, a rod shaped or pillar shaped cathode 130 that is rotatable with a fixed axial position may be used, and a plate shaped anode 120 having an arc shaped cross section may be used at the opposed portion. Even in this case, the opposing portions of the anode 120 and the cathode 130 can maintain substantially the same distance between the electrodes.

Alternatively, the anode 120 may be formed by placing the TiAlO conductive material obtained in the above extraction step in the form of granules or powder in a metal basket (for example, a nickel basket, nickel alloy basket, Hastelloy basket, etc.) having a lower ionization tendency than that of titanium. In this case, the basket BK has many through holes, and the shape of the basket BK can be regarded as the shape of the anode 120. Further, even if current conduction is intended for the basket BK, the basket BK is difficult to be eluted into the chloride bath Bf, and the TiAlO conductive material is mainly eluted. In the description using the drawings, for ease of understanding, the portion where the TiAlO conductive material or the like is eluted is sometimes described with the reference numeral of the anode. From the viewpoint of corrosion resistance, examples of materials for the basket include nickel, Ni-based alloys (e.g., Hastelloy), iron and carbon. From the viewpoint of impact resistance, the material is preferably nickel, a Ni-based alloy (e.g., Hastelloy), and iron, and more preferably nickel.

Also, as for the shape of the cathode 130, at least a part of the surface of the cathode 130 on which the metal titanium is deposited may be curved. The use of such a cathode 130 allows the metal titanium to be electrodeposited on the surface of the cathode 130 while rotating the cathode 130, which contributes to miniaturization of the device during continuous production.

The electrodeposition may be performed once or multiple times in the electrodeposition step. When the electrodeposition is performed once, a titanium base alloy or a titanium alloy for addition to steel can be produced as a titanium-containing electrodeposit obtained by the electrodeposition, and when the electrodeposition is performed multiple times, metal titanium can be produced as a refined titanium-containing electrodeposit obtained in the final electrodeposition.

Next, examples of the electrodeposition step (where the electrodeposition is performed twice) will be described with reference to FIGS. 1(A) to (D) through FIGS. 5(A) to (D).

When the chloride bath used in the first electrodeposition contains the predetermined amount of the titanium subchloride as described above, the chloride bath used in the second and subsequent electrodepositions may contain the above predetermined amount of the titanium subchloride. Also, the predetermined amount of the titanium subchloride may not be contained. It should be noted that the material electrodeposited in a bath that does not contain the predetermined amount of the titanium subchloride can be used as the TiAlO conductive material for the first electrodeposition.

Also, each of electrically conductive lines shown in FIGS. 1(A) to (D) through FIGS. 5(A) to 5(D) can be connected to a power supply (not shown), and a control mechanism (not shown) for the power supply is capable of appropriately switching the electrically conductive lines for supplying current according to each anode and each cathode.

In the first electrodeposition step, a titanium-containing electrodeposit is obtained by performing the electrodeposition using an electrode containing a TiAlO conductive material in a chloride bath Bf.

For example, in the first electrodeposition, as shown in FIG. 1(A), nickel baskets BK each having the TiAlO conductive material as the anode 120 and a titanium cathode 130 are arranged in the chloride bath Bf. The control mechanism then supplies current to the anodes 120 and the cathode 130 via electrically conductive lines EL connected to the baskets BK and the cathode 130, thereby performing the electrodeposition.

Although the anodes 120 are placed in separate baskets BK in the drawings, the anodes may be placed in, for example, ring shaped nickel baskets (see FIGS. 6(A) and 7). Alternatively, a rod shaped or plate shaped anode obtained by casting the TiAlO conductive material may be directly connected to the electrically conductive line without using the basket.

(Current Density)

The current density of the cathode 130 is in the range of 0.3 A/cm2 or more and 2.0 A/cm2 or more. The lower limit of the current density of the cathode is, for example, 0.4 A/cm2 or more, or 0.5 A/cm2 or more, and the upper limit is, for example, 1.8 A/cm2 or less, or 1.6 A/cm2 or less. The current density of the cathode 130 can be calculated by the equation: current density (A/cm2)=current (A)/electrolytic area (cm2). Here, for example, in the case of a cathode having a cylindrical surface, the electrolytic area is calculated by the equation: electrolytic area (cm2)=cathode immersion surface area=cathode diameter (cm)×π×cathode height (cm). In addition to continuous flowing of the current through the electrode, a pulse current may be used in which a current conduction stop period for setting the current value to zero (that is, no current conduction), and the current conduction period and the current conduction stop period are alternately repeated.

Also, the maximum voltage between the electrodes is not particularly limited, but from the viewpoint of suppressing impurity contamination, it may be, for example, 0.2 V or more and 3.5 V or less. The maximum voltage between the electrodes can be, for example, 1.0 V or more. From the viewpoint of power saving, the maximum voltage between the electrodes is preferably 3.0 V or less.

(Temperature of Chloride Bath)

The temperature of the chloride bath Bf may be changed as needed depending on the components in the chloride bath Bf. That is, the temperature of the chloride bath Bf may be appropriately determined from the viewpoints of maintaining the molten state of the chloride bath, eliminating energy loss due to excessive heating, and the like. In this case, it is also possible to appropriately determine the temperature of the chloride bath Bf with reference to the melting point of each metal chloride. The temperature of the chloride bath Bf is preferably 730° C. or more, and more preferably 750° C. or more, as the lower limit. Moreover, the temperature of the chloride bath Bf is preferably 900° C. or less, and more preferably 880° C. or less, as the upper limit.

The interior of the electrolytic bath 110 is typically controlled to an inert gas atmosphere, such as argon, from the viewpoint of suppressing an increase in the contents of impurities in the titanium-containing electrodeposit due to contamination of moisture in the atmosphere.

Next, as shown in FIG. 1(B), the anodes 120 are consumed as the anodes 120 containing titanium that has a higher ionization tendency than nickel is eluted into the chloride bath Bf to form a titanium-containing electrodeposit TC having a reduced impurity content on the surface of the cathode 130. The control mechanism then stops the current supply to terminate the electrodeposition.

The titanium-containing electrodeposit TC formed on the surface of the cathode 130 taken out from the electrolytic bath 110 is recovered by peeling it with a cutting tool or the like. The titanium-containing electrodeposit TC may be washed and dried as described below. The washing and drying may be performed together with the cathode 130 or may be performed after recovery from the cathode 130.

As an example, the cathode 130 is removed from the electrolytic bath 110, and the cathode 130 and the titanium-containing electrodeposit TC are washed with an acid and/or water to dissolve and remove the molten salt adhering thereto. The titanium-containing electrodeposit TC is peeled off from the surface of the cathode 130 with a cutting tool or the like. The titanium-containing electrodeposit TC is then placed in a container and vacuum-dried to evaporate moisture.

(Second Electrodeposition)

The titanium-containing electrodeposit can be further subjected to electrolysis to obtain a refined titanium-containing electrodeposit. By further refining the titanium-containing electrodeposit TC obtained in the first electrodeposition, a refined titanium-containing electrodeposit TP (titanium-containing electrodeposit) having a further reduced impurity content can be obtained. If the refined titanium-containing electrodeposit finally obtained in the third and subsequent electrodepositions is used as an electrode, the content of metal titanium can be further increased.

For example, as shown in FIG. 1(C), nickel baskets BK each having the titanium-containing electrodeposit TC as the anode 122 and a titanium cathode 130 are arranged in a chloride bath Bf. The control mechanism supplies current to the anodes 122 and the cathode 130 via electrically conductive lines EL connected to the baskets BK and the cathode 130, thereby performing the electrodeposition. The cathode 130 may be the same as the cathode 130 used in the first electrodeposition step, or may be replaced with a new cathode.

The composition of the chloride bath Bf, the temperature of the chloride bath, and the current density in the second electrodeposition may be the same as those in the first electrodeposition from the viewpoint of reducing aluminum and oxygen, and in this case, descriptions thereof will be omitted in order to avoid repeated explanation. In the second and subsequent electrodepositions, a chloride bath containing no titanium subchloride or containing less than 1 mol % of titanium subchloride may be used, or a molten salt bath having a different composition, such as a fluorine bath and an iodide bath may be used.

Next, as shown in FIG. 1(D), the titanium-containing anodes 122 are consumed as they are eluted into the chloride bath Bf to form a refined titanium-containing electrode deposit TP having a reduced impurity content on the surface of the cathode 130. The control mechanism then stops the current supply to terminate the electrodeposition.

The refined titanium-containing electrodeposit TP formed on the surface of the cathode 130 taken out from the electrolytic bath 110 is recovered by peeling it with a cutting tool or the like. The refined titanium-containing electrodeposit TP may be subjected to the washing and drying described above in the first electrodeposition. The washing and drying may be performed together with the cathode 130 or may be performed after recovery from the cathode 130.

This results in a refined titanium-containing electrodeposit.

In the embodiment shown in FIGS. 1(C) to (D), the second electrodeposition is performed once, but in order to further reduce the impurity content and further improve the purity of metal titanium, the electrodeposition may further be performed. More particularly, the resulting refined titanium-containing electrodeposit TP is placed in a nickel basket BK in the electrolytic bath 110, and the control mechanism supplies current between the refined titanium-containing electrodeposit TP as the anode and the titanium cathode 130, thereby performing the electrodeposition. Every time such an operation is repeated, it becomes possible to recover metal titanium in which the aluminum content and the oxygen content are more reliably reduced. However, from the viewpoint of production costs, the number of repetitions may be appropriately selected. For example, one or more and five or less, for example two or more and five or less electrodeposition steps are carried out. Also, for example, two or more and three or less electrodeposition steps are carried out.

(Composition of Refined Titanium-Containing Electrodeposit)

According to the second and subsequent electrodepositions, it is possible to obtain a refined titanium-containing electrodeposit having a controlled composition containing an aluminum content of 1000 ppm by mass or less, an oxygen content of 500 ppm by mass or less, a chlorine content of 500 ppm by mass or less, the balance being titanium and unavoidable impurities. These unavoidable impurities are often ore-derived impurities and chloride bath-derived components. The refined titanium-containing electrodeposit as used herein can be regarded as metal titanium in terms of the composition. Therefore, the refined titanium-containing electrodeposit is a metal titanium electrodeposit. The metal titanium electrodeposit has a low impurity content, for example, the total impurity content is 5000 ppm by mass or less, more preferably 3000 ppm by mass or less.

The upper limit of the aluminum content is, for example, 1000 ppm by mass or less, for example 100 ppm by mass or less, for example 50 ppm by mass or less. Also, the lower limit of the aluminum content is, for example, 5 ppm by mass or more, for example 10 ppm by mass or more.

The upper limit of the oxygen content is, for example, 500 ppm by mass or less, for example, 400 ppm by mass or less. Also, the lower limit of the oxygen content is, for example, 100 ppm by mass or more, for example 150 ppm by mass or more.

The upper limit of the chlorine content is, for example, 500 ppm by mass or less, for example, 300 ppm by mass or less, or, for example, 200 ppm by mass or less. Further, the lower limit of the chlorine content is, for example, 50 ppm by mass or more, for example, 100 ppm by mass or more. The refined titanium-containing electrodeposit can appropriately reduce the chlorine content even if it is produced through the electrodeposition in the chloride bath containing the large amount of titanium subchloride.

Further, in a further embodiment, when the above unavoidable impurities and the like are more specifically identified, it is also possible to obtain a refined titanium-containing electrodeposit having a further controlled composition of a nitrogen content of 0.03% by mass or less, a carbon content of 0.01% by mass or less, an iron content of 0.010% by mass or less, a magnesium content of 0.05% by mass or less, a nickel content of 0.01% by mass or less, a chromium content of 0.005% by mass or less, a silicon content of 0.001% by mass or less, a manganese content of 0.05% by mass or less and a tin content of 0.01% by mass or less.

The lower limit of the nitrogen content is, for example, 0.001% by mass or more, for example 0.002% by mass or more, for example 0.003% by mass or more. Also, the upper limit of the nitrogen content is, for example, 0.009% by mass or less, for example, 0.008% by mass or less.

The lower limit of the carbon content is, for example, 0.0004% by mass or more, for example 0.0006% by mass or more, for example 0.0008% by mass or more. Also, the upper limit of the carbon content is, for example, 0.008% by mass or less, for example, 0.004% by mass or less.

Also, the upper limit of the iron content is, for example, 0.005% by mass or less, for example, 0.003% by mass or less.

The upper limit of the magnesium content is, for example, 0.05% by mass or more, for example 0.01% by mass or less. Also, the lower limit of the magnesium content is, for example, 0.001% by mass or more, for example 0.005% by mass or more.

The upper limit of the nickel content is, for example, 0.008% by mass or less, for example, 0.004% by mass or less.

The lower limit of the chromium content is, for example, 0.0005% by mass or more, for example 0.001% by mass or more.

In addition, the lower limit of the manganese content is, for example, 0.001% by mass or more, for example, 0.005% by mass or more. Also, the upper limit of the manganese content is, for example, 0.03% by mass or less.

The upper limit of the tin content is, for example, 0.005% by mass or less, for example, 0.003% by mass or less.

It is assumed that various pure titanium products and titanium alloy products can be obtained at low cost by using the refined titanium-containing electrodeposit produced according to an embodiment of the present invention.

The method for measuring the impurity content of each component of the refined titanium-containing electrodeposit is the same as the method for measuring the impurity content of each component of the TiAlO conductive material as described above.

OTHER EMBODIMENTS

Other embodiments will be described below. In the embodiments described below, different points from the above embodiments will be mainly described. That is, the configurations described in the above embodiments can be appropriately applied to the following embodiments.

In the embodiments shown in FIGS. 1(A) to (D), the anodes and the cathode are arranged at approximately the same height, but the electrodeposition can be performed even if the arrangement of the anodes and the cathode is changed. As an example, an embodiment where the cathode is arranged on the upper side and the anode is arranged on the lower side will be described below. As shown in FIG. 2(A), in an electrolytic device 200, for example, a nickel base BS is placed on the bottom of an electrolytic bath 210, and a TiAlO conductive material as an anode 220 is placed on the base BS, and a titanium cathode 230 is placed at a higher position than the anode 220. The control mechanism then supplies current to the anode 220 and the cathode 230 via electrically conductive lines EL connected to the base BS and the cathode 230, thereby performing an electrodeposition (first electrodeposition).

Subsequently, as shown in FIG. 2(B), the anode 220 is consumed as the anode 220 is eluted into the chloride bath Bf to form a titanium-containing electrodeposit TC having a reduced impurity content on the surface of the cathode 230. The control mechanism then stops the current supply to terminate the electrodeposition.

The titanium-containing electrodeposit TC formed on the surface of the cathode 230 taken out from the electrolytic bath 210 is then recovered by peeling it with a cutting tool. It should be noted that the titanium-containing electrodeposit TC may be washed and dried as described above.

Subsequently, as shown in FIG. 2(C), the nickel base BS is placed on the bottom of the electrolytic bath 210 and the titanium-containing electrodeposit TC as the anode 222 are placed on the base BS, and the titanium cathode 230 is placed at a higher position than the anode 222. The control mechanism then supplies current to the anode 222 and the cathode 230 via the electrically conductive lines EL connected to the base BS and the cathode 230, thereby performing the electrodeposition (second electrodeposition).

Subsequently, as shown in FIG. 2(D), the anode 222 is consumed as the anode 222 containing titanium is eluted into the chloride bath Bf to form a refined titanium-containing electrodeposit TP having a reduced impurity content on the surface of the cathode 230. The control mechanism then stops the current supply to terminate the electrodeposition.

The cathode 230 is then taken out from the electrolytic bath 210, and the refined titanium-containing electrodeposit TP formed on the surface of the cathode 230 is washed, peeled, and dried to obtain a metal titanium electrodeposit.

The embodiment shown in FIGS. 3(A) to (D) is an embodiment where at least a part of the electrolytic bath is made of nickel and the portion made of nickel is used as the cathode. Further, it is an embodiment where the metal titanium electrodeposit can be produced without taking out the titanium-containing electrodeposit TC from the chloride bath Bf. As shown in FIG. 3(A), a nickel basket BK in which a TiAlO conductive material as an anode 320 is placed is arranged in an electrolytic device 300. In this case, by forming at least an inner wall of the electrolytic bath 310 from nickel, the inner wall serves as the cathode 330 during the electrodeposition. The control mechanism then supplies current to the anode 320 and the cathode 330 via the electrically conductive lines EL connected to the basket BK and the cathode 330, thereby performing the electrodeposition (first electrodeposition).

Subsequently, as shown in FIG. 3(B), the anode 320 is consumed as the anode 320 is eluted into the chloride bath Bf to form a titanium-containing electrodeposit TC having a reduced impurity content on the inner wall of the electrolytic bath 310. The control mechanism then stops the current supply to terminate the electrodeposition.

The nickel basket BK is then taken out from the chloride bath Bf.

Subsequently, as shown in FIG. 3(C), a titanium cathode 335 is placed in the chloride bath Bf. In this case, the titanium-containing electrodeposit TC formed on the inner wall surface of the nickel electrolytic bath 310 is used as the anode 322. The control mechanism then supplies current to the anode 322 and the cathode 335 via the electrically conductive lines EL connected to the inner wall of the electrolytic bath 310 and the cathode 335, thereby performing the electrodeposition (second electrodeposition).

Subsequently, as shown in FIG. 3(D), the anode 322 is consumed as the anode 322 is eluted into the chloride bath Bf to form a refined titanium-containing electrodeposit TP having a reduced impurity content on the surface of the cathode 335. The control mechanism then stops the current supply to terminate the electrodeposition.

The cathode 335 is then taken out from the electrolytic bath 310, and the refined titanium-containing electrodeposit TP formed on the surface of the cathode 335 is washed, peeled off, and dried to obtain a metal titanium electrodeposit.

Yet another embodiment is described in which the refined titanium-containing electrodeposit TP can be produced without removing the titanium-containing electrodeposit TC from the chloride bath Bf. As shown in FIG. 4(A), nickel baskets BK each having a TiAlO conductive material placed as an anode 420 are arranged in an electrolytic device 400. Two titanium cathodes 430 and 435 are then arranged side by side toward the center from the positions where the baskets BK are arranged. In this embodiment, the titanium cathode 430 preferably has a large number of holes having openings on the anode 420 side and the titanium cathode 435 side, in terms of efficiency of electrodeposition. The shapes of the holes are not particularly limited, and they may be through holes each having a linear cross section, or holes each having a complicated shape such as that of a porous body. The electrodeposition is then carried out by supplying electric current to the anodes 420 and the cathode 430 via the electrically conductive lines EL to the basket BK and the cathode 430 to which the control mechanism is connected (first electrodeposition).

Subsequently, as shown in FIG. 4(B), the anodes 420 are consumed as the anodes 420 are eluted into the chloride bath Bf to form a titanium-containing electrodeposit TC having a reduced impurity content on the surface of the cathode 430. The control mechanism then stops the current supply to terminate the electrodeposition.

Subsequently, as shown in FIG. 4(C), the cathodes 430 (see FIG. 4(B)) each having the titanium-containing electrodeposit TC formed on the surface is switched to the anodes 424, and the current is supplied to the anodes 424 whose control mechanism has been switched and the cathode 435 near the central portion, thereby performing the electrodeposition (second electrodeposition). In this case, the titanium-containing electrodeposit TC becomes the anode 422.

Subsequently, as shown in FIG. 4(D), the anodes 422 and optionally the anode 424 are consumed as they are eluted into the chloride bath Bf to form a refined titanium-containing electrodeposit TP having a reduced impurity content on the surface of the cathode 435. The control mechanism then stops the current supply to terminate the electrodeposition.

The cathode 435 is taken out from the electrolytic bath 410, and the refined titanium-containing electrodeposit TP formed on the surface of the cathode 435 is washed, peeled off, and dried to obtain a metal titanium electrodeposit.

An embodiment will be described in which multiple electrodeposition steps are continuously performed without taking out the titanium-containing electrodeposit TC from the chloride bath Bf and without changing the power supply connection. As shown in FIG. 5(A), an electrolytic device 500 is provided with a nickel basket BK in which a TiAlO conductive material as an anode 520 is placed, a titanium cathode 530, and a titanium bipolar electrode 540 at the center. Although the titanium bipolar electrode 540 is illustrated as being thick in FIG. 5(A), the titanium bipolar electrode 540 may be thin. The control mechanism supplies current to the anode 520 and the cathode 530 via the electrically conductive lines EL connected to the basket BK and the cathode 530, thereby performing the electrodeposition.

Subsequently, as shown in FIG. 5(B), the anode 520 is consumed as the anode 520 is eluted into the chloride bath Bf to form a titanium-containing electrodeposit TC having a reduced impurity content on the surface of the bipolar electrode 540. The formation of the titanium-containing electrodeposit TC on the bipolar electrode 540 corresponds to the first electrodeposition.

In addition, since the current is flowing between the anode and the cathode, the dissolution of the anode and the dissolution of the bipolar electrode can proceed at the same time. FIG. 5(C) shows that the cathode 530 side of the bipolar electrode 540 is eluted. In this embodiment, the bipolar electrode 540 will first elute titanium derived from the bipolar electrode 540 and then the titanium-containing electrodeposit TC.

Subsequently, as shown in FIG. 5(D), the bipolar electrode 540 and the titanium-containing electrodeposit TC are consumed to form a refined titanium-containing electrodeposit TP having a reduced impurity content on the surface of the cathode 530 (second electrodeposition). The current supply is then stopped in order to terminate the electrodeposition.

The cathode 530 is then taken out from the electrolytic bath 510, and the refined titanium-containing electrodeposit TP formed on the surface of the cathode 530 is washed, peeled off, and dried to obtain a metal titanium electrodeposit.

In FIG. 5(A), the titanium bipolar electrode is arranged. However, for example, the titanium-containing electrodeposit TC obtained by subjecting a TiAlO conductive material to the electrodeposition is arranged instead of the bipolar electrode, and the titanium-containing electrodeposit TC may be used as a bipolar electrode.

Alternatively, for example, after the titanium-containing electrodeposit TC is formed on the surface of the bipolar electrode 540 on the anode 520 side, a hook (not shown) attached to the upper end of the bipolar electrode 540 may be hooked with a hanging rod or the like to rotate the bipolar electrode 540 at 180 degrees. By doing so, the titanium-containing electrodeposit TC faces the cathode 530.

Although the above descriptions show that the bipolar electrode and the cathode are made of titanium, the material can be appropriately changed as long as the electrodeposit can be deposited. In addition, the bipolar electrode should have conductivity. Therefore, any non-conductive material such as ceramics cannot be used for the bipolar electrode.

As described above, the bipolar electrode may be non-movable or movable. Since electrodeposition and elution can occur simultaneously in the case of the non-movable bipolar electrode, it is preferable to have a large number of pores opening to the anode side and the cathode side. On the other hand, in the case of the movable bipolar electrode, electrodeposition and elution can proceed separately, so that the pores as described above are not necessary. Rather, elimination of the pores can avoid situations where the electrodeposit enters the pores and require a long period of time for elution.

As described above, the electrodeposition step has been described. The first and second electrodepositions can be carried out in combination as appropriate. For example, after carrying out the first electrodeposition according to the embodiment shown in FIGS. 1(A) and (B), the second electrodepositions according to the embodiment shown in FIGS. 2(C) and (D) can also be carried out.

(Sieving)

The produced titanium-containing electrodeposit, refined titanium-containing electrodeposit and metal titanium electrodeposit tend to have coarse grains. The particle size distribution of the titanium-containing electrodeposit is not particularly limited, but it is such that a ratio of particle sizes of the titanium-containing electrodeposit on the sieve when it is sieved through a 63 μm mesh sieve is, on a mass basis, for example, 25% or more, for example 50% or more, for example 70% or more, as a lower limit.

An example of the method for measuring the particle size distribution by sieving is shown below.

In a glove box in an argon atmosphere with an oxygen concentration of 5% by volume or less, the titanium-containing electrodeposit and the refined titanium-containing electrodeposit are cracked to the extent that they are not crushed or pulverized, and sieved using a sieve with an opening of 63 μm. As shown in the following equation (1), a mass (A1) of the titanium-containing electrodeposit (or the refined titanium-containing electrodeposit) on the sieve having an opening of 63 μm is divided by the total mass (Atotal) introduced into the sieve, and a ratio (a) is calculated as a percentage:


α(%)=A1/Atotal×100  Equation (2)

(Current Efficiency)

Although the current efficiency in the electrodeposition of the titanium-containing electrodeposit is not particularly limited, it is, for example, 20% or more, and preferably 40% or more, and more preferably 60% or more.

Also, the current efficiency in the electrodeposition of the refined titanium-containing electrodeposit is not particularly limited, but it is, for example, 20% or more, and preferably 40% or more, and more preferably 60% or more.

The amounts of electrodeposited materials generated and recovered during operation under respective current conduction amount conditions were totaled, and the current efficiency under each condition was calculated by the following equation (3):


Current efficiency(%)=(mass of titanium-containing electrodeposit(or refined titanium-containing electrodeposit)recovered from cathode/mass of theoretically generated titanium-containing electrodeposit (or theoretically generated refined titanium-containing electrodeposit))×100  Equation (3)

[2. Metal Titanium Electrodeposit]

The metal titanium electrodeposit according to the present invention corresponds to the refined titanium-containing electrodeposit or the like produced by the method for producing a titanium-containing electrodeposit described above, for example, and has a reduced impurity content. The metal titanium electrodeposit has a low impurity content, and, for example, the total impurity content is 5000 ppm by mass or less, for example 3000 ppm by mass or less. In an embodiment, the metal titanium electrodeposit has a composition having an aluminum content of 5 ppm by mass or more and 1000 ppm by mass or less, an oxygen content of 100 ppm by mass or more and 500 ppm by mass or less, a chlorine content of 500 ppm by mass or less, the balance being titanium and unavoidable impurities. These unavoidable impurities are often ore-derived impurities and chloride bath-derived components. The content of each of the above components can also be in the range described above in “Composition of Refined Titanium-Containing Electrodeposit”.

Also, in an embodiment, the above unavoidable impurities and the like may be more specifically identified. That is, the nitrogen content in the metal titanium electrodeposit may be 0.001% by mass or more and 0.03% by mass or less, and the carbon content may be 0.0004% by mass or more and 0.01% by mass or less, the iron content may be 0.010% by mass or less, the magnesium content may be 0.05% by mass or less, the nickel content may be 0.01% by mass or less, the chromium content may be 0.005% by mass or less, the silicon content may be 0.001% by mass or less, the manganese content may be 0.05% by mass or less, and the tin content may be 0.01% by mass or less. The content of each of the above components can also be within the range described above in “Composition of Refined Titanium-Containing Electrodeposit”.

The metal titanium electrodeposit is substantially granular when the appearance is visually observed, and when it is microscopically observed, it often has a three-dimensional shape in which dendritic or polyhedral fine grains are linked.

It should be noted that the method for measuring the impurity content of each component of the metal titanium electrodeposit is the same as the method for measuring the impurity content of each component of the TiAlO conductive material as described above.

EXAMPLES

The present invention will be specifically described based on Examples and Comparative examples. The descriptions of the following Examples and Comparative examples are merely experimental specific examples for facilitating the understanding of the technical content of the present invention, and the technical scope of the present invention is not limited by these specific examples.

[Evaluation of TiAlO Conductive Material]

First, the TiAlO conductive materials used in Examples and Comparative Examples described below were prepared by heating chemical blends including titanium ore containing titanium oxide, aluminum, and calcium fluoride as a separating agent under conditions as described below, followed by a post-process according to a known method (extraction step). The impurity content of each component of each measuring sample collected from the TiAlO conductive materials was measured by ICP emission spectrometry (PS3520UVDDII, manufactured by HITACHI) for metal components, by an inert gas fusion-infrared absorption method (TC-436AR, manufactured by LECO) for oxygen, by an inert gas fusion-thermal conductivity method (TC-436AR, manufactured by LECO) for nitrogen, by a combustion-infrared absorption method (EMIA-920V2, manufactured by Horiba, Ltd.) for carbon, and by silver nitrate titration method (GT-200, manufactured by Nittoseiko Analytech Co., Ltd.) for chlorine. This method for measuring the content of each component is also applied to the titanium-containing electrodeposit and the refined titanium-containing electrodeposit. The GD-MS measurement can also be used when the contents of impurities is extremely low. Further, a specific resistance of a separate measuring sample collected in the form of a 10 mm square block was measured by a two-terminal measurement method (low resistance meter 3566-RY, manufactured by Tsuruga Electric Corporation). These results are shown in Table 2. It should be noted that the titanium content of the TiAlO conductive material was 70% or more.

<Production Conditions for TiAlO Conductive Material>

Titanium ore: titanium oxide content of 95% by mass;

The molar ratio of the chemical blend was adjusted to be in the range of titanium oxide:aluminum:calcium fluoride (separating agent)=3:4-7:2-6;

Inert gas:argon gas; and

Heating temperature: in the range of 1500° C. to 1800° C.

TABLE 1 Al O N C Fe Mg Ni Cr Si Mn Sn Cl [% by [% by [% by [% by [% by [% by [% by [% by [% by [% by [% by [% by mass] mass] mass] mass] mass] mass] mass] mass] mass] mass] mass] mass] TiAlO 11.6 10.3 0.004 0.69 2.23 <0.001 <0.001 0.08 0.736 0.006 0.002 <0.007 Conductive Material

TABLE 2 Specific Resistance [Ω · m] TiAlO Conductive Material 5 × 10−5

[Production of Titanium-Containing Electrodeposit (First Electrodeposition)] Example 1

An electrolytic device 600 having the structure shown in FIGS. 6(A) and 7 was used. The dimensions and shape of the bath portion of the electrolytic bath 610 of the electrolytic device 600 were 300 mmΦ×570 mm in depth. Subsequently, 22 kg of potassium chloride and 17 kg of sodium chloride (50 mol %:50 mol % (Table 3)) was introduced into the electrolytic bath 610 of the electrolytic device 600 and dissolved to obtain a chloride bath Bf. Sponge titanium was then introduced into the chloride bath Bf, and the temperature of the chloride bath Bf was heated and maintained at 800° C. for 5 hours while bringing the sponge titanium with a titanium tetrachloride gas (sponge titanium:titanium tetrachloride=6:4 in the molar ratio). As a result, a titanium subchloride was generated in the chloride bath Bf (generation step). Before starting the electrodeposition, the concentration of the titanium subchloride in the chloride bath Bf was measured by the method as described above, indicating that the concentration was 3 mol %. In the table below, “Composition of Chloride Bath” indicates the composition before the generation of the titanium subchloride, and “Concentration of Titanium Subchloride” indicates the concentration in the chloride bath containing the titanium subchloride.

Annular nickel baskets BK each having an anode 620 made of 5000 g of TiAlO conductive material and having a large number of through holes were then arranged. A titanium round bar having a diameter 50 mm×300 mm was prepared as a cathode 630. The anodes 620 and the cathode 630 were arranged such that the height direction of each anode 620 and the cathode 630 was substantially parallel to the depth direction of the chloride bath.

The control mechanism supplied electric current to the anodes 620 and the cathode 630 via the electrically conductive lines EL connected to the anodes 620 and the cathode 630 to perform the electrodeposition in the chloride bath Bf. After seven hours from the start of the current supply, the control mechanism stopped the current supply. It should be noted that, as shown in FIG. 6(B), a titanium-containing electrodeposit TC deposited over the entire surface of the cathode 630 was obtained.

<Electrodeposition Conditions>

Interior of electrolytic bath: Ar gas atmosphere;

Temperature of chloride bath: 750° C.;

Current density: 0.4 A/cm2; and

Concentration of titanium subchloride in chloride bath: 3 mol %.

After stopping the current supply, the cathode 630 was pulled out of the electrolytic bath 610, and the cathode 630 and the titanium-containing electrodeposit TC were washed with water to remove adhering molten salts. The titanium-containing electrodeposit TC was peeled off from the cathode with a cutting tool and recovered. Moisture was removed from the titanium-containing electrodeposit TC by vacuum dryer.

Evaluation (1) Impurity Content

A measuring sample collected from the titanium-containing electrodeposit TC obtained by the electrodeposition was measured for the impurity content of each component by the method as described above. Then, a case where the oxygen content in the titanium-containing electrodeposit was 10,000 ppm by mass or less was evaluated as “good”, and other cases were evaluated as “poor”. The “good” is acceptable. The results are shown in Table 4. The balance other than the amounts of impurities shown in the table is the content of titanium.

(2) Ratio on Sieve

The ratio of the titanium-containing electrodeposit on the sieve was measured by the above-described sieving method (using a sieve having an opening of 63 μm). Then, a case where the ration on the sieve was less than 25% on a mass basis was determined to be “poor”, a case where the ratio on the sieve was 25% or more and less than 50% was determined to be “good”, a case where the ration on the sieve was 50% or more and less than 70% was determined to be “very good”, and a case where the ratio on the sieve was 70% or more was determined to be “excellent”. The “good”, “very good”, and “excellent” are acceptable. The results are shown in Table 4.

(3) Current Efficiency

The current efficiency was measured by the method as described above. Then, a case where the current efficiency was less than 20% by mass was determined to be “poor”, a case where the current efficiency was 20% or more and less than 40% was determined to be “good”, a case where the current efficiency was 40% or more and less than 60% was determined to be “very good”, and a case where the current efficiency was 60% or more was determined to be “excellent”. The “good”, “very good”, and “excellent” are acceptable. The results are shown in Table 4.

Examples 2 to 11, Comparative Examples 1 to 7

Each of Examples 2 to 11 and Comparative Examples 1 to 7 was carried out by the same method as that of Example 1, with the exception that the electrodeposition conditions were changed to those shown in Tables 3 and 5.

At the end of the electrodeposition, the resulting titanium-containing electrodeposit was washed with water and dried in a vacuum in the same manner as in Example 1, and the impurity content, the ration on the sieve and the current efficiency were then measured. The results are shown in Tables 4 and 6.

TABLE 3 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 First Composition of Chloride Bath 50% NaCl- 50% NaCl- 50% NaCl- 50% NaCl- 50% NaCl- 50% NaCl- Electrode (mol %) 50% KCl 50% KCl 50% KCl 50% KCl 50% KCl 50% KCl position Concentration of Titanium 3 6 11 11 11 11 Conditions Subchloride (mol %) Temperature of Chloride bath 750 750 750 850 750 750 (° C.) Current Density (A/cm2) 0.4 0.4 0.4 0.4 0.7 1.6 Maximum Voltage (V) 1.8 1.5 1.3 1.2 1.5 1.8 Electrodeposition time (hour) 7 7 7 7 7 7 Example 7 Example 8 Example 9 Example 10 Example 11 First Composition of Chloride Bath 100% MgCl2 100% MgCl2 100% MgCl2 100% MgCl2 100% MgCl2 Electrode (mol %) position Concentration of Titanium 3 11 11 11 11 Conditions Subchloride (mol %) Temperature of Chloride bath 750 750 850 850 850 (° C.) Current Density (A/cm2) 0.4 0.4 0.4 0.7 1.6 Maximum Voltage (V) 2.2 1.4 13 1.6 1.9 Electrodeposition time (hour) 7 7 7 7 7

TABLE 4 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Titanium- Impurity O Content (ppm by mass) 9,000 8,600 8,000 8,000 7,200 7,100 Containing Content Al Content (ppm by mass) 21,000 20,000 20,000 19,000 11,000 11,000 Electrodeposit Cl Content (ppm by mass) 100 100 90 <70 <70 <70 N Content (% by mass) 0.040 0.040 0.030 0.030 0.020 0.020 C Content (% by mass) 0.004 0.004 0.002 0.002 0.002 0.003 Fe Content (% by mass) 0.005 0.003 0.002 0.001 0.001 0.002 Mg Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Ni Content (% by mass) 0.010 0.008 0.002 0.002 0.002 0.080 Cr Content (% by mass) 0.020 0.010 0.010 0.020 0.010 0.030 Si Content (% by mass) 0.001 0.001 <0.001 <0.001 0.001 0.001 Mn Content (% by mass) 0.060 0.050 0.030 0.020 0.020 0.020 Sn Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Evaluation Results good good good good good good Particle Size Ration on Sleve (%) 28 35 50 55 68 70 (>63 μm) Evaluation Results good good very good very good very good excellent Production Current Efficiency (%) 25 30 37 40 55 53 Efficiency Evaluation Results good good good very good very good very good Example 7 Example 8 Example 9 Example 10 Example 11 Titanium- Impurity O Content (ppm by mass) 9,800 9,500 9,000 8,100 8,100 Containing Content Al Content (ppm by mass) 4,500 3,000 3,000 2,800 2,600 Electrodeposit Cl Content (ppm by mass) 100 <70 <70 <70 <70 N Content (% by mass) 0.050 0.020 0.030 0.020 0.020 C Content (% by mass) 0.002 0.004 0.003 0.003 0.002 Fe Content (% by mass) 0.001 0.002 0.001 0.001 0.001 Mg Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 Ni Content (% by mass) 0.020 0.002 0.002 0.005 0.008 Cr Content (% by mass) 0.010 0.020 0.020 0.010 0.010 Si Content (% by mass) 0.001 <0.001 <0.001 0.001 0.001 Mn Content (% by mass) 0.050 0.020 0.030 0.030 0.020 Sn Content (% by mass) <0.000 <0.001 <0.001 <0.001 <0.001 Evaluation Results good good good good good Particle Size Ration on Sleve (%) 40 70 80 87 88 (>63 μm) Evaluation Results good excellent excellent excellent excellent Production Current Efficiency (%) 31 66 73 76 75 Efficiency Evaluation Results good excellent excellent excellent Excellent

TABLE 5 Comparative Comparative Comparative Comparative Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 First Composition of Chloride Bath 50% NaCl- 50% NaCl- 50% NaCl- 100% MgCl2 100% MgCl2 100% MgCl2 100% MgCl2 Electro- (mol %) 50% KCl 50% KCl 50% KCl deposition Concentration of Titanium 0 11 11 0 11 11 0 Conditions Subchloride (mol %) Temperature of Chloride bath (° C.) 750 750 750 750 750 750 750 Current Density (A/cm2) 0.4 0.1 3.0 0.4 0.1 3.0 7.5 Maximum Voltage (V) 2.0 0.3 2.3 2.5 0.4 2.5 4.0 Electrodeposition time (hour) 7 20 7 7 20 7 7

TABLE 6 Compar- Compar- Compar- Compar- Compar- Compar- Compar- ative ative ative ative ative ative ative Example Example Example Example Example Example Example 1 2 3 4 5 6 7 Titanium- Impurity O Content (ppm by mass) 11,000 8,000 11,000 14,000 9,900 12,500 12,000 Containing Content Al Content (ppm by mass) 23,000 23,000 8,000 9,800 16,000 3,200 3,000 Electrodeposit Cl Content (ppm by mass) 100 150 <70 90 160 <70 90 N Content (% by mass) 0.080 0.009 0.008 0.010 0.008 0.007 0.007 C Content (% by mass) 0.003 0.001 0.002 0.003 0.002 0.002 0.002 Fe Content (% by mass) 0.005 0.002 0.002 0.006 0.003 0.002 0.005 Mg Content (% by mass) <0.001 <0.001 <0.001 0.010 0.005 0.006 0.009 Ni Content (% by mass) 0.007 0.003 0.050 0.080 0.003 0.080 0.130 Cr Content (% by mass) 0.010 0.020 0.020 0.030 0.010 0.020 0.020 Si Content (% by mass) <0.001 <0.001 0.001 0.001 <0.001 0.001 0.001 Mn Content (% by mass) 0.050 0.020 0.020 0.040 0.030 0.020 0.050 Sn Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Evaluation Results poor good poor pour good poor poor Particle Size Ration on Sieve (%) 8 40 15 10 43 19 38 (>68 μm) Evaluation Results poor good poor poor good poor good Production Current Efficiency (%) 15 10 35 17 12 38 50 Efficiency Evaluation Results poor poor good poor poor good very good

[Production of Refined Titanium-Containing Electrodeposit (Second Electrodeposition)] Example 1

In Example 1, a new chloride bath was prepared in the same manner as in the first electrodeposition, and the titanium subchloride was generated in the chloride bath Bf (generation step). Before starting the electrodeposition, the concentration of the titanium subchloride in the chloride bath Bf was measured by the method as described above, and as a result, it was 11 mol %. Subsequently, as shown in FIG. 6(C), ring shaped nickel baskets BK each having an anode 622 made of 500 g of titanium-containing electrodeposit TC (obtained in the first electrodeposition) and having a large number of through holes were then arranged. A titanium round bar having a diameter of 50 mm×300 mm was prepared as a cathode 630. In Table 7 below, “Composition of Chloride Bath” indicates the composition of the state before the generation of the titanium subchloride, and “Concentration of Titanium subchloride” indicates the concentration in the chloride bath containing the titanium subchloride.

It should be noted that the anodes 622 and the cathode 630 were arranged such that the height direction of each anode 622 and the cathode 630 was substantially parallel to the depth direction of the chloride bath.

The control mechanism supplied electric current to the anodes 622 and the cathode 630 via the electrically conductive lines EL connected to the anodes 622 and the cathode 630 to perform the electrodeposition in the chloride bath Bf under the electrodeposition conditions as shown in Table 7. After seven hours from the start of the current supply, the control mechanism stopped the current supply. Further, as shown in FIG. 6(D), a refined titanium-containing electrodeposit TP deposited over the entire surface of the cathode 130 was obtained.

<Electrolysis Conditions>

Interior of electrolytic cell: Ar gas atmosphere;

Temperature of chloride bath: 750° C.;

Current density: 0.4 A/cm2;

Concentration of titanium subchloride in chloride bath: 11 mol %.

After stopping the current supply, the cathode 630 was pulled out from the electrolytic bath 610, and the cathode 630 and the refined titanium-containing electrodeposit TP were washed with an acid and then washed with water to remove adhering molten salts. The refined titanium-containing electrodeposit TP was peeled off from the cathode 630 with a cutting tool and recovered. Moisture was evaporated from the refined titanium-containing electrodeposit TP by vacuum separation.

Evaluation (1) Impurity Content

A measuring sample collected from the refined titanium-containing electrodeposit TP obtained by the first electrodeposition was measured for the impurity content of each component by the method as described above. Then, a case where the oxygen content was 500 ppm by mass or less, the aluminum content was 1000 ppm by mass or less and the chlorine content was 500 ppm by mass or less in the refined titanium-containing electrodeposit was evaluated as “good”, and other cases were evaluated as “poor”. The results are shown in Table 8.

(2) Ratio on Sieve

The ratio of the refined titanium-containing electrodeposit on the sieve was measured by the above-described sieving method (using a sieve having an opening of 63 μm). Then, a case where the ration on the sieve was less than 25% on a mass basis was determined to be “poor”, a case where the ratio on the sieve was 25% or more and less than 50% was determined to be “good”, a case where the ration on the sieve was 50% or more and less than 70% was determined to be “very good”, and a case where the ratio on the sieve was 70% or more was determined to be “excellent”. The “good”, “very good”, and “excellent” are acceptable. The results are shown in Table 8.

(3) Current Efficiency

The current efficiency was measured by the method as described above. Then, a case where the current efficiency was less than 20% by mass was determined to be “poor”, a case where the current efficiency was 20% or more and less than 40% was determined to be “good”, a case where the current efficiency was 40% or more and less than 60% was determined to be “very good”, and a case where the current efficiency was 60% or more was determined to be “Excellent”. The “good”, “very good”, and “excellent” are acceptable. The results are shown in Table 8.

Examples 2 to 12

Each of Examples 2 to 11 was carried out by the same method as that of Example 1, with the exception that the electrodeposition conditions were changed to those shown in Table 7. In Example 12, which was separately set, the second electrodeposition was carried out by the same method as that of Example 9, with the exception that the titanium-containing electrodeposit TC obtained under the same conditions as those of the first electrodeposition in Example 9 was arranged in the basket BK, and the current density was changed to 0.7 A/cm2. Table 7 shows the maximum voltage and the electrodeposition time during the electrodeposition.

At the end of the electrodeposition, the resulting refined titanium-containing electrodeposit TP was washed with water and dried in a vacuum by the same method as that of the first electrodeposition, and the impurity content, the ratio on the sieve and the current efficiency were then measured. The results are shown in Table 8. Further, the shape of the refined titanium-containing electrodeposit TP obtained in Example 7 was confirmed by taking it by a camera. In order to confirm the shape of the refined titanium-containing electrodeposit TP, SEM observation was performed under the following measurement conditions. These results are shown in FIGS. 8(A) and (B). The refined titanium-containing electrodeposit was substantially granular when the appearance was visually observed, and when it was microscopically observed, it had a three-dimensional shape in which dendritic or polyhedral fine grains were linked.

<SEM Measurement Conditions>

SEM: model JSM-7800F, manufactured by JEOL;

Acceleration voltage: 10 kV; and

Magnifications: in range of 60 to 1000 times.

In Comparative Examples 1 to 7, the second electrodeposition was not performed because there were unacceptable evaluation results in the first electrodeposition.

TABLE 7 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Second Composition of Chloride Bath 50% NaCl- 50% NaCl- 50% NaCl- 50% NaCl- 50% NaCl- 50% NaCl- Electro- (mol %) 50% KCl 50% KCl 50% KCl 50% KCl 50% KCl 50% KCl deposition Concentration of Titanium 11 11 11 11 11 11 Conditions Subchloride (mol %) Temperature of Chloride bath 750 750 750 850 750 750 (° C.) Current Density (A/cm2) 0.4 0.4 0.4 0.4 0.7 1.6 Maximum Voltage (V) 1.3 1.3 1.2 1.1 1.3 1.7 Electrodeposition time (hour) 7 7 7 7 7 7 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Second Composition of Chloride Bath 100% 100% 100% 100% 100% 100% Electro- (mol %) MgCl2 MgCl2 MgCl2 MgCl2 MgCl2 MgCl2 deposition Concentration of Titanium 3 11 11 11 11 11 Conditions Subchloride (mol %) Temperature of Chloride bath 750 750 850 850 850 850 (° C.) Current Density (A/cm2) 0.4 0.4 0.4 0.7 1.6 0.7 Maximum Voltage (V) 1.9 1.3 1.2 1.4 1.8 1.4 Electrodeposition time (hour) 7 7 7 7 7 7

TABLE 8 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Refined Impurity O Content (ppm by mass) 400 400 300 300 200 200 Titanium- Content Al Content (ppm by mass) 900 800 800 700 600 600 Containing Cl Content (ppm by mass) <70 <70 <70 <70 <70 <70 Electrodeposit N Content (% by mass) 0.004 0.003 0.004 0.004 0.004 0.003 C Content (% by mass) 0.001 0.001 0.001 0.001 0.001 0.001 Fe Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Mg Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Ni Content (% by mass) 0.003 0.003 <0.001 <0.001 0.002 0.003 Cr Content (% by mass) 0.004 0.004 0.003 0.003 0.004 0.003 Si Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Mn Content (% by mass) 0.010 0.009 0.009 0.010 0.008 0.008 Sn Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Evaluation Results good good good good good good Particle Size Ration on Sieve (%) 79 84 88 90 95 95 (>68 μm) Evaluation Results excellent excellent excellent excellent excellent excellent Production Current Efficiency (%) 52 54 59 62 65 66 Efficiency Evaluation Results very good very good very good excellent excellent excellent Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Refined Impurity O Content (ppm by mass) 400 400 300 300 300 300 Titanium- Content Al Content (ppm by mass) 50 30 30 20 20 20 Containing Cl Content (ppm by mass) <70 <70 <70 <70 <70 <70 Electrodeposit N Content (% by mass) 0.008 0.004 0.003 0.004 0.004 0.003 C Content (% by mass) 0.004 0.001 0.001 0.001 0.001 0.001 Fe Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Mg Content (% by mass) 0.020 0.020 0.030 0.020 0.030 0.030 Ni Content (% by mass) 0.006 0.002 <0.001 0.003 0.004 0.003 Cr Content (% by mass) 0.003 0.004 0.004 0.004 0.003 0.004 Si Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Mn Content (% by mass) 0.010 0.008 0.010 0.009 0.009 0.009 Sn Content (% by mass) <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 Evaluation Results good good good good good good Particle Size Ration on Sieve (%) 88 93 95 96 96 95 (>68 μm) Evaluation Results excellent excellent excellent excellent excellent excellent Production Current Efficiency (%) 58 64 79 72 74 71 Efficiency Evaluation Results very good excellent excellent excellent excellent excellent

Discussion of Examples

In Examples 1 to 11, using a TiAlO conductive material having an aluminum content of 11.6% by mass and an oxygen content of 10.3% by mass, the oxygen content in the titanium-containing electrodeposit TC obtained by one electrodeposition could be reduced to 10000 ppm by mass or less. In Examples 1 to 11, the reason why the oxygen content could be reduced would be that the resulting titanium-containing electrodeposit was coarsened, and the oxygen content of the titanium-containing electrodeposit was reduced, in addition to the refinement effect by the electrodeposition. Examples 1 to 11 confirmed that it is useful to use a chloride bath containing 1 mol % or more of a titanium subchloride for electrodeposition, and to set the current density of the cathode to the range of 0.3 A/cm2 or more and 2.0 A/cm2 or less. In Examples 1 to 11, the oxygen content in the titanium-containing electrodeposit TC obtained by one electrodeposition was lower, so that it is also useful as a method for producing an additive to raw materials of titanium aluminum alloys, steel and the like. Also, according to Examples 1 to 11, the current efficiency was equal to or higher than the predetermined value, so it can be said that the production efficiency is also high. Moreover, it can be said that good refinement by the electrodeposition could be achieved without using the Kroll method. In addition, according to Examples 7 to 11, it was confirmed that the aluminum content could be further reduced by using a chloride bath containing magnesium chloride.

On the other hand, in Comparative Examples 1 to 7, at least one of the conditions where “the chloride bath contained 1 mol % or more of titanium subchloride” and “the current density of the cathode was in the range of 0.3 A/cm2 or more and 2.0 A/cm2 or less” was not satisfied. Therefore, Comparative Examples 1 to 7 would cause problems that the grain size could not be coarsened, the oxygen content in the titanium-containing electrodeposit could not be sufficiently reduced, and the current efficiency was reduced.

Further, it is considered that Examples 1 to 12 performed the electrodeposition multiple times, so that the oxygen content, aluminum content, and chlorine content in the purified titanium-containing electrodeposit TP could be more reliably reduced. In particular, it is considered that they performed the multiple electrodepositions where the chloride bath containing 1 mol % or more of the titanium subchloride was used, and the current density of the cathode was set to the range of 0.3 A/cm2 or more and 2.0 A/cm2 or less, so that the aluminum content and the chlorine content could be more reliably reduced.

DESCRIPTION OF REFERENCE NUMERALS

    • 100, 200, 300, 400, 500, 600 electrolytic device
    • 110, 210, 310, 410, 510, 610 electrolytic bath
    • 120, 122, 220, 222, 320, 322, 420, 422, 424, 520, 620, 622 anode
    • 130, 230, 330, 335, 430, 435, 530, 630 cathode
    • 540 bipolar electrode
    • Bf chloride bath
    • BK basket
    • BS base
    • EL electrically conductive line
    • TC titanium-containing electrodeposit
    • TP refined titanium-containing electrodeposit

It is to understand that the present invention also includes the following inventions:

[1]

A method for producing a titanium-containing electrodeposit, comprising an electrodeposition step of electrodepositing a titanium-containing electrodeposit in a chloride bath, the chloride bath being a molten salt, using an anode comprising a TiAlO conductive material containing titanium, aluminum, and oxygen, and a cathode,

Wherein, in the electrodeposition step, a current density of the cathode is in a range of 0.3 A/cm2 or more and 2.0 A/cm2 or less, and

    • wherein the chloride bath contains 1 mol % or more of a titanium subchloride.
      [2]

The method for producing a titanium-containing electrodeposit according to [1], wherein a temperature of the chloride bath is 730° C. or more.

[3]

The method for producing a titanium-containing electrodeposit according to [1] or [2], wherein the chloride bath contains 6 mol % or more of the titanium subchloride.

[4]

The method for producing a titanium-containing electrodeposit according to any one of [1] to [3], wherein the method comprises a generation step of generating the titanium subchloride by bringing metal titanium and titanium tetrachloride into contact with each other in a chloride bath, before the electrodeposition step.

[5]

The method for producing a titanium-containing electrodeposit according to any one of [1] to [3], wherein the method comprises a generation step of generating the titanium subchloride by bringing sponge titanium and titanium tetrachloride into contact with each other in a chloride bath, before the electrodeposition step.

[6]

The method for producing a titanium-containing electrodeposit according to any one of [1] to [5], further comprising an extracting step of heating a chemical blend comprising a titanium ore containing titanium oxide, aluminum, and a separating agent to obtain the TiAlO conductive material, before the electrodeposition step.

[7]

The method for producing a titanium-containing electrodeposit according to [6], wherein the separating agent comprises one or more selected from calcium fluoride, calcium oxide and sodium fluoride.

[8]

The method for producing a titanium-containing electrodeposit according to any one of [1] to [7], wherein a refined titanium-containing electrodeposit is obtained by performing multiple electrodepositions in the electrodeposition step.

[9]

The method for producing a titanium-containing electrodeposit according to [8], wherein the refined titanium-containing electrodeposit has an aluminum content of 1000 ppm by mass or less, an oxygen content of 500 ppm by mass or less, and a chlorine content of 500 ppm by mass or less.

The method for producing a titanium-containing electrodeposit according to [9], wherein the refined titanium-containing electrodeposit has:

    • a nitrogen content of 0.03% by mass or less;
    • a carbon content of 0.01% by mass or less;
    • an iron content of 0.010% by mass or less;
    • a magnesium content of 0.05% by mass or less;
    • a nickel content of 0.01% by mass or less;
    • a chromium content of 0.005% by mass or less;
    • a silicon content of 0.001% by mass or less;
    • a manganese content of 0.05% by mass or less; and
    • a tin content of 0.01% by mass or less.

A metal titanium electrodeposit,

    • wherein the metal titanium electrodeposit has an aluminum content of 5 ppm by mass or more and 1000 ppm by mass or less, an oxygen content of 100 ppm by mass or more and 500 ppm by mass or less, and a chlorine content of 500 ppm by mass or less.

The metal titanium electrodeposit according to [11], wherein the metal titanium electrodeposit has:

    • a nitrogen content of 0.001% by mass or more and 0.03% by mass or less;
    • a carbon content of 0.0004% by mass or more and 0.01% by mass or less;
    • an iron content of 0.010% by mass or less;
    • a magnesium content of 0.05% by mass or less;
    • a nickel content of 0.01% by mass or less;
    • a chromium content of 0.005% by mass or less;
    • a silicon content of 0.001% by mass or less;
    • a manganese content of 0.05% by mass or less; and
    • a tin content of 0.01% by mass or less.

Claims

1. A method for producing a titanium-containing electrodeposit, comprising an electrodeposition step of electrodepositing a titanium-containing electrodeposit in a chloride bath, the chloride bath being a molten salt, using an anode comprising a TiAlO conductive material containing titanium, aluminum, and oxygen, and a cathode,

wherein, in the electrodeposition step, a current density of the cathode is in a range of 0.3 A/cm2 or more and 2.0 A/cm2 or less, and
wherein the chloride bath contains 1 mol % or more of a titanium subchloride.

2. The method for producing a titanium-containing electrodeposit according to claim 1, wherein a temperature of the chloride bath is 730° C. or more.

3. The method for producing a titanium-containing electrodeposit according to claim 1, wherein the chloride bath contains 6 mol % or more of the titanium subchloride.

4. The method for producing a titanium-containing electrodeposit according to claim 1, wherein the method comprises a generation step of generating the titanium subchloride by bringing metal titanium and titanium tetrachloride into contact with each other in a chloride bath, before the electrodeposition step.

5. The method for producing a titanium-containing electrodeposit according to claim 1 wherein the method comprises a generation step of generating the titanium subchloride by bringing sponge titanium and titanium tetrachloride into contact with each other in a chloride bath, before the electrodeposition step.

6. The method for producing a titanium-containing electrodeposit according to claim 1, further comprising an extracting step of heating a chemical blend comprising a titanium ore containing titanium oxide, aluminum, and a separating agent to obtain the TiAlO conductive material, before the electrodeposition step.

7. The method for producing a titanium-containing electrodeposit according to claim 6, wherein the separating agent comprises one or more selected from calcium fluoride, calcium oxide, and sodium fluoride.

8. The method for producing a titanium-containing electrodeposit according to claim 1, wherein a refined titanium-containing electrodeposit is obtained by performing multiple electrodepositions in the electrodeposition step.

9. The method for producing a titanium-containing electrodeposit according to claim 8, wherein the refined titanium-containing electrodeposit has an aluminum content of 1000 ppm by mass or less, an oxygen content of 500 ppm by mass or less, and a chlorine content of 500 ppm by mass or less.

10. The method for producing a titanium-containing electrodeposit according to claim 9, wherein the refined titanium-containing electrodeposit has:

a nitrogen content of 0.03% by mass or less;
a carbon content of 0.01% by mass or less;
an iron content of 0.010% by mass or less;
a magnesium content of 0.05% by mass or less;
a nickel content of 0.01% by mass or less;
a chromium content of 0.005% by mass or less;
a silicon content of 0.001% by mass or less;
a manganese content of 0.05% by mass or less; and
a tin content of 0.01% by mass or less.

11. A metal titanium electrodeposit,

wherein the metal titanium electrodeposit has an aluminum content of 5 ppm by mass or more and 1000 ppm by mass or less, an oxygen content of 100 ppm by mass or more and 500 ppm by mass or less, and a chlorine content of 500 ppm by mass or less.

12. The metal titanium electrodeposit according to claim 11, wherein the metal titanium electrodeposit has:

a nitrogen content of 0.001% by mass or more and 0.03% by mass or less;
a carbon content of 0.0004% by mass or more and 0.01% by mass or less;
an iron content of 0.010% by mass or less;
a magnesium content of 0.05% by mass or less;
a nickel content of 0.01% by mass or less;
a chromium content of 0.005% by mass or less;
a silicon content of 0.001% by mass or less;
a manganese content of 0.05% by mass or less; and
a tin content of 0.01% by mass or less.
Patent History
Publication number: 20240191385
Type: Application
Filed: Apr 27, 2022
Publication Date: Jun 13, 2024
Inventors: Yuta Nakajo (Kanagawa), Kazuhiro Kumamoto (Kanagawa), Daisuke Suzuki (Kanagawa), Masashi Yamamoto (Kanagawa), Matsuhide Horikawa (Kanagawa), Hideki Fujii (Kanagawa)
Application Number: 18/569,131
Classifications
International Classification: C25D 3/56 (20060101); C22C 14/00 (20060101);