SYSTEMS AND METHODS FOR RECOVERY OF COBALT METAL AND IONIC COBALT
Various embodiments provide a method comprising electrowinning a first portion of a conditioned cobalt bearing solution to yield cobalt metal, subjecting a second portion of a conditioned cobalt bearing solution to a first ion exchange to yield a second conditioned cobalt bearing solution, performing cobalt selective solution extraction on the second conditioned cobalt bearing solution to yield a refined cobalt containing liquid and, precipitating a cobalt salt by adding a precipitating agent to a first portion of the refined cobalt containing liquid.
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The present invention relates, generally, to systems and methods for recovering metal values from metal-bearing materials, and more specifically, to systems and methods for recovering cobalt in the forms of metallic cobalt and/or ionic cobalt.
BACKGROUND OF THE INVENTIONCobalt is an industrially important element that may be used in various catalysts, dyes, alloys, inks, battery additives, and other industrially beneficial products. Cobalt may be found in nature in a variety of forms and in a variety of ores. Cobalt containing ores include cobaltite, heterogenite (CoOOH), erythrite, glaucodot, and skutterudite. As found in nature, cobalt often exists in an oxidation state other than zero. For example, cobalt is often found in the form of cobalt II and cobalt III. Cobalt metal is commercially saleable, though purified forms of cobalt II and/or cobalt III, such as those in a salt form, are also commercially saleable.
In conventional processes, cobalt containing materials precipitated with magnesium oxide (MgO) and subsequently leached tend to be difficult to filter. In addition, large volumes of aqueous solution are typically employed. More efficient systems and methods for cobalt recovery would be commercially and industrially advantageous. In addition, it would be commercially and industrially advantageous to produce both cobalt metal and ionic cobalt.
SUMMARY OF THE INVENTIONAccordingly, the present invention provides systems and methods for metal value recovery, such as cobalt recovery. In various embodiments, a method is provided comprising electrowinning a first portion of a conditioned cobalt bearing solution to yield cobalt metal, subjecting a second portion of a conditioned cobalt bearing solution to a first ion exchange to yield a second conditioned cobalt bearing solution, performing cobalt selective solution extraction on the second conditioned cobalt bearing solution to yield a refined cobalt containing liquid, and, precipitating a cobalt salt by adding a precipitating agent to a first portion of the refined cobalt containing liquid.
In various embodiments, a system comprising an electrowinning cell configured to electrowin a first portion of a conditioned cobalt bearing solution to yield cobalt meta, an ion exchange column configured to subject a second portion of a conditioned cobalt bearing solution to a first ion exchange to yield a second conditioned cobalt bearing solution, a solution extraction circuit configured to perform cobalt selective solution extraction on the second conditioned cobalt bearing solution to yield a refined cobalt containing liquid and, a precipitation vessel configured to contain a cobalt salt formed by addition of a precipitating agent to a first portion of the refined cobalt containing liquid.
Further areas of applicability will become apparent from the detailed description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present invention.
The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present invention, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements and wherein:
The following description is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. The description of specific examples indicated in various embodiments of the present invention are intended for purposes of illustration only and are not intended to limit the scope of the invention disclosed herein. Moreover, recitation of multiple embodiments having stated features is not intended to exclude other embodiments having additional features or other embodiments incorporating different combinations of the stated features.
Furthermore, the detailed description of various embodiments herein makes reference to the accompanying drawing figures, which show various embodiments by way of illustration. While the embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that logical and mechanical changes may be made without departing from the spirit and scope of the present invention. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, steps or functions recited in descriptions any method, system, or process, may be executed in any order and are not limited to the order presented. Moreover, any of the step or functions thereof may be outsourced to or performed by one or more third parties. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component may include a singular embodiment.
The present invention relates, generally, to systems and methods for recovering metal values from metal-bearing materials, and more specifically, to systems and methods for recovering cobalt in the forms of metallic cobalt and/or ionic cobalt. Various embodiments of the present invention provide a process for recovering cobalt in both the metallic form and in a salt form (i.e., ionic form). Both metallic cobalt and ionic cobalt are commercially saleable. Ionic cobalt and metallic cobalt both have industrial uses.
It has been discovered that production of metallic cobalt and ionic cobalt may be conducted using an integrated process. In that regard, recovery of cobalt and ionic cobalt may be performed simultaneously, substantially simultaneously, serially, or at time independent of one another, in a manner that expedites recovery from a given feed stock of cobalt bearing materials. Stated another way, an integrated approach to the production of cobalt and ionic cobalt reduces the time and resources associated with cobalt recovery. In various embodiments, metallic cobalt and ionic cobalt may be recovered at the same facility or in separate facilities. In various embodiments, integrated recovery is advantageously combined with a bleed after a filtration process. Such a configuration may, for example, reduce solution volumes in the electrolyte of an electrowinning cell.
With reference to
Cobalt bearing material 102 may be an ore (cobaltite, heterogenite (CoOOH), erythrite, glaucodot, skutterudite, other cobalt containing ores, and mixtures of cobalt containing ores with ores bearing other metal values), a concentrate, a process residue, an impure metal salt, a preprocessed cobalt bearing material, combinations thereof, or any other material from which cobalt values are present. Cobalt, whether in metal or ionic form, may be recovered from cobalt bearing material 102 in accordance with various embodiments of the present invention. Various aspects and embodiments of the present invention, however, prove especially advantageous in connection with the recovery of cobalt from a preprocessed cobalt bearing material. A preprocessed cobalt bearing material may comprise a material that has been subjected to a prior metallurgical process. For example, a metallurgical process may result in the formation of cobalt hydroxide Co(OH)2. Cobalt hydroxide may be formed by combining a cobalt bearing material with magnesium oxide (MgO) and/or lime. It should be appreciated that a preprocessed cobalt bearing material may contain various other constituents as impurities or coprecipitates, such as copper, zinc, manganese and/or nickel. In various embodiments, cobalt bearing material 102 comprises cobalt hydroxide. In various embodiments, cobalt bearing material 102 comprises cobalt hydroxide produced by addition of magnesium oxide to a material containing cobalt ions. In various embodiments, cobalt bearing material 102 comprises cobalt hydroxide produced by addition of lime to a material containing cobalt ions. In various embodiments, cobalt bearing material 102 comprises cobalt hydroxide produced by addition of lime and/or magnesium oxide. Cobalt produced using magnesium oxide is generally considered of greater quality than cobalt produced using lime, though various factors, including reagent costs, may affect the selection of an appropriate cobalt bearing material.
With continued reference to
In accordance with various embodiments, leaching may be conducted at any suitable pressure, temperature, and/or oxygen content. Leaching can employ one of a high temperature, a medium temperature, or a low temperature, combined with one of high pressure, or atmospheric pressure. Leaching may utilize conventional atmospheric or pressure leaching, for example, but not limited to, low, medium or high temperature pressure leaching. As used herein, the term “pressure leaching” refers to cobalt recovery process in which material is contacted with an acidic or a basic solution and oxygen under conditions of elevated temperature and pressure. Medium or high temperature pressure leaching processes which are generally thought of as those processes operating under acidic conditions at temperatures from about 120° C. to about 190° C. or up to about 250° C.
Cobalt bearing leachate 105 may be directed to filtration 106. Filtration 106 may comprise any suitable filtration process. For example, vacuum filters such as a belt filter or disc filter may be used. In addition, pressure filters such as a plate and frame filter may be used.
Filtration 106 may separate the cobalt bearing leachate 105 into a solid phase and a liquid phase. The solid phase may be treated as residue. However, in various embodiments, the solid phase is sent to a primary leaching process. A primary leaching process may comprise a leaching process that is intended to liberate one or more metals from a metal bearing material. For example, in various embodiments, a primary leaching process comprises a leaching process to liberate copper and cobalt from a metal bearing material that comprises copper and cobalt. The liquid phase of cobalt bearing reactive processed material 105 comprises filtrate 107. Filtrate 107 is forwarded to solution extraction 108. Upstream bleed 120 is taken from filtrate 107.
In various embodiments, solution extraction 108 is configured to selectively extract impurities, as described in further detail herein. In various embodiments, solution extraction 108 comprises a liquid-liquid extraction. During solution extraction 108, impurities from the liquids phase may be loaded selectively into an organic phase in an extraction stage. Impurities may include one or more of copper, zinc, manganese and nickel. In various embodiments, the organic phase comprises an extracting agent, which may also be referred to as an extractant, to aid in transporting the impurities to the organic phase. For example, Di-(2-ethylhexyl)phosphoric acid (D2EHPA) may be used as an extracting agent. Cobalt is retained in the aqueous phase and Zn, Mn, and Ca are loaded in the organic phase.
The organic phase from solution extraction 108 may be then subjected to one or more wash stages and/or scrub stages in which the loaded organic phase is contacted with an aqueous phase in order to remove aqueous cobalt bearing solution droplets from the organic phase. However, in various embodiments, a wash stage is not included. The organic phase may then be subject to a solvent stripping stage, wherein the impurities are transferred to an aqueous phase. For example, more acidic conditions may shift the equilibrium conditions to cause the impurities to migrate to the aqueous phase. The aqueous phase, which contains the impurities, may be processed in a suitable manner. The organic phase is thus purged of impurities and, in various embodiments, may be contacted again with liquids from solid liquid phase. Conditioned solution 118 thus comprises cobalt containing liquid from solution extraction 108.
In various embodiments, solution extraction 108 produces conditioned solution 118 and conditioned solution 116. Conditioned solution 118 may be forwarded to precipitation and filtration 112, to precipitate any cobalt that was stripped from the organic phase in the wash/scrub stage.
Precipitation and filtration 112 may comprise a filtration process wherein a reagent is added to selectively precipitate cobalt. Precipitation and filtration 112 may comprise a precipitation that includes the use of a variety of precipitants, including, for example, calcium, lime (calcium hydroxide and/or calcium oxide), calcium carbonate and milk of lime (certain preparations of calcium hydroxide). In various embodiments, any suitable source of gypsum or lime may be used in precipitation and filtration 112. For example, lime may be added to precipitation and filtration 112 to precipitate cobalt as cobalt gypsum (“CoGyp”). Precipitation and filtration 112 thus produces precipitated cobalt 114. Precipitated cobalt 114 may be passed to leach 104.
Upstream bleed 120 comprises a portion of filtrate 107. Upstream bleed 120 may be used to bleed a portion of filtrate 107 to precipitation and filtration 112, thus bypassing solution extraction 108. As discussed above, upstream bleed 120 allows for the reduction of impurities from the circuit and for the reduction in process volumes in downstream processing. For example, leachate 105 from leach 104 may be of relatively low cobalt concentration. Upstream bleed 120 provides a portion of the liquid phase of leachate 105 to precipitation and filtration 112, allowing the cobalt to be precipitated and the cobalt-depleted liquid phase with the impurities to be sent to elsewhere (e.g., to tails). Stated another way, upstream bleed 120 acts to reduce solution volumes, in turn reducing the volume of solution that is subject to other metal recovery processes. By reducing volume prior to other processing steps, the volume of solution used in the other processing steps relative to the cobalt contained therein is lower than in conventional systems. Accordingly, process equipment may be downsized as the equipment need not be sized to accommodate a large volume of low cobalt concentration liquor. The reduction in equipment size is also a cost savings over conventional systems on a per mass unit of cobalt recovered basis.
Filtered solution 117 may be passed to further processing 110. Further processing 110 may comprise any metal recovery process, such as ion exchange, electrowinning, solution extraction, carbon column filtering, and combinations thereof. Further processing yields cobalt bearing solution 120.
A portion of cobalt bearing solution 120 may be sent to electrowinning 122. Electrowinning cell 122 yields a cobalt metal cathode product 128. As those skilled in the art are aware, a variety of methods and apparatus are available for the electrowinning of cobalt and other metal values, any of which may be suitable for use in accordance with the present invention, provided the requisite process parameters for the chosen method or apparatus are satisfied.
In various embodiments, electrowinning may be performed in electrowinning cell 122 such that the anodes and cathodes are housed in separate compartments. For example, electrowinning cell 122 may comprise a cathode compartment and an anode compartment. Compartments may be formed by the placement of a bag or other barrier, whether permeable or semi-permeable, around or partially around one or more of the anodes and cathodes. For example, a bag may be placed around all or a portion of an anode. Cobalt metal may evolve at the cathode. Manganese, among others species, may evolve at the anode. Manganese and other species from the anode may be forwarded to a leach or other metal recovery processing operation. Lean electrolyte from the anode compartment may be forwarded to leach 104.
In various embodiments, electrowinning may be performed in electrowinning cell 122 such that the anodes and cathodes are not separated into compartments. In such embodiments, the anodes and cathodes are placed in the same media without a barrier and electrical current is applied. For example, electrowinning cell 122 may comprise a cathode compartment and an anode compartment. Metal values, such as cobalt, may evolve at the cathode. Manganese, among others species, may evolve at the anode. Manganese and other species from the anode may be forwarded to a leach or other metal recovery processing operation. Lean electrolyte from the anode compartment may be forwarded to leach 104.
A portion of cobalt bearing solution 120, cobalt bearing subportion 130, may be forwarded to cobalt ion recovery 124. Cobalt ion recovery 124 may comprise any ionic cobalt recovery process, such as ion exchange, electrowinning, solution extraction, carbon column filtering, and combinations thereof. Cobalt ion recovery 124 yields ionic cobalt 126. Ionic cobalt 126 may be in a salt form, and, in various embodiments, may precipitate from aqueous solution. The ionic cobalt 126 may be dried and subject to further processing or sale.
With reference to
Cobalt bearing subportion 130 may be sent to conditioning 202. Conditioning 202 may comprise any suitable conditioning process or processes. For example, conditioning 202 may comprise solution extraction, ion exchange, precipitation, solid liquid phase separation, pH adjustment, dilution, filtering, flotation, and any other like operation.
Conditioned material 206 may be sent to precipitation 204. Precipitation 204 may comprise any process where cobalt is mixed with a precipitating agent to form a compound that has a low solubility in aqueous solution at room temperature (i.e., 25° C.) and atmospheric pressure.
A precipitant or precipitating agent, used herein interchangeably, is an agent that, when added to a solution, causes at least a portion of a solute to precipitate. A variety of precipitating agents may be used to precipitate metal values. Any agent that may precipitate a metal value from an aqueous solution may be used as a precipitating agent. Various carbonates, sulfites, sulphates, phosphates, hydroxides, oxides, and sulfides tend to have low solubility in aqueous solution. Precipitating agents may include various hydroxides and carbonates. More specifically, precipitating agents may include magnesium hydroxide, lime, magnesium oxide (also known in the art as magnesia), ammonium hydroxide, potassium hydroxide, calcium carbonate, ammonium sulphate, sodium carbonate, magnesium carbonate, potassium, and sodium hydroxide. In an exemplary embodiment, any form of magnesium oxide may be used as a precipitating agent. For example, forms of magnesium oxide include solid magnesium oxide, calcined magnesium oxide and slurried, calcined magnesium oxide.
Precipitation 204 may comprise the addition of a precipitating agent to conditioned material 206 in any suitable manner. The precipitating agent may be added continuously over time or may be added periodically. The solution may be agitated or otherwise mixed during precipitation. Solids, such as ionic cobalt 126, may be recovered by a solid liquid phase separation.
A solid liquid phase separation may be accomplished in any suitable manner, including use of filtration systems, counter-current decantation (CCD) circuits, thickeners, and the like. In various embodiments, a solid liquid phase separation may comprise further conditioning processes such as, for example, filtration or clarification in clarifiers, to remove fine solid particles. A variety of factors, such as the process material balance, environmental regulations, residue composition, economic considerations, and the like, may affect the decision whether to employ a CCD circuit, one thickener or multiple thickeners, one filter or multiple filters, and/or any other suitable device or combination of devices in a solid liquid separation apparatus. Ionic cobalt 126 may be dried after separation from the liquid phase of precipitation 204.
With reference to
Cobalt bearing material 102 is subject to leach 303. Leach 303 is conducted in acid media under the addition of sulfur dioxide gas, though any suitable reducing agent may be used in lieu of or with sulfur dioxide gas. Sulfur dioxide addition acts to reduce cobalt III into cobalt II, which is readily dissolved into solution. Leach 303 may be performed under pressure and at temperatures above 25° C., though in various embodiments, leach 203 is conducted at atmospheric pressure and at a temperature of about 50° C. Leach 303 yields a leachate that is forwarded to leach residue filtration 306.
Leach residue filtration 306 comprises the thickening and filtering of solids from liquids of the leachate. Gypsum, which may be present in the leachate due to, for example, precipitation and filtration 316, is believed to act as a filtering aid in leach residue filtration 306. Leach residue filtration 306 produces solids 322. Solids 322 may be forwarded to, for example, a primary leaching process. In that regard, residual metals in solids 322, such as copper and cobalt, may be recovered. In various embodiments, solids 322 are sent to residue and/or neutralization 320. Neutralization 320 may comprise any suitable waste management or neutralization process. For example, lime may be added in neutralization 320 to regulate the pH of effluent prior to further processing.
The liquid portion of leach residue filtration 306 may be forwarded to Zn/Mn/Ca SX 307. Zn/Mn/Ca SX 307 comprises a solution extraction process that removes, among other things, Zn, Mn, and Ca from the liquid portion of residue filtration 306. The aqueous liquid portion of leach residue filtration 306 may be contacted with an organic solution and an extractant.
Zn/Mn/Ca SX 307 uses D2EHPA as an extractant. After impurities are brought into the organic phase, the organic phase may be washed with water, though in various embodiments the organic phase is not washed. The organic phase may be scrubbed with dilute sulfuric acid to strip any cobalt that was extracted from the aqueous phase. After scrubbing, the dilute sulfuric acid, which now contains cobalt scrubbed from the organic phase, may be sent back to precipitation and filtration 112 via scrubbed cobalt solution 370. The organic phase may be stripped with an additional aqueous phase to bring impurities to the aqueous phase. The additional aqueous phase may be suitably treated. Acid for stripping the organic phase may be generated from other processes. The aqueous phase Zn/Mn/Ca SX 307 produces may be referred to as extracted cobalt bearing solution 309.
Extracted cobalt bearing solution 309 is then subjected to organic polishing 376. Organic polishing 376 comprises a filtration of extracted cobalt bearing solution 309 in a carbon column. A carbon column may comprise any suitable carbon media, such as, for example, activated charcoal, powdered activated carbon or granulated activated carbon. Carbon media may adsorb various impurities from extracted cobalt bearing solution 309. For example, carbon media may adsorb organic compounds from extracted cobalt bearing solution 309. Carbon media is suited for adsorption due to its high surface area, among other properties. In that regard, other media may be used in organic polishing 376 that are suitable for adsorbing or absorbing organic compounds. Carbon media may periodically be regenerated or replaced to maintain appropriate adsorbing performance. Organic polishing 376 produces polished cobalt bearing solution 311.
Polished cobalt bearing solution 311 may be forwarded to copper ion exchange (Cu IX) 308. Copper may be present at relatively low concentrations in polished cobalt bearing solution 311. Copper present in polished cobalt bearing solution 311 may exist as copper I and/or copper II. Cu IX 308 may be used to remove copper. Copper removed by Cu IX 308 may be in either metal or ionic form. Ion exchange may be accomplished in any suitable manner. For example, polished cobalt bearing solution 311 may be contacted with a surface or membrane containing ions. A surface or membrane in an ion exchange step may be comprised of a synthetic resin, a polymer, or any other suitable material. In various embodiments, for example, LEWATIT MONOPLUS TP207 resin, made by Lanxess of Birmingham, N.J. USA, is used. In further embodiments, PUROLITE S950 resin, made by Purolite, Inc. of 150 Monument Road, Bala Cynwyd, Pa. 19004, USA is used. Copper from cobalt bearing solution 311 may be exchanged with ions present on the surface or membrane, leaving copper present on the surface or membrane. The membrane or surface may be washed periodically to remove the adhered copper and increase efficacy of the ion exchange step. During such periodic washing, acid or other media may be contacted with the membrane or surface to remove the deposited copper ions. The acid or other media may be recycled into a primary leaching process to recover the copper ions washed off the membrane or surface. Cu IX 308 produces exchanged cobalt bearing solution 317. Copper removal could also be done with a suitable organic extractant using liquid liquid extraction, although in various embodiments, solvent extraction is not used for removing copper.
Exchanged cobalt bearing solution 317 is subjected to organic polishing 310. Organic polishing 310 may be conducted in the same or similar manner as organic polishing 376. For example, exchanged cobalt bearing solution 310 may be contacted with a carton column to further remove impurities, such as organic compounds. Organic polishing 310 produces polished cobalt bearing solution 319.
Polished cobalt bearing solution 319 may be subjected to nickel ion exchange (Ni IX) 312. NiIX 312 may be accomplished in any suitable manner. For example, polished cobalt bearing solution 319 may be contacted with a surface or membrane containing ions. A surface or membrane in an ion exchange step may be comprised of a synthetic resin, a polymer, or any other suitable material. In various embodiments, for example, DOWEX M4195 resin is used. DOWEX M4195 is made by the Dow Chemical Company, Dow Water Solutions, Customer Information Center, P.O. Box 1206, Midland, Mich. 48642-1206. In further embodiments, for example, DOWEX XUS43605 resin is used. DOWEX XUS43605 is made by the Dow Chemical Company, Dow Water Solutions, Customer Information Center, P.O. Box 1206, Midland, Mich. 48642-1206. Nickel from polished cobalt bearing solution 319 may be exchanged with ions present on the surface or membrane, leaving nickel present on the surface or membrane. In various embodiments, a portion of the cobalt in polished cobalt bearing solution 319 may also become bound to the surface or membrane. NiIX 312 produces purified cobalt bearing solution 374.
The membrane or surface may be washed periodically to remove the adhered cobalt and increase efficacy of the ion exchange step. For example, Co Elution 316 comprises a regeneration or purging of the membrane or surface of NiIX 312 to remove cobalt that may have adhered to the membrane or surface. In that regard, Co Elution 316 may comprise contacting an elution medium, such as an acid medium, with the membrane or surface. The elution medium may be conducted to leach 303 to improve cobalt recovery.
The membrane or surface may be washed periodically to remove the adhered nickel and increase efficacy of the ion exchange step. Ni Elution 318 comprises a regeneration or purging of the membrane or surface of NiIX 312 to remove nickel that may have adhered to the membrane or surface. In that regard, Ni Elution 318 may comprise contacting an elution medium, such as an acid medium, with the membrane or surface. The elution medium may be conducted to tails.
Purified cobalt bearing solution 374 may be forwarded to electrowinning cell 350. Electrowinning cell 350 yields a cobalt metal cathode product. As those skilled in the art are aware, a variety of methods and apparatus are available for the electrowinning of cobalt and other metal values, any of which may be suitable for use in accordance with the present invention, provided the requisite process parameters for the chosen method or apparatus are satisfied.
In various embodiments, electrowinning may be performed in electrowinning cell 350 such that the anodes and cathodes are housed in separate compartments. For example, electrowinning cell 350 may comprise a cathode compartment and an anode compartment. Compartments may be formed by the placement of a bag or other barrier, whether permeable or semi-permeable, around or partially around one or more of the anodes and cathodes. For example, a bag may be placed around all or a portion of an anode. Cobalt metal may evolve at the cathode. Manganese, among others species, may evolve at the anode.
In various embodiments, electrowinning may be performed in electrowinning cell 350 such that the anodes and cathodes are not separated into compartments. In such embodiments, the anodes and cathodes are placed in the same media without a barrier and electrical current is applied. For example, electrowinning cell 350 may comprise a cathode compartment and an anode compartment. Metal values, such as cobalt, may evolve at the cathode. Manganese, among others species, may evolve at the anode.
Subportion 352 of purified cobalt bearing solution 374 may be divided and subjected to manganese ion exchange (Mn IX) 354. Mn IX 354 may be accomplished in any suitable manner. For example, subportion 352 may be contacted with a surface or membrane containing ions. A surface or membrane in an ion exchange step may be comprised of a synthetic resin, a polymer, or any other suitable material. In various embodiments, for example, LEWATIT MONOPLUS TP207 resin, made by Lanxess of Birmingham, N.J. USA, is used. Manganese from subportion 352 may be exchanged with ions present on the surface or membrane, leaving manganese present on the surface or membrane. The membrane or surface may be washed periodically to remove the adhered manganese and increase efficacy of the ion exchange step. During such periodic washing, acid or other media may be contacted with the membrane or surface to remove the deposited manganese ions. The acid or other media may sent to neutralization 320 or other tails stream. Mn IX 354 produces exchanged cobalt bearing solution 356.
Exchanged cobalt bearing solution 356 may be subject to cobalt solution extraction 360. Solution extraction 360 may comprise any solution extraction process. In various embodiments, solution extraction 360 comprises a liquid-liquid extraction. During solution extraction 360, cobalt from exchanged cobalt bearing solution 356 may be loaded selectively into an organic phase in an extraction stage, wherein the organic phase comprises an extracting agent to aid in extracting cobalt to the organic phase and leaving impurities in the aqueous phase. For example, CYANEX 272 may be used as an extracting agent.
The organic phase from solution extraction 360 may be then subjected to one or more wash stages in which the loaded organic phase is contacted with an aqueous phase in order to remove entrained/extracted aqueous solution from the organic phase. The washed organic phase may then be subject to a solvent stripping stage, wherein the extracted cobalt is transferred to an aqueous phase. For example, more acidic conditions may shift the equilibrium conditions to cause the cobalt ions to migrate to the aqueous phase. Conditioned solution 362 thus comprises cobalt containing liquid from solution extraction 360, which may also be referred to as a cobalt loaded aqueous stream.
Conditioned solution 362 is subject to cobalt salt precipitation 368. Cobalt salt precipitation 368 comprises any suitable process for precipitating ionic cobalt in a salt form. In that regard, precipitating agent 366 may comprise any suitable agent for precipitating cobalt. For example, sodium carbonate may be used in various embodiments. Cobalt salt 370 may be separated from liquids 364 by any suitable means. For example, liquids 364 may be decanted away from cobalt salt 370 or, also for example, liquids 364 may be separated by filtration. Liquids 364 may be recycled to other processes, such as leach 303.
Cobalt salt 370 may be forwarded to cobalt salt handling 372. Cobalt salt handling 372 may comprise the quantifying and/or qualifying of cobalt salt 372. Stated another way, cobalt salt 372 may be tested for quality and/or packaged for sale. Cobalt salt handling 372 yields ionic cobalt 126.
With reference to
Raffinate 402 from electrowinning 350 may be sent to Mn IX 354. Raffinate 402 may comprise cobalt that was not deposited onto the cathode of electrowinning 350. The residual cobalt may be processed in Mn IX 354 and proceed to produce ionic cobalt 126.
It is believed that the disclosure set forth above encompasses at least one distinct invention with independent utility. While the invention has been disclosed in the exemplary forms, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. Equivalent changes, modifications and variations of various embodiments, materials, compositions and methods may be made within the scope of the present invention, with substantially similar results. The subject matter of the inventions includes all novel and non-obvious combinations and sub combinations of the various elements, features, functions and/or properties disclosed herein.
Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any element or combination of elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of any or all the claims or the invention. Many changes and modifications within the scope of the instant invention may be made without departing from the spirit thereof, and the invention includes all such modifications. Corresponding structures, materials, acts, and equivalents of all elements in the claims below are intended to include any structure, material, or acts for performing the functions in combination with other claim elements as specifically claimed. The scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given above.
Claims
1. A method comprising:
- electrowinning a first portion of a conditioned cobalt bearing solution to yield cobalt metal;
- subjecting a second portion of a conditioned cobalt bearing solution to a first ion exchange to yield a second conditioned cobalt bearing solution;
- performing cobalt selective solution extraction on the second conditioned cobalt bearing solution to yield a refined cobalt containing liquid; and,
- precipitating a cobalt salt by adding a precipitating agent to a first portion of the refined cobalt containing liquid.
2. The method of claim 1, wherein the precipitating agent comprises sodium carbonate.
3. The method of claim 1, wherein the ion exchange removes manganese from the conditioned cobalt bearing solution.
4. The method of claim 1, forwarding a second portion of the refined cobalt containing liquid to a cobalt gypsum precipitation process.
5. The method of claim 1, wherein the electrowinning comprises a bagged anode process.
6. The method of claim 1, wherein the electrowinning comprises a free anode process.
7. The method of claim 1, wherein the electrowinning comprises depositing cobalt metal rounds on a masked cathode.
8. A system comprising:
- an electrowinning cell configured to electrowin a first portion of a conditioned cobalt bearing solution to yield cobalt metal;
- an ion exchange column configured to subject a second portion of a conditioned cobalt bearing solution to a first ion exchange to yield a second conditioned cobalt bearing solution;
- a solution extraction circuit configured to perform cobalt selective solution extraction on the second conditioned cobalt bearing solution to yield a refined cobalt containing liquid; and,
- a precipitation vessel configured to contain a cobalt salt formed by addition of a precipitating agent to a first portion of the refined cobalt containing liquid.
9. The system of claim 8, wherein the precipitating agent comprises sodium carbonate.
10. The system of claim 8, wherein the ion exchange column further comprises resin configured to remove manganese from the conditioned cobalt bearing solution.
11. The system of claim 8, further comprising a channel configured to forward a second portion of the refined cobalt containing liquid to a cobalt gypsum precipitation process.
12. The system of claim 8, wherein the electrowinning cell comprises a bagged anode.
13. The system of claim 8, wherein the electrowinning cell comprises a free anode.
14. The system of claim 8, wherein the electrowinning cell comprises a masked cathode for the deposition of cobalt metal rounds.
Type: Application
Filed: Mar 13, 2013
Publication Date: Sep 18, 2014
Applicant: FREEPORT-MCMORAN CORPORATION (Phoenix, AZ)
Inventors: Nitin Goel (Tempe, AZ), Ari Gabriel Partanen (Tempe, AZ), Wayne W. Hazen (Lakewood, CO), Phil Rooke (Phoenix, AZ)
Application Number: 13/802,044
International Classification: C25C 1/08 (20060101); C25C 7/00 (20060101);
