US20140262816A1

US20140262816A1 - Systems and methods for cobalt recovery

Info

Publication number: US20140262816A1
Application number: US13/802,000
Authority: US
Inventors: Nitin Goel; Ari Gabriel Partanen; Wayne W. Hazen; Phil Rooke
Original assignee: Freeport Mcmoran Corp
Current assignee: Freeport Minerals Corp
Priority date: 2013-03-13
Filing date: 2013-03-13
Publication date: 2014-09-18

Abstract

Various embodiments provide a method comprising leaching a cobalt bearing material to form a slurry, filtering the slurry to yield solids and a cobalt bearing liquid phase, performing a solution extraction of the cobalt bearing liquid phase to yield a purified cobalt bearing liquid phase, precipitating cobalt gypsum by adding lime to a first portion of the purified cobalt bearing liquid phase, and recycling the cobalt gypsum to the leaching.

Description

FIELD OF INVENTION

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 and other metal values.

BACKGROUND OF THE INVENTION

Cobalt 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.
In conventional processes, cobalt containing materials precipitated with magnesium oxide and subsequently leached are often difficult to filter during metal recovery. In addition, large volumes of aqueous solution are typically employed. More efficient systems and methods for cobalt recovery would be commercially and industrially advantageous.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides systems and methods for metal value recovery, such as cobalt recovery. In various embodiments, a method is provided comprising leaching a cobalt bearing material to form a slurry, filtering the slurry to yield solids and a cobalt bearing liquid phase, performing a solution extraction of the cobalt bearing liquid phase to yield a purified cobalt bearing liquid phase, precipitating cobalt gypsum by adding lime to a first portion of the purified cobalt bearing liquid phase, and recycling the cobalt gypsum to the leaching.
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.

BRIEF DESCRIPTION OF THE DRAWINGS

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:

FIG. 1 is a flow diagram illustrating an exemplary process in accordance with various embodiments of the present invention;

FIG. 2 is a flow diagram illustrating an exemplary process, including a leaching process, in accordance with various embodiments of the present invention;

FIG. 3 is a flow diagram illustrating an exemplary process, including an upstream bleed, in accordance with various embodiments of the present invention;

FIG. 4 is a flow diagram illustrating an exemplary process, including a source of the cobalt bearing material, in accordance with various embodiments of the present invention;

FIG. 5 is a flow diagram illustrating an exemplary process, including multiple sources of the cobalt bearing material, in accordance with various embodiments of the present invention; and

FIG. 6 is a flow diagram illustrating an exemplary process in accordance with various embodiments of the present invention.

DETAILED DESCRIPTION

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 funictions 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. Various embodiments of the present invention provide a process for recovering cobalt using, among other things, a precipitation and filtration process. These improved systems and methods disclosed herein achieve an advancement in the art by improving filtration, reducing acid volumes consumed, and improving recovery yields.
In particular, it has been discovered that a precipitation and filtration process, such as one using gypsum (e.g., calcium sulfate or CaSO₄), tends to, in various embodiments, improve filtration of cobalt bearing materials, increase cobalt recovery yield, and/or allow for an upstream bleed that reduces solution volumes in other processes.
In conventional processes, cobalt containing materials precipitated with magnesium oxide (MgO) and subsequently leached tend to be difficult to filter. It has been found that gypsum added via lime as a precipitant in one of the process stages tends to act as a filtering aid without such negative effects.
In conventional systems, large volumes of liquor having low cobalt concentrations are processed in various metallurgical processes, such as ion exchanges and solution extraction. Typically, these processes end in an electrowinning process that produces cobalt metal. However, it has been found that by placing a bleed after a filtration process, acid volumes used in downstream processes may be reduced. Thus, metal recovery processes may act on higher cobalt concentration liquors than in previous systems. Accordingly, cobalt recovery efficiency is enhanced, as well as reagent costs lessened.
While various embodiments of the present invention may be constructed and/or operated in any physical location, it is advantageous to operate various embodiments in close proximity to a primary metal 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. By operating in close proximity to a primary metal leaching operation, certain outputs of various embodiments may be forwarded to the primary leaching process. This allows metal content to be retained and further processed, decreasing net loss of metal, for example, by reducing the amount of metal sent to tails or residue.
With reference to FIG. 1, a metal recovery process 100 is illustrated according to various embodiments of the present invention. Metal recovery process 100 comprises subjecting cobalt bearing material (“Co MAT”) 102 to reactive process 104, filtration 106, and conditioning 108. A first portion of the output of conditioning 108 is sent to precipitation and filtration 112 and a second portion of the output of conditioning 108 is sent to further processing 110.
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 FIG. 1, after cobalt bearing material 102 has been suitably prepared, cobalt bearing material 102 may be subjected to reactive process 104 to put cobalt in cobalt bearing material 102 in a condition for later cobalt recovery steps. For example, exemplary suitable processes include reactive processes that tend to liberate the cobalt from cobalt bearing material 102. In accordance with various embodiments, reactive process 104 may comprise leaching.
Leaching may be any method, process, or system that enables cobalt to be leached from cobalt bearing material 102. Typically, leaching utilizes acid to leach cobalt from cobalt bearing material 102. SO₂and/or other suitable reducing agent may be added to reduce Co(III) to Co(II), as Co(II) is then readily soluble in the leach liquor. Basic (i.e., caustic) leaches may be used, however. For example, leaching can employ a leaching apparatus such as for example, a heap leach, a vat leach, a tank leach, a simultaneous grind-leach apparatus, a pad leach, a leach vessel or any other leaching technology, known to those skilled in the art or hereafter developed, that is useful for leaching cobalt from cobalt bearing material 102.
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.
In accordance with various embodiments, reactive processing step 104 may comprise any type of reactive process that is capable of yielding cobalt in cobalt bearing material 102 in a condition to be subjected to later metal recovery steps. In various embodiments, reactive processing 104 yields cobalt bearing reactive processed material 105, described in detail herein below.
Reactive processed material 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 reactive processed material 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 reactive processed material 105 comprises filtrate 107. Filtrate 107 is forwarded to conditioning 108.
In various embodiments, conditioning 108 may be for example, but is not limited to, a solid liquid phase separation step, an additional leach step, a pH adjustment step, a dilution step, a solution extraction step, a concentration step, an ion exchange step, a metal precipitation step, a filtering step, a settling step, and the like, as well as combinations thereof. In various embodiments, conditioning 108 may comprise a solution extraction separation step configured to selectively extract impurities from, as described in further detail herein.
In various embodiments, conditioning 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 comprises 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 reactive process 104.
Conditioned solution 116 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.
With reference to FIG. 2, metal recovery process 200 is illustrated. Metal recovery process 200 contains certain steps found in metal recovery process 100, but FIG. 2 illustrates an embodiment wherein reactive process 104 comprises leach 202 and wherein conditioning 108 (as illustrated in FIG. 1) comprises solution extraction 204.
Leach 202 comprises a leach process that is intended to liberate cobalt from CoMAT 102. Leach 202 comprises leaching CoMAT in the presence of acid and, in various embodiments, gypsum. The acid used in leach 202 may comprise, for example, sulfuric acid and/or hydrochloric acid. Leach 202 may be performed in a heap or a tank or other vessel. Leach 202 may be performed at temperatures above ambient temperatures, as further described herein. In various embodiments, additional reagents are added to leach 202. For example, sulfur dioxide may be introduced in leach 202. Sulfur dioxide addition acts to reduce cobalt III into cobalt II, which is more easily dissolved into solution.
In various embodiments, as described herein, leach 202 receives precipitated cobalt 114. Thus, at various times, leach 202 is performed in the presence of gypsum. Leach 202 produces leachate 203, which may be forwarded to filtration 106 to produce filtrate 205. It should be likewise noted that, at various times, leachate 203 comprises gypsum.
Solution extraction 204 may comprise any solution extraction process. In various embodiments, solution extraction 204 comprises a liquid-liquid extraction. During solution extraction 204, impurities from the filtrate 205 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, D2EPHA 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 204 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 entrained/extracted aqueous solution cobalt bearing solution from the organic phase. The washed 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. Conditioned solution 118 thus comprises cobalt containing liquid from solution extraction 204.
With reference to FIG. 3, metal recovery process 300 is illustrated. Metal recovery process 300 contains certain steps found in metal recovery process 200, but FIG. 3 illustrates an embodiment comprising upstream bleed 306. As described above, upstream bleed 306, which is located after a filtration process, tends to decrease downstream solution volumes. Thus, downstream metal recovery processes may act on lower volumes of solution than in previous systems. Accordingly, reagent cost and plant equipment cost tends to be lessened. Moreover, upstream bleed 306 acts as a bleed of impurities such as MgSO₄and Na₂SO₄from the circuit.
Upstream bleed 306 comprises a portion of filtrate 205. Upstream bleed 306 may be used to bleed a portion of filtrate 205 to precipitation and filtration 112, thus bypassing solution extraction 204. As discussed above, upstream bleed 306 allows for the reduction of impurities from the circuit and for the reduction in process volumes in downstream processing. For example, leachate 203 from leach 202 may be of relatively low cobalt concentration. Upstream bleed 306 provides a portion of the liquid phase of leachate 203 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 306 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.
Reagent 304 is added to precipitation and filtration 112 to aid in precipitation and filtration. In various embodiments, reagent 304 comprises lime, but may also comprise limestone slurry.
With reference to FIG. 4, metal recovery process 400 is illustrated. Metal recovery process 400 contains certain steps found in metal recovery process 300, but FIG. 4 illustrates an embodiment including a cobalt precipitation.
As discussed above, cobalt bearing material 102 may be produced in proximity to other metallurgical operations. For example, certain mining operations recover more than one metal from an ore body. Certain ore bodies comprise cobalt and copper, among other metals. Copper may be leached in a primary leaching operation. During the processing of the leachate from such a primary leaching operation, it may be beneficial to begin cobalt recovery.
Cobalt precipitation 402 may comprise any process by which cobalt is precipitated out of solution using a precipitant. 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. 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. Cobalt precipitation 402 may comprise multiple precipitation steps performed in parallel or in series. Product 401 of cobalt precipitation 402 may comprise cobalt bearing material 102.
With reference to FIG. 5, metal recovery process 500 is illustrated. Metal recovery process 500 contains certain steps found in metal recovery process 500, but FIG. 5 illustrates an embodiment including a dual cobalt precipitation.
The use of one precipitant over another is determined based on a number of factors. As discussed above, cobalt produced using magnesium oxide is generally considered of greater quality than cobalt produced using lime. Generally speaking, industrially produced cobalt hydroxide using magnesium is approximately 30%-45% pure, whereas industrially produced cobalt hydroxide using lime is approximately 10%-25% pure. Cobalt hydroxide is a commercially marketable product, so the desired return on investment may be weighed using the present or predicted market price of both materials. Thus, it may be beneficial in operations that produce both products to adjust the balance of the type and amount of cobalt hydroxide that is recovered and the type and amount of cobalt hydroxide that is marketed directly.
Reagent 502 may comprise magnesium oxide. Reagent 502 may be added to cobalt precipitation I 504 to precipitate cobalt as cobalt hydroxide. Reagent 506 may comprise lime. Reagent 506 may be added to cobalt precipitation II 508 to precipitate cobalt as cobalt hydroxide. The precipitated cobalt hydroxide may be mixed to form cobalt bearing material I.
With reference to FIG. 6, metal recovery process 600 is illustrated. Metal recovery process 600 contains certain steps found in metal recovery process 500, but FIG. 6 illustrates an embodiment including electrowinning to recover cobalt metal.
Cobalt precipitation 602 may comprise any process by which cobalt is precipitated out of solution using a precipitant. In cobalt precipitation 602, 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. Cobalt precipitation 602 may comprise multiple precipitation steps performed in parallel or in series. Cobalt precipitation 602 yields precipitated cobalt bearing material 603
Precipitated cobalt bearing material 603 is forwarded to leach 604. Leach 604 is conducted in acid media under the addition of sulfur dioxide gas. Sulfur dioxide addition acts to reduce cobalt III into cobalt II, which is readily dissolved into solution. Leach 604 may be performed under pressure and at temperatures above 25° C., though in various embodiments, leach 604 is conducted at atmospheric pressure and at a temperature of about 50° C. Leach 604 yields a leachate that is forwarded to leach residue filtration 608.
Leach residue filtration 608 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 610, is believed to act as a filtering aid in leach residue filtration 608. Leach residue filtration 608 produces solids 630. Solids 630 may be forwarded to, for example, a primary leaching process. In that regard, residual metals in solids 630, such as copper and cobalt, may be recovered. In various embodiments, solids 630 are sent to residue and/or neutralization 628. Neutralization 628 may comprise any suitable waste management or neutralization process. For example, lime may be added in neutralization 628 to regulate the pH of effluent prior to further processing.
The liquid portion of leach residue filtration 608 may be forwarded to Zn/MTn/Ca SX 606. Zn/Mn/Ca SX 606 comprises a solution extraction process that removes, among other tbigs, Zn, Mn, and Ca from the liquid portion of residue filtration 608. As discussed above, the aqueous liquid portion of leach residue filtration 608 may be contacted with an organic solution and an extractant. Zn/Mn/Ca SX 606 uses D2EHPA as an extractant. After impurities are brought in 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 270. The organic phase may be scrubbed with dilute sulfuric acid to strip any cobalt extracted from the aqueous phase. The scrubbed cobalt may then be sent back to precipitation and filtration 112. 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 606 produces may be referred to as extracted cobalt bearing solution 609.
Extracted cobalt bearing solution 609 is then subjected to organic polishing 614. Organic polishing 614 comprises a filtration of extracted cobalt bearing solution 609 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 609. For example, carbon media may adsorb organic compounds from extracted cobalt bearing solution 609. 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 614 that are suitable for adsorbing or absorbing organic compounds. Carbon media may periodically be regenerated or replaced to maintain appropriate adsorbing performance. Organic polishing 614 produces polished cobalt bearing solution 611.
Polished cobalt bearing solution 611 may be forwarded to copper ion exchange (Cu IX) 616. Copper may be present at relatively low concentrations in polished cobalt bearing solution 611. Copper present in polished cobalt bearing solution 611 may exist as copper I and/or copper II. Cu IX 616 may be used to remove copper. Copper removed by Cu IX 616 may be in either metal or ionic form. Ion exchange may be accomplished in any suitable manner. For example, polished cobalt bearing solution 611 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 609 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 616 produces exchanged cobalt bearing solution 613. 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 613 is subjected to organic polishing 618. Organic polishing 618 may be conducted in the same or similar manner as organic polishing 614. For example, exchanged cobalt bearing solution 613 may be contacted with a carton column to further remove impurities, such as organic compounds. Organic polishing 618 produces polished cobalt bearing solution 615.
Cobalt bearing solution 615 may be subjected to nickel ion exchange (Ni IX) 620. NiIX 620 may be accomplished in any suitable manner. For example, cobalt bearing solution 615 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 cobalt bearing solution 615 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 615 may also become bound to the surface or membrane. NiIX 620 produces purified cobalt bearing solution 617.
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 624 comprises a regeneration or purging of the membrane or surface of NiIX 620 to remove cobalt that may have adhered to the membrane or surface. In that regard, Co Elution 624 may comprise contacting an elution medium, such as an acid medium, with the membrane or surface. The elution medium may be conducted to leach 604 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 626 comprises a regeneration or purging of the membrane or surface of NiIX 620 to remove nickel that may have adhered to the membrane or surface. In that regard, Ni Elution 626 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 617 may be forwarded to electrowinning cell 622. Electrowinning cell 622 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 622 such that the anodes and cathodes are housed in separate compartments. For example, electrowinning cell 622 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 622 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 622 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.
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:

leaching a cobalt bearing material to form a slurry;

filtering the slurry to yield solids and a cobalt bearing liquid phase;

performing a solution extraction of the cobalt bearing liquid phase to yield a purified cobalt bearing liquid phase;

precipitating cobalt gypsum by adding lime to a first portion of the purified cobalt bearing liquid phase; and

recycling the cobalt gypsum to the leaching.

2. The method of claim 1, further comprising forwarding the solids to a second leaching operation.

3. The method of claim 1, further comprising bleeding a portion of the cobalt bearing liquid phase to the precipitating step.

4. The method of claim 1, further comprising forwarding the solids to tails.

5. The method of claim 1, wherein the cobalt bearing material comprises cobalt hydroxide.

6. The method of claim 5, wherein the cobalt hydroxide is formed by precipitating cobalt II with magnesia.

7. The method of claim 6, wherein the cobalt hydroxide is formed by precipitating cobalt II with lime.

8. The method of claim 1, further comprising subjecting a second portion of the purified cobalt bearing liquid phase to an additional conditioning step to yield a conditioned cobalt bearing liquid.

9. The method of claim 8, further comprising bleeding a portion of the conditioned cobalt bearing liquid to the precipitating step.

10. The method of claim 2, wherein the second leaching operation is a copper leaching operation.

11. The method of claim 8, further comprising electrowinning cobalt metal from a first portion of the conditioned cobalt bearing liquid.

12. The method of claim 11, wherein the electrowinning comprises a bagged anode process.

13. The method of claim 1, wherein the electrowinning comprises a free anode process.

14. The method of claim 11, wherein the electrowinning comprises depositing cobalt metal rounds on a masked cathode.

15. The method of claim 11, further comprising performing a cobalt selective solution extraction on a second portion of the conditioned cobalt bearing liquid to yield a refined cobalt containing liquid.

16. The method of claim 15, further comprising precipitating cobalt salt by adding a precipitating agent to the refined cobalt containing liquid.

17. The method of claim 16, wherein the precipitating agent comprises sodium carbonate.

18. The method of claim 8, wherein the additional conditioning step comprises eluting through a carbon column.

19. The method of claim 8, wherein the additional conditioning step comprises copper ion exchange.

20. The method of claim 8, wherein the additional conditioning step comprises nickel ion exchange.