Method for removing scandium and uranium from nickel- and cobalt-containing resources

Abstract

A process is provided as an efficient method for purifying nickel- and / or cobalt containing resources, including the steps of: i. leaching said material feed in an aqueous acidic medium, thereby obtaining an aqueous leachate; ii. precipitating iron, aluminium, uranium and scandium, if present, in said aqueous leachate by adding a phosphate compound; iii. separating the precipitate formed in step ii. from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron, aluminium, uranium and scandium, respectively. The solid obtained in step iii. is further leached to recover more nickel and / or cobalt, followed by a second stage of phosphate precipitation.

Description

[0001] METHOD FOR REMOVING SCANDIUM AND URANIUM FROM NICKEL- AND COBALT-CONTAINING RESOURCES

[0002] TECHNICAL FIELD

[0003] The present invention relates to the processing of nickel- and / or cobalt-containing resources to obtain aqueous salt solutions comprising nickel and / or cobalt with reduced uranium and / or scandium content, which can be used in various industries such as stainless-steel production, electroplating, and batteries.

[0004] INTRODUCTION

[0005] Uranium is a naturally occurring element that is often found in small concentrations in many types of rocks and that is commonly present in the feedstock used in the production of various metals. For instance, nickel and cobalt are often extracted from ores that also contain uranium. However, as uranium is a radioactive element, it is crucial to sequester it during the processing of nickel-containing raw materials to prevent potential harm to human health and the environment. Also, scandium is often present in ores that are used for nickel and cobalt extraction and is an undesired impurity in nickel and / or cobalt aqueous product salt solutions.

[0006] Therefore, developing efficient methods to remove or reduce the amount of uranium and scandium in nickel and cobalt-containing feedstocks is a critical area of research and development.

[0007] Currently, several methods are available for removing uranium and scandium from feedstocks, including precipitation, solvent extraction, ion exchange, and microbial processes. These methods can be effective but can also be expensive and complex, particularly in the case of solvent extraction and ion exchange, which require specialized equipment and reagents. Furthermore, the disposal of the resulting waste streams from these processes can also pose environmental challenges.

[0008] EP3034636A1 provides a method for processing a laterite-nickel ore and a method for recycling scandium. The method for recycling scandium includes steps of: extracting scandium from scandium-containing leachate with an organic extractant, so as toobtain a scandium-containing organic phase; subjecting the scandium-containing organic phase to back-extraction with a monovalent acid, so as to obtain a strip liquor; mixing the strip liquor with a precipitant, so as to obtain a scandium-containing precipitate; and calcining the scandium-contained precipitant, so as to obtain scandium oxide.

[0009] US2014314639A1 provides a method for recovering scandium from scandium-containing intermediate products, formed during hydrometallurgical processing of scandium-containing feed materials, including: (a) leaching of the scandium-containing intermediate products with a suitable acid at a controlled pH selected to maximize scandium extraction and minimize the co-extraction of impurities, (b) solid / liquid separation, to obtain a scandium-containing leach solution; (c) selective precipitation of the scandium at a controlled pH from the scandium-containing leach solution using a suitable base, (d) solid / liquid separation, to obtain an upgraded scandium concentrate and a barren solution for return to the hydrometallurgical process. A further upgraded scandium concentrate can be obtained by (e) alkaline leaching of the upgraded scandium concentrate for additional removal of impurities, and (f) solid / liquid separation to obtain a further upgraded scandium concentrate and impurities-con-taining base solution.

[0010] EP2907883A1 provides a method to effectively recover high-grade scandium from nickel oxide ores. The present invention includes a leaching step (SI) for charging nickel oxide ores and sulfuric acid into a pressurized vessel to cause solid-liquid separation of a leachate and a leaching residue under high temperature and high pressure, a neutralizing step (S2) for adding a neutralizing agent to the leachate to obtain a neutralized precipitate and a neutralized liquid, a sulfidizing step (S3) for adding a sulfidizing agent to the neutralized liquid to separate a nickel sulfide and a sulfidized liquid, an ion exchange step (S4) for bringing the sulfidized solution into contact with a chelate resin to adsorb Sc onto the chelate resin to obtain a Sc eluent, a solvent extraction step (S6) for bringing the Sc eluent into contact with an extracting agent to obtain a stripping solution, a Sc precipitation step (S7) for adding a neutralizing agent or oxalic acid to the stripping solution to obtain a precipitate, and a calcination step (S8) for drying and calcining the precipitate to obtain scandium oxide.

[0011] WO2010118455 provides a method for the treatment of mixed hydroxide product (MHP) produced in a metal extraction process such as a nickel extraction process. The method comprises the steps of treating the MHP with a first acid solution at a pHin the range of 4 to 8 as a first redissolution step and separating a first liquor formed in the first redissolution step from a first residue formed in this step. The method further comprises the step of treating the first residue with a second acid solution at a pH in the range of 0.5 to 4 as a second redissolution step. In this way, the impurities in the MHP may be selectively removed in the two redissolution steps. The first solvent extraction step is used for the quantitative removal of zinc, uranium as well as some calcium and manganese.

[0012] Such methods for removal of uranium and / or scandium from Ni and / or Co containing materials rely on separation of uranium or scandium from Ni and / or Co by solvent extraction, absorption on a chelate resin, or several (re)dissolution and precipitation steps at different pH. Such methods suffer from a loss of valuable nickel and / or cobalt atoms via the uranium and / or scandium precipitate, or require a high volume of expensive solvents and extractants needed for solvent extraction.

[0013] Therefore, there is a need for more effective, efficient, and sustainable methods for removing uranium and / or scandium from feedstocks. Such methods should be cost-effective, environmentally friendly, and produce minimal waste streams. In addition, the methods should be applicable to a wide range of feedstocks and applicable to different industries.

[0014] SUMMARY

[0015] The current invention provides in a solution for at least one of the above-mentioned problems by providing a method for efficient removal of uranium and / or scandium from nickel- and / or cobalt-containing resources to produce nickel and / or cobalt salt solutions.

[0016] Many sourced solid material feeds comprising nickel and / or cobalt comprise minor amounts of uranium and / or scandium. The present invention is advantageous because it provides a simple and efficient method for preparing an aqueous solution comprising nickel and / or cobalt that has a significantly reduced uranium and / or scandium content. The method involves a series of steps including leaching a solid material feed comprising nickel and / or cobalt and uranium and / or scandium with a mineral acid in an aqueous medium, increasing the pH of the leachate solution to precipitateiron, aluminium and partially scandium, if present, and adding a phosphate compound to form a uranium and / or scandium precipitate. Said uranium and / or scandium precipitate may still contain low amounts of the valuable nickel and / or cobalt. Therefore, said solid precipitate is further leached, to separate the remaining nickel and / or cobalt from uranium and scandium, again using a phosphate compound to facilitate precipitation of uranium and scandium. The nickel and / or cobalt recovered from the precipitate may be recirculated into the process.

[0017] The current invention for purifying a nickel- and / or cobalt-based feedstock including two steps of uranium and / or scandium removal via phosphate precipitation offers advantages over alternative methods only making use of solvent extraction, ion exchange, multiple precipitation steps without a phosphate compound, or only a single precipitation with a phosphate compound in several ways. Overall, the reagent cost decreases and recovery of nickel and / or cobalt increases by the current invention. Moreover, the method according to the current invention has the advantage that uranium and / or scandium only exits the process via the uranium and / or scandium precipitate that can be easily filtered and separated from the leachate, allowing for efficient recovery and further processing of uranium and / or scandium.

[0018] DESCRIPTION OF THE FIGURES

[0019] By means of further guidance, figures are included to better appreciate the teaching of the present invention. Said figures are intended to assist the description of the invention and are nowhere intended as a limitation of the presently disclosed invention.

[0020] The figures and symbols contained therein have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0021] Figure 1 shows a process according to the current invention.

[0022] Figure 2 shows a process according to the current invention.

[0023] Figure 3 shows a process according to the current invention.

[0024] Figure 4A shows a process according to the current invention.

[0025] Figure 4B shows a process according to the current inventionDETAILED DESCRIPTION OF THE INVENTION

[0026] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

[0027] As used herein, the following terms have the following meanings:

[0028] "A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

[0029] "About" as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / -20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -1% or less, and still more preferably + / -0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier "about" refers is itself also specifically disclosed.

[0030] "Comprise," "comprising," and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

[0031] The term "respectively" is used herein in combination with the expression "and / or". Hereby, the skilled person will know how to interpret the meaning of "and / or" in a specific context. In the context of the present invention, the term "respectively" refers to the correspondence between the presence of specific elements in the solid material feed and their resulting ions in the solution as it is understood by the skilled person from the context of the description. I.e., it means that if the solid materialfeed comprises uranium, the solution will contain uranium ions; if the solid material feed comprises scandium, the solution will contain scandium ions; and if the solid material feed comprises both uranium and scandium, the solution will contain both uranium ions and scandium ions; or that if the solid material feed comprises nickel, the solution will contain nickel ions; if the solid material feed comprises cobalt, the solution will contain cobalt ions; and if the solid material feed comprises both nickel and cobalt, the solution will contain both nickel ions and cobalt ions.

[0032] The term "a process for purifying a material feed" as used herein refers to the removal of at least in part uranium and / or scandium from said material feed. Further, also iron and / or aluminium, are at least in part removed via the inventive process. As a result of the purifying process, the concentration of nickel and cobalt in the resulting aqueous solution, relative to the total of nickel, cobalt, iron, aluminium, scandium and uranium in said solution, is higher than the concentration of nickel and cobalt in said material feed, relative to the total of nickel, cobalt, iron, aluminium, scandium and uranium in said material feed. Namely, the inventive process results in an aqueous product solution comprising nickel and / or cobalt in step iii. Said product solution contains at most 10 mg / L scandium, or at most 5 mg / L scandium, or at most 2 mg / L scandium or at most 1 mg / L scandium. Said product solution contains at most 10 mg / L uranium or at most 5 mg / L uranium, or at most 2 mg / L uranium or at most 1 mg / L uranium. Said product solution contains at most 10 mg / L iron, or at most 5 mg / L, or at most 1 mg / L iron. Said product solution contains at most 10 mg / L aluminium, or at most 5 mg / L aluminium, or at most 1 mg / L aluminium.

[0033] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints. All percentages are to be understood as percentage by weight, abbreviated as "wt.%" or as volume per cent, abbreviated as "vol.%", unless otherwise defined or unless a different meaning is obvious to the person skilled in the art from its use and in the context wherein it is used.

[0034] In the context of the present invention, the term "raw material feed" is to be considered synonymous to the term "solid material feed," or "solid material feedstock" or "feedstock" or "material feed" and refers to one or more feedstocks that comprise atleast one of uranium and scandium, and at least one of nickel and cobalt, and optionally manganese and / or lithium. Said metals may be included as such or may be included as a compound of the aforementioned metals, or as a mixture of compounds. In some embodiments, said raw material feed may comprise any one or combination of raw materials and recycled materials. Examples of raw materials include, but are not limited to, mixed hydroxide precipitates (MHP), nickel sulphide concentrate, cobalt sulphide concentrate, nickel laterite, nickel matte, or ferronickel. Examples of recycled materials include, but are not limited to, spent cathode material, and material derived from recycled lithium-ion batteries or lithium-ion battery manufacturing scrap, collectively, referred to herein as 'black mass'.

[0035] In the context of the present invention, the term "MHP" is to be considered as an abbreviation of the term "mixed hydroxide precipitate." Mixed hydroxide precipitate (MHP) is an intermediate product of nickel metallurgy that is often derived from processing laterite ores which contains primarily nickel and a minor amount of cobalt. It can also be produced from other sources, for example as a by-product from Ni recovery out of side streams from various metallurgical or mining operations. Alternatively or additionally, MHP may be obtained from nickel and / or cobalt containing hydroxide materials produced as production waste during preparation of cathode materials or obtained from battery recycling processes.

[0036] In the context of the present invention, the term "CHIP" is to be considered as an abbreviation of the term "cobalt hydroxide intermediate precipitate." Cobalt hydroxide intermediate is comprised primarily of cobalt, and typically has a cobalt content of 25 wt.% to 40 wt.%, relative to the total dry weight of said intermediate product. Typically, said CHIP comprises a significant amount of nickel. CHIPS are known to have a very low amount of impurities, which render them attractive for processes according to the present invention.

[0037] Said "solid material feed" may refer to a solid feed comprising an MHP product, a CHIP product, or a mixture of two or more MHP products, two or more CHIP products, or a mixture of one or more MHP products and one or more CHIP products. Preferably, said raw material feed comprises at least one nickel compound and at least one cobalt compound. Preferably, said nickel compound and said cobalt compound are comprised as a nickel(II) compound and as a cobalt(II) compound, respectively. Yet, saidnickel compound and said cobalt compound may also be comprised in higher oxidation states such as 3+ or 4+, or said metal-containing feed may comprise a mixture of nickel and / or cobalt compounds in oxidation state 2+ and in oxidation state 3 + and / or 4+. In addition, said raw material feed may comprise alloys of nickel (0) and cobalt (0), and / or said raw material feed may comprise one or more ores comprising nickel and cobalt.

[0038] Also, said solid material feed may comprise uranium and / or scandium and may comprise iron and / or aluminium and one or more impurities whereby said impurities comprise one or more selected from the list comprising Cu, Zn, Mn, Li, F, C, Ca, Si, P, As, Cd, Sb and Mg.

[0039] In the context of the present invention, the term "phosphate compound" refers to a chemical compound that contains a phosphate ion (PO43'), or a derivative thereof. Phosphate ions are anions with a central phosphorus atom that is bonded to four oxygen atoms. The group of phosphate compounds comprises phosphoric acid (H3PO4) and inorganic salts comprising HZPOT, HPO42' and / or PO43'. Examples of phosphate compounds are, but not limited to, phosphoric acid (H3PO4), sodium phosphate (Na3PO4), calcium phosphate (Ca3(PO4)2) and superphosphate (Ca(H2PO4)2'H2O).

[0040] In the context of the present invention, the term "continuous process" is to be considered as a process in which the produced solution has a substantially constant outflow and composition. Specifically, a continuous process is a process in which the produced solution has a constant composition within the range of what are considered normal process variations. More specifically, the produced solution has a composition wherein the concentration of each ingredient is within the range of + / -20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -3% or less of its average concentration. In a preferred embodiment, the present invention provides a continuous process which operates under steady-state conditions.

[0041] In the context of the present invention, the term "aqueous medium" is used for a water-based solution. The aqueous medium facilitates the handling of the contents of the reactor, such as mixing or pumping. The aqueous medium may already containsome of the other ingredients taking part in the reaction, orthose can be added later. Said aqueous medium may in particular contain the mineral acid.

[0042] The general inventive concept concerns a process for purifying a material feed comprising at least one of nickel and cobalt, at least one of uranium and scandium, and at least one of iron and aluminium, said process comprising the steps of:

[0043] i. leaching said material feed in an aqueous acidic medium, thereby obtaining an aqueous leachate;

[0044] ii. precipitating iron, aluminium, uranium and scandium, if present in said aqueous leachate, in the presence of a phosphate compound;

[0045] iii. separating the precipitate formed in step ii. from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium, and uranium and / or scandium, respectively.

[0046] Specifically, the process according to the general inventive concept further comprises an additional step, different from step ii., wherein iron, aluminium, uranium and scandium, if present, are precipitated from an aqueous solution in the presence of a phosphate compound. Subsequently, the precipitate of said additional step is separated from the aqueous medium thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium, and uranium and / or scandium, respectively.

[0047] The general inventive concept thus includes at least two stages of uranium and / or scandium removal via precipitation of uranium and / or scandium using a phosphate compound. Both precipitation steps may be executed by increasing the pH followed by addition of a phosphate compound, or the other way around.

[0048] The proposed method is relatively simple and straightforward, involving only a few steps to remove most of the uranium and / or scandium, namely leaching with a mineral acid, increasing pH, and adding a stoichiometric excess of a phosphate compound to precipitate uranium and / or scandium. Further, the proposed method is based on readily available materials such as mineral acids and phosphate compounds, making it a cost-effective solution.

[0049] The inventive process allows for selective separation of Sc and / or U from a Ni and / or cobalt materials with minimal Ni and Co losses and with minimal consumption of H3PO4 or other phosphate compounds. This is advantageous over alternative methodsonly making use of solvent extraction, ion exchange, or a single precipitation with a phosphate compound, or a single or multiple precipitations using other compounds such as ammonium carbonate or hydroxide. Namely, solvent extraction and ion exchange typically require the use of expensive organic solvents and resins, and they produce complex organic solutions or resins that require further processing to recover the valuable metals and the uranium for disposal, adding to the complexity and cost of these methods. On the other hand, removal of trace amounts of uranium and / or scandium via precipitation without a phosphate compound eventually leads to precipitation of valuable cobalt and or nickel atoms from the leaching solution. The method according to the current invention has the advantage that uranium and / or scandium only exits the process via the uranium and / or scandium precipitate that can be easily filtered and separated from the leachate, allowing for efficient recovery and further processing of uranium and / or scandium, respectively. Moreover, the uranium and / or scandium precipitation can be performed in an efficient way, limiting the required excess of phosphate compounds, because trace amounts of uranium and / or scandium are purified from the solution using two precipitation steps with a phosphate compound. Overall, the present invention provides a unique and effective process that minimizes the use of hazardous chemicals, maximizes the recovery of uranium, scandium, nickel and cobalt, and produces a nickel- and / or cobalt-rich solution with low uranium and scandium content.

[0050] The current invention, with reference to Figure 1, Figure 2, Figure 3 and Figure 4, describes a process for purifying a material feed comprising at least one of nickel and cobalt, at least one of uranium and scandium, and at least one of iron and aluminium, said process comprising the steps of:

[0051] i. leaching said material feed in an aqueous acidic medium, thereby obtaining an aqueous leachate;

[0052] ii. precipitating iron, aluminium, uranium and scandium, if present, in said aqueous leachate by adding a phosphate compound;

[0053] iii. separating the precipitate formed in step ii. from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium, and uranium and / or scandium, respectively;

[0054] whereby said process further comprises the steps of:al) subjecting said solid obtained in step iii. to acidification in an aqueous medium to dissolve nickel and / or cobalt compounds;

[0055] a2) precipitating iron, aluminium, uranium and scandium, if present, in the acidified aqueous solution obtained in step al) by adding a phosphate compound; and

[0056] a3) separating the precipitate formed in step a2) from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium and uranium and / or scandium, respectively;

[0057] and / or

[0058] bl) dividing the aqueous leachate of step i. in a first fraction and a second fraction, whereby said first fraction is processed in step ii . ; b2) precipitating iron, aluminium, uranium and scandium, if present, in said second fraction obtained in step bl) by adding a phosphate compound; and

[0059] b3) separating the precipitate formed in step b2) from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium and scandium and / or uranium.

[0060] The inventive process includes at least two stages of uranium and / or scandium removal via precipitation of uranium and / or scandium using a phosphate compound. That is, the precipitation of scandium and / or uranium occurs in step ii. and step a2), or in step ii. and step b2), or in step ii. and step a2) and step b)2.

[0061] In one embodiment, step ii. comprises the steps of:

[0062] ii. a. increasing the pH of the aqueous leachate obtained in step i., thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;

[0063] ii. b. adding a phosphate compound to the basified leachate solution obtained in step ii. a., thereby obtaining an uranium and / or scandium precipitate;

[0064] In one embodiment, step a2) comprises the steps of:a2) a. increasing the pH of the aqueous leachate obtained in step al), thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;

[0065] a2) b. adding a phosphate compound to the basified leachate solution obtained in step a2) a., thereby obtaining an uranium and / or scandium precipitate;

[0066] In one embodiment, step b2) comprises the steps of:

[0067] b2) a. increasing the pH of the aqueous leachate obtained in step bl), thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;

[0068] b2) b. adding a phosphate compound to the basified leachate solution obtained in step b2) a., thereby obtaining an uranium and / or scandium precipitate;

[0069] According to the invention, after leaching of the material feed in step i., in a first neutralization and phosphate precipitation step (step ii.) a precipitate is formed comprising iron and / or aluminium and uranium and / or scandium. In step ii. it is very important to ensure that each of those elements are removed to a maximal extent: By pH increase in step ii.a to a pH of at least 2.5, most of the iron, aluminium and also part of scandium may be precipitated. The higher the pH, the more scandium may be already precipitated. However, if the applied pH raise is too high, also cobalt and nickel may be found in the precipitate. On the other hand, precipitating part of scandium in step ii. a, decreases the amount of the phosphate compound to be added in step ii. b. Addition of a phosphate compound enables that scandium is precipitated without having to increase the pH to a too high value. Moreover, addition of a phosphate compound enables the precipitation of uranium.

[0070] Further, the inventive process may comprise a second neutralization step (step a2) a., step. b2) a.) and phosphate precipitation step (step a2)b ., step. b2) b.) to further separate nickel and cobalt from a solid, slurry or leachate that is already enriched in Fe, Al, U and Sc, meaning said solid, slurry or leachate has a higher Fe / (Ni + Co), AI / (Ni + Co), U / (Ni + Co), and Sc / (Ni + Co) ratio than the material feed provided in step i.

[0071] In one embodiment, at least a part of the solid obtained in step iii. is leached or redissolved in a second acidic aqueous medium in step al). Said solid may also be aslurry. This step al) is also called acidification. In one embodiment the solid or slurry obtained from step iii. is mixed and reacted with sulphuric acid at a pH of 2 or lower. Preferably, said second acidic aqueous medium has a pH of 2 or below. This causes nearly complete dissolution of any coprecipitated or undissolved Ni and / or Co in the solid, while also all other elements in said solid, including Fe, Al, Sc, U, will dissolve at least partially. For example, all or at least 50% of Al and Fe are redissolved. In this way Ni and / or Co is recovered from the cake and is not lost. After the acidification step, Si may be separated from the leachate. The obtained leachate in step al) is subjected to a second neutralization step (step a2) a.) and phosphate precipitation step (step. a2) b.).

[0072] In one embodiment, at least part of the solid obtained in step iii. is recirculated to the leaching step i.

[0073] In one embodiment, all of the solid obtained in step iii. is recirculated to the leaching step i.

[0074] In one embodiment, a second fraction of the leachate obtained in step i. is subjected to a second neutralization step (step b2)a.) and phosphate precipitation step (step b2)b.)

[0075] In the second neutralization step (step a2)a. or step b2)a.)) the pH is increased up to a lower value than in the first neutralization step, in order avoid any co-precipita-tion of Ni and / or Co with aluminium and iron. Next, both scandium and uranium are precipitated with high selectivity by addition of a phosphate compound (step a2)b. or step b2) b.)), and the precipitate is separated from the aqueous solution by filtration or decantation.

[0076] The aqueous solution or filtrate comprising Ni and / or Co obtained in step a3) or step b3) may be subjected to one or more further purification steps. In a preferred embodiment, said aqueous solution or filtrate comprising nickel and / or cobalt obtained in step a3) or step b3) is recirculated upstream in the process. Preferably, said solution is re-introduced in the process before step i. By implementation of this circulation loop, Sc and U can be removed completely in one single flowsheet without significant losses of Ni and Co.

[0077] Preferably, only the precipitate obtained from step a3) or b3) exits the process. The precipitate containing uranium and / or scandium may be subjected to a reduction process to recover the uranium and / or scandium. The reduction process can includeroasting the precipitate in air, followed by leaching with an acid to recover the uranium and / or scandium.

[0078] In a preferred embodiment, said phosphate compound is selected from the group consisting of H3PO4 and compounds comprising H PC ’, HPO42' or PO43'. The uranium and / or scandium precipitate is then filtered off from the leachate solution. If the precipitate containing iron and / or aluminium was not previously filtered off from the leachate solution, it can be filtered off together with the uranium and / or scandium precipitate. The process may be conducted in a single vessel, which simplifies the process and reduces costs. Preferably, the process is a continuous process. Alternatively, decantation is used to separate the precipitate from the leachate solution.

[0079] In a preferred embodiment, the pH of said aqueous leachate solution is increased in step ii. to between 2.5 and 6.0. In a preferred embodiment, the pH of said aqueous leachate solution is increased in step a2) to between 2.5 and 6.0. In a preferred embodiment, the pH of said aqueous leachate solution is increased in step b2) to between 2.5 and 6.0.

[0080] In a preferred embodiment, the pH of said aqueous leachate solution is increased in step ii. a) to between 2.5 and 6.0. In a preferred embodiment, the pH of said aqueous leachate solution is increased in step a2) a. to between 2.5 and 6.0. In a preferred embodiment, the pH of said aqueous leachate solution is increased in step b2) a. to between 2.5 and 6.0.

[0081] In a preferred embodiment, the pH in step ii. is increased by adding a Na base, Ca base, Ni base and / or Co base. In a preferred embodiment, the pH in step ii. is increased by adding MHP and / or CHIP. In a preferred embodiment, the pH in step ii. is first increased by adding MHP and / or CHIP, before further increasing the pH by adding a Na base, Ca base, Ni base and / or Co base.

[0082] In a preferred embodiment, the pH in step a2) is increased by adding a Na base, Ca base, Ni base and / or Co base. In a preferred embodiment, the pH in step b2) is increased by adding a Na base, Ca base, Ni base and / or Co base.

[0083] In a preferred embodiment, the pH in step ii. is increased by adding a Ca base and / or a Ni base. In a preferred embodiment, the pH in step a2) is increased by adding a Ca base and / or a Ni base. In a preferred embodiment, the pH in step b2) is increased by adding a Ca base and / or a Ni base.In a preferred embodiment, the precipitated iron and / or aluminium compounds in step ii. are not separated from the basified leachate solution prior to adding said phosphate compound. In a preferred embodiment, the precipitated iron and / or aluminium compounds in step a2) are not separated from the basified leachate solution prior to adding said phosphate compound. In a preferred embodiment, the precipitated iron and / or aluminium compounds in step b2) are not separated from the basified leachate solution prior to adding said phosphate compound.

[0084] In step ii. a, or step a2)a. or step b2 a), the pH of the aqueous solution or leachate solution obtained in the previous step, is increased to at least 2.5 by adding a base to the solution, thereby precipitating iron and / or aluminium and more preferably to a pH between 2.5 and 7.0 or between 3.0 and 6.0, and even more preferably between 2.5 and 5.0 or between 3.0 and 5.0, and most preferably at a pH of about 3.0, 3.5, 4.0, 4.5 or 5.0, or any value there in between. The base used can be any suitable inorganic or organic base, preferably an inorganic base selected from the group consisting of potassium hydroxide, potassium carbonate, nickel hydroxide, nickel carbonate, cobalt hydroxide, cobalt carbonate, manganese hydroxide, manganese carbonate, calcium hydroxide, calcium carbonate, sodium hydroxide, sodium carbonate, lithium hydroxide, lithium carbonate, magnesium oxide, magnesium hydroxide, magnesium carbonate, or a combination of two or more of the aforementioned. More preferably, said base is NaOH, KOH, Ca(OH)2, or NiCOs, or a combination thereof. The pH may be increased by adding a Ca base and / or a Ni base. The preferred bases are Ca(OH)2and NiCOs. The precipitate containing iron and / or aluminium can be optionally filtered off from the leachate solution or separated by decantation.

[0085] The aqueous solution or filtrate comprising nickel and / or cobalt obtained in step a3) or step b3), after precipitation and separation, may still comprise phosphate compounds. In a preferred embodiment, said aqueous solution or filtrate obtained in step a3) or step b3) comprises dissolved phosphate compounds in a total amount corresponding to 0 to 9000 mg / L of PO4, or in an amount of 10 to 4000 mg / L of PO4, or in an amount of 10 to 3000 mg / L of PO4, or 10 to 2000 mg / L PO4, or 1000 to 2000 mg / L PO4. The concentration of phosphate compounds may be determined by standard analytical methods such as ion-chromatography.In a preferred embodiment, the stream obtained in step a3) or step b3) is recirculated to step ii. Thus, the stream obtained in step a3) or step b3) comprising phosphate compounds may also be used to add a phosphate compound to step ii. and thus, allow for uranium and / or scandium precipitation in step ii.

[0086] The ratio of moles of phosphate ions added in step a2) or step b2) over moles of phosphate ions added in step ii. may be more than 5, or more than 10, or more than 50. Preferably, said ratio is lower than 100. It is especially advantageous in view of process control to add an excess of phosphate compound in step a2) or b2) and using only the remaining amount of phosphate ions for the precipitation of U and / or Sc in step ii. This dosage strategy of the phosphate compound minimizes the loss of Ni and / or Co in the precipitate and maximizes the removal of impurities.

[0087] In an alternative embodiment, the stream obtained in step a3) or step b3) comprising phosphate compounds is recirculated to the pulping or leaching step i., and those phosphate compounds are finally added to step ii. where they allow for uranium and / or scandium precipitation in step ii.

[0088] In one embodiment, said aqueous leachate solution in step i. comprises a mineral acid selected from the group consisting of H2SO4, HCI and HNO3.

[0089] In step i., the solid material feed comprising uranium and / or scandium, at least one of nickel and cobalt, and at least one of iron and aluminium, is leached in a mineral acid selected from H2SO4, HCI, and HNO3 or mixtures thereof in an aqueous medium. Preferably, said mineral acid is H2SO4 or HCI, and more preferably, said mineral acid is H2SO4, because it allows for the straightforward formation of nickel sulphate and cobalt sulphate, respectively, and since sulphuric acid is more easily handled. Optionally, step i. may be performed in the presence of a phosphate compound selected from the group consisting of H3PO4 and compounds comprising H2PO4', HPO42', and PO43’.

[0090] The pH of the aqueous acidic medium for leaching in step i. may be below 2.5, or below 2, or below 1.

[0091] The leaching process in step i. can be performed at a temperature ranging from ambient to 100°C, preferably from 70 to 95°C, and at a pressure ranging from atmospheric to 10 bar, preferably from atmospheric to 5 bar.

[0092] In one embodiment, selective leaching of the material feed occurs in step i. In one embodiment, selective leaching is used to separate a MnC residue from the leachingsolution. Alternatively, non-selective leaching may be targeted in step i. whereby manganese mostly remains in the aqueous leachate.

[0093] The leaching process may be performed in the presence of a reducing agent to increase the leaching yield. The reducing agent can be selected from a variety of reducing agents, such as sulphur dioxide, hydrogen peroxide, hydrazine, and hydroxylamine.

[0094] In one embodiment, said aqueous medium solution in step al) comprises a mineral acid selected from the group consisting of H2SO4, HCI and HNO3.

[0095] In one embodiment, said aqueous solution comprising nickel and / or cobalt obtained in step iii. is subjected to solvent extraction. By solvent extraction, the Ni and / or Co is further purified from impurities, including any traces of uranium and / or scandium, if still present. Impurities such as manganese, calcium, zinc, copper and cadmium are selectively extracted to the organic phase over nickel and cobalt. Typical extractants that used are alkylphosphorus-based extractants such as tributyl phosphate or di(2-ethylhexyl) phosphoric acid (D2EHPA), or octylphenyl acid phosphate, carboxylic acid derivatives such as neodecanoic acid, tertiary or quaternary amines, such as / V / ZV-dioctyl-l-octanamine or mixtures of Tri C8-10 alkyl amines (Alamine 336) or N-Methyl-ZV / ZV / ZV-trioctylammonium chloride (Aliquat 336), or mixtures thereof, can be used. The term "alkylphosphorus-based extractant" is equivalent to "an extractant comprising an alkylphosphorus group." In one embodiment, said solvent extraction makes use of an alkylphosphorus-based extractant, preferably an alkylphosphoric acid and / or derivatives thereof.

[0096] In one embodiment, said material feed is comprising mixed hydroxide precipitate or cobalt hydroxide intermediate precipitate.

[0097] The feedstock used in the process may be any raw material that comprises uranium and / or scandium, at least one of nickel and cobalt, and at least one of iron and aluminium. The solid material feed material may contain 1 to 1000 ppm uranium, relative to the total dry weight of the solid material feed, or 1 to 100 ppm uranium, or 5 to 100 ppm uranium, or 10 to 70 ppm uranium.

[0098] The solid material feed may contain 1 to 5000 ppm scandium, relative to the total dry weight of the solid material feed, or 1 to 1000 ppm scandium, or 5 to 750 ppm, or 10 to 550 ppm scandium.The solid material feed typically contains at least 20 wt% of at least one of nickel and cobalt, relative to the total dry weight of the solid material feed, more preferably at least 25 wt%, even more preferably at least 30 wt%, and less than 60 %, more preferably less than 53 wt%.

[0099] The solid material feed typically contains at least 0.05 wt% of at least one of iron and aluminium, relative to the total dry weight of the solid material feed, more specifically at least 0.09 wt%, even more specifically at least 0.2 wt%, and less than 10 wt%. The solid material feed may comprise one or more other impurities whereby said impurities comprise one or more selected from the list comprising Cu, Zn, Mn, Li, F, C, Ca, Si, P, As, Cd, Sb and Mg.

[0100] The preferred feedstocks are mixed hydroxide precipitate (MHP) and cobalt hydroxide precipitate (CHIP).

[0101] In a preferred embodiment, said mixed hydroxide precipitate (MHP) contains 5 to 100 ppm U, relative to the total dry weight of said mixed hydroxide precipitate. In a preferred embodiment, said mixed hydroxide precipitate (MHP) contains 5 to 550 ppm Sc, relative to the total dry weight of said mixed hydroxide precipitate. In a preferred embodiment, said mixed hydroxide precipitate (MHP) contains 5 to 100 ppm U and 10 to 550 ppm scandium, relative to the total dry weight of said mixed hydroxide precipitate.

[0102] Preferably, said mixed hydroxide precipitate comprises nickel in an amount of 25 to 60 wt.%, relative to the total dry weight of said mixed hydroxide precipitate, preferably in an amount of 33 to 53 wt.%. Preferably, said mixed hydroxide precipitate comprises cobalt in an amount of at least 0.1 wt.%, relative to the total dry weight of said mixed hydroxide precipitate, preferably in an amount of at least 0.2 wt.%, and more preferably in an amount of 0.9 to 6.0 wt.%. Preferably, said mixed hydroxide precipitate comprises manganese in an amount of at least 0.001 wt.%, relative to the total dry weight of said mixed hydroxide precipitate, preferably in an amount of at least 0.01 wt.%, and more preferably in an amount of 0.1 to 7.0 wt.%. Preferably, said mixed hydroxide precipitate comprises carbon in an amount of 0.01 to 5.00 wt.%, relative to the total dry weight of said mixed hydroxide precipitate, more preferably in an amount of 0.01 to 3.00 wt.%, and more preferably in an amount of 0.01 to 1.00 wt.%. Preferably, said mixed hydroxide precipitate comprises zinc in an amount of 0.01 to 0.30 wt.%, relative to the total dry weight of said mixed hydroxide precipitate. Preferably, said mixed hydroxide precipitate comprises iron in an amountof 0.1 to 3.0 wt.%, relative to the total dry weight of said mixed hydroxide precipitate. Preferably, said mixed hydroxide precipitate contains 0.1 to 3.0 % Al, relative to the total dry weight of said mixed hydroxide precipitate. Preferably, said mixed hydroxide precipitate comprises water in an amount of 25 to 60 wt.%, relative to the total wet weight of said mixed hydroxide precipitate, preferably in an amount of 30 to 55 wt.%.

[0103] The inventive process is especially suitable for providing a concentrated nickel sulphate solution in step iii., i.e., an aqueous nickel sulphate solution having a nickel content of at least 60 g Ni / L, preferably at least 80 g Ni / L, and more preferably between 80 and 200 g Ni / L, or even between 90 and 175 g Ni / L and most preferably between 100 and 150 g Ni / L. Preferably, the nickel sulphate solution obtained in the inventive process is a nickel sulphate solution having a nickel content of between 110 and 140 g / L, more preferably between 120 and 140 g / L, and most preferably said nickel sulphate solution having a nickel content of about 130 g / L.

[0104] The inventive process is also suitable for providing a concentrated cobalt sulphate solution in step iii., i.e., an aqueous cobalt sulphate solution having a cobalt content of at least 60 g Co / L, preferably at least 80 g Co / L, and more preferably between 80 and 200 g Co / L, or even between 90 and 175 g Co / L and most preferably between 100 and 150 g Co / L. Preferably, the cobalt sulphate solution is a cobalt sulphate solution having a cobalt content of between 110 and 140 g / L, more preferably between 120 and 140 g / L, and most preferably said cobalt sulphate solution having a cobalt content of about 130 g / L.

[0105] In a preferred embodiment of the present invention, the process comprises one or more further solvent extraction steps or other purification steps to obtain nickel or cobalt salts with battery-grade purity, such solutions comprise at least 99 at.% Ni or Co, relative to the total amount of metals in said solution. Preferably, such a solution has at least 99.5 at.% Ni or Co, and more preferably at least 99.9 at.% Ni or Co.

[0106] Embodiment A, illustrated in Figure 1 and Figure 4A, concerns a process for purifying a material feed comprising at least one of nickel and cobalt, at least one of uranium and scandium, and at least one of iron and aluminium, said process comprising the steps of:

[0107] i. leaching said material feed in an aqueous acidic medium, thereby obtaining an aqueous leachate;ii. precipitating iron, aluminium, uranium and scandium, if present, in said aqueous leachate by adding a phosphate compound; and iii. separating the precipitate formed in step ii. from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid or slurry comprising iron and / or aluminium, and uranium and / or scandium, respectively.

[0108] Further in the process according to Embodiment A, at least part of said solid obtained in step iii. is subjected to acidification in an aqueous medium to dissolve the remaining nickel and / or cobalt compounds (step al). Said acidification may take place at a pH of 2 or below. Iron, aluminium, uranium and scandium, if present, in the acidified aqueous solution obtained in step al) are precipitated by adding a phosphate compound (step a2); and the precipitate formed in step a2) is separated from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium and uranium and / or scandium, respectively (step a3).

[0109] Leaching in step i. may occur at a pH of 2 or below. The pH of said aqueous leachate solution may be increased in step ii. and step a2) to between 2.5 and 6.0. The pH in step ii. and step a2) may be increased by adding a Na base, Ca base, Ni base and / or Co base.

[0110] The pH of the aqueous leachate obtained in step i. may be first increased in step ii. by adding a base (step ii.a.), before adding a phosphate compound to said basified leachate solution (step ii.b). It may not be necessary to separate the precipitated iron and / or aluminium compounds in step ii.a. from the basified leachate solution prior to adding said phosphate compound in step ii.b.

[0111] Alternatively, a phosphate compound may be added first to the aqueous leachate obtained in step i., before increasing the pH.

[0112] The pH may be first increased in step a2) by adding a base (step a2)a.), before adding a phosphate compound to said basified leachate solution (step a2)b). Alternatively, a phosphate compound may be added first to the acidified aqueous solution obtained in step al), before increasing the pH.

[0113] The process of embodiment A may be a continuous process.

[0114] The aqueous solution obtained in step iii. may be further purified via solvent extraction.A part of the solid or slurry obtained in step iii. may be recycled back to the leaching step (step i.)

[0115] The aqueous solution obtained in step a3) may be recirculated into the process, more preferably said solution is re-added before the leaching step, to the leaching step (step i.), and / or to the precipitation step (step ii .) ■ The aqueous solution obtained in step a3) may still comprise phosphate compounds when recirculated into the process before the leaching step, to the leaching step (step i.), and / or to the precipitation step (step ii.). This way of adding phosphate compounds to enable precipitation of U and / or Sc in step ii. might be sufficient to reach the desired low level of U and / or Sc in the aqueous solution obtained in step ii. In such embodiments, it may not be necessary to additionally add a pure solution of a phosphate compound in water to step ii.

[0116] Said phosphate compound may be selected from the group consisting of H3PO4 and compounds comprising HZPOT, HPO42' or PO43'.

[0117] Said aqueous leachate solution in step i. may comprise a mineral acid selected from the group consisting of H2SO4, HCI and HNO3.

[0118] Said material feed may comprise mixed hydroxide precipitate or cobalt hydroxide intermediate precipitate.

[0119] Embodiment B, illustrated in Figure 2, Figure 3 and Figure 4B, concerns a process for purifying a material feed comprising at least one of nickel and cobalt, at least one of uranium and scandium, and at least one of iron and aluminium, said process comprising the steps of:

[0120] i. leaching said material feed in an aqueous acidic medium, thereby obtaining an aqueous leachate;

[0121] ii. adding a phosphate compound to a first fraction of the aqueous leachate obtained in step i., thereby precipitating iron, aluminium, uranium and scandium, if present; and

[0122] iii. separating the precipitate formed in step ii. from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium, and uranium and / or scandium, respectively;

[0123] Said solid obtained in step iii. is returned to the leaching step i.Further, in the process according to embodiment B the aqueous leachate obtained in step i. is divided in two fractions (step bl). While a first fraction is processed in step ii a second fraction of the acidic leachate solution is subjected to step b2. Iron, aluminium, uranium and scandium, if present in said second fraction, are precipitated by adding a phosphate compound (step b2); and the precipitate formed in step b2) is separated from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium and uranium and / or scandium, respectively (step b3).

[0124] Leaching in step i. may occur at a pH of 2 or below. The pH of said aqueous leachate solution may be increased in step ii. and step b2) to between 2.5 and 6.0. The pH in step ii. and step b2) may be increased by adding a Na base, Ca base, Ni base and / or Co base.

[0125] The pH of the aqueous leachate obtained in step i. may be first increased in step ii. by adding a base (step ii.a.), before adding a phosphate compound to the basified leachate solution (step ii.b). The precipitated iron and / or aluminium compounds in step ii.a. may remain unseparated from the basified leachate solution prior to adding said phosphate compound in step ii.b. Alternatively, a phosphate compound may be added first to the aqueous leachate obtained in step i., before increasing the pH. The pH may be first increased in step b2) by adding a base (step b2)a.), before adding a phosphate compound to the basified leachate solution (step b2)b). Alternatively, a phosphate compound may be added first to the solution obtained from step bl), before increasing the pH.

[0126] The process of embodiment B may be a continuous process.

[0127] The aqueous solution obtained in step iii. may be further purified via solvent extraction.

[0128] The aqueous solution obtained in step b3) may be recirculated into the process, more preferably said solution is re-added before the leaching step, to the leaching step (step i.), and / or to the precipitation step (step ii.). The aqueous solution obtained in step b3) may still comprise phosphate compounds when recirculated into the process before the leaching step, to the leaching step (step i.), and / or to the precipitation step (step ii.). This way of adding phosphate compounds to enable precipitation of U and / or Sc in step ii. may be sufficient to reach the desired low level of U and / or Sc in the aqueous solution obtained in step ii. In those embodiments it may not benecessary to additionally add a pure solution of a phosphate compound in water to step ii. One such process is illustrated Figure 3.

[0129] Said phosphate compound may be selected from the group consisting of H3PO4 and compounds comprising H2PO4-, HPO42' or PO43'.

[0130] Said aqueous leachate solution in step i. may comprise a mineral acid selected from the group consisting of H2SO4, HCI and HNO3.

[0131] Said material feed may comprise mixed hydroxide precipitate or cobalt hydroxide intermediate precipitate.

[0132] EXAMPLES

[0133] The following examples are intended to further clarify the present invention and are nowhere intended to limit the scope of the present invention.

[0134] EXAMPLE 1

[0135] A continuous process is executed as depicted in Figure 1. A solid feed consisting of MHP product is mixed with water to create a slurry or pulp (pulping). In a first leaching step (leaching, step i.), a solid feed consisting of MHP product is leached in a reactor comprising water and sulphuric acid as a mineral acid, whereby a solution comprising uranium, scandium, aluminium, iron, silicon, nickel and cobalt is obtained. By selective leaching, manganese remains predominantly in the solid phase as MnO2and is separated from the leaching solution.

[0136] Next, in a first neutralisation step (neutralisation, step ii.) the pH of the solution is increased by adding an inorganic base and / or MHP pulp, leading to precipitation of iron, aluminium, silicon and at least a part of the scandium. In this first neutralisation step a phosphate compound (H3PO4) is added leading to additional precipitation of scandium and strongly improved precipitation of uranium. In this first neutralization step, also certain amounts of nickel and cobalt are precipitated. The precipitate is then filtered off (step i ii .) : A first part of it is sent back to the first leaching (leaching) step, and a second part of it is subjected to a second leaching step (acidification, step al). By circulation of part of the precipitate back to the first leaching step, at least the Fe, Al, U and Sc concentration in the main flow increases compared to the Fe, Al, U and Sc to Ni ratio in the MHP.In the second leaching step (acidification, step al), the solid or slurry obtained in the first neutralization step is mixed and reacted with sulphuric acid at a pH of 2 or lower, in order to solubilize nickel and cobalt to a maximum extent. Next in a second neutralization step (Fe, Al, Si-removal, step a2), iron and aluminium are precipitated by increasing the pH, and additionally a phosphate compound (H3PO4) is added to selectively precipitate uranium and scandium, rather than nickel and cobalt. The pH in the second neutralization step is lower than in the first one and thus precipitates more selectively Fe and Al compared to Ni and Co. The precipitate comprising iron, aluminium, scandium and uranium and silicon is separated from the solution (step a3). The obtained solution comprising nickel and cobalt is sent back to the pulping step.

[0137] EXAMPLE 2

[0138] A continuous process is executed as depicted in Figure 2. A solid feed consisting of MHP product is mixed with water to create a slurry or pulp (pulping). In a first leaching step (leaching, step i.), a solid feed consisting of MHP product is leached in a reactor comprising water and sulphuric acid as a mineral acid, whereby a solution comprising uranium, scandium, aluminium, iron, nickel and cobalt is obtained.

[0139] Next, in a first neutralisation step (neutralisation, step ii.) the pH of the solution is increased by adding an inorganic base and / or MHP pulp, leading to precipitation of iron, aluminium, and at least part of the scandium. H3PO4 is dosed in this step to facilitate the precipitation of scandium, and to precipitate also uranium in a strongly improved way. The obtained solid precipitate from the first neutralisation step is separated (step iii) and recycled to the selective leaching step, where it redissolves. An aqueous stream with increased Fe, Al, Sc and U to Ni ratios versus the feed material (leaching filtrate) is directed from the leaching step, to a side process (step bl) where the pH of said stream is increased so that Fe and Al are precipitated selectively compared to Ni and Co (step b2). During or after this step, H3PO4 is added so that also Sc and U are precipitated selectively compared to Ni and Co. The precipitate comprising iron, aluminium, scandium and uranium is separated from the solution (step b3).EXAMPLE 3

[0140] A continuous process is executed as depicted in Figure 3. A solid feed consisting of MHP product is mixed with water to create a slurry or pulp (pulping). In a first leaching step (leaching, step i.), a solid feed consisting of MHP product is leached in a reactor comprising water and sulphuric acid as a mineral acid, whereby a solution comprising uranium, scandium, aluminium, iron, nickel and cobalt is obtained.

[0141] Next, in a first neutralisation step (neutralisation, step ii.) the pH of the solution is increased by adding an inorganic base and / or MHP pulp, leading to precipitation of iron, aluminium, and at least part of the scandium. The precipitation of scandium and uranium is further facilitated by the presence of low amounts of phosphate compounds (around 60 mg / L PC ), that are added to the neutralization step via the filtrate of the 'Fe,AI removal step' (step b2).

[0142] The obtained solid precipitate from the first neutralisation step is separated (step iii) and recycled to the selective leaching step, where it redissolves. The solution obtained from step iii. contains < lmg / L Fe, < lmg / L Al, 2 mg / L Sc and 1 mg / L U. An aqueous stream with increased Fe, Al, Sc and U to Ni ratios versus the feed material (leaching filtrate) is directed from the leaching step, to a side process (step bl) where the pH of said stream is increased so that Fe and Al are precipitated selectively compared to Ni and Co (step b2). During or after this step, H3PO4 is added so that also Sc and U are precipitated selectively compared to Ni and Co. The precipitate comprising iron, aluminium, scandium and uranium is separated from the solution (step b3). The filtrate of step b2 containing the excess amount of phosphate compounds is sent back to the neutralization step (step ii.)

Claims

CLAIMS1. A process for purifying a material feed comprising at least one of nickel and cobalt, at least one of uranium and scandium, and at least one of iron and aluminium, said process comprising the steps of:i. leaching said material feed in an aqueous acidic medium, thereby obtaining an aqueous leachate;ii. precipitating iron, aluminium, uranium and scandium, if present, in said aqueous leachate by adding a phosphate compound;iii. separating the precipitate formed in step ii. from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium, and uranium and / or scandium, respectively;characterized in that said process further comprises the steps of:al) subjecting said solid obtained in step iii. to acidification in an aqueous medium to dissolve nickel and / or cobalt compounds;a2) precipitating iron, aluminium, uranium and scandium, if present, in the acidified aqueous solution obtained in step al) by adding a phosphate compound; anda3) separating the precipitate formed in step a2) from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium and uranium and / or scandium, respectively;and / orbl) dividing the aqueous leachate of step i. in a first fraction and a second fraction, whereby said first fraction is processed in step ii.; b2) precipitating iron, aluminium, uranium and scandium, if present, in said second fraction obtained in step bl) by adding a phosphate compound; andb3) separating the precipitate formed in step b2) from the aqueous phase, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium and scandium and / or uranium.

2. Process according to claim 1, whereby step ii. comprises the steps of:ii. a. increasing the pH of the aqueous leachate obtained in step i., thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;ii. b. adding a phosphate compound to the basified leachate solution obtained in step ii. a., thereby obtaining an uranium and / or scandium precipitate.

3. Process according to claim 1 or 2, whereby step a2) comprises the steps of:a2) a. increasing the pH of the aqueous medium obtained in step al), thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;a2) b. adding a phosphate compound to the basified leachate solution obtained in step a2) a., thereby obtaining an uranium and / or scandium precipitate.

4. Process according to any of claims 1 to 3, whereby step b2) comprises the steps of:b2) a. increasing the pH of the aqueous leachate obtained in step bl)., thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;b2) b. adding a phosphate compound to the basified leachate solution obtained in step b2) a., thereby obtaining an uranium and / or scandium precipitate.

5. Process according to any of claims 1 or 4, wherein said phosphate compound is selected from the group consisting of H3PO4 and compounds comprising H2PO4’, HPO42’ or PO43’.

6. Process according to any of claims 1 to 5, wherein the pH of said aqueous leachate solution is increased in step ii. to between 2.5 and 6.0.

7. Process according to any of claims 1 to 6, wherein said pH in step ii. is increased by adding a Na base, Ca base, Ni base and / or Co base.

8. Process according to any of claims 1 to 7, whereby said aqueous leachate solution in step i. comprises a mineral acid selected from the group consisting of H2SO4, HCI and HNO3.

9. Process according to any of claims 2 to 8, whereby the precipitated iron and / or aluminium compounds in step ii. a. are not separated from the basified leachate solution prior to adding said phosphate compound in step ii. b.

10. Process according to any of claims 1 to 9, whereby said aqueous solution comprising nickel and / or cobalt obtained in step iii. is subjected to solvent extraction.

11. Process according to claim 10, whereby said solvent extraction makes use of an alkylphosphorus-based extractant, preferably an alkylphosphoric acid and / or derivatives thereof.

12. Process according to any of claims 1 to 11, whereby said aqueous solution comprising nickel and / or cobalt obtained in step a3) or b3) is recirculated upstream in the process.

13. Process according to any of claims 1 to 12, whereby said material feed comprises mixed hydroxide precipitate or cobalt hydroxide intermediate precipitate14. Process according to any of claims 1 to 13, said process comprising the steps of:i. leaching said material feed in an aqueous acidic medium, thereby obtaining an aqueous leachate;ii. a) increasing the pH of the aqueous leachate obtained in step i., thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;ii. b) adding a phosphate compound to the basified leachate solution obtained in step ii. a, thereby obtaining an uranium and / or scandium precipitate;Hi. separating the precipitate formed in step ii. from the basified leachate solution, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid;andal) Leaching at least part of said solid obtained in step Hi. in an aqueous acidic medium;a2) a. Increasing the pH of the aqueous leachate obtained in step al., thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;a2) b. Adding a phosphate compound to the basified leachate solution obtained in step a2)a., thereby obtaining an uranium and / or scandium precipitate;a3) Separating the precipitate formed in step a2) b. from the basified leachate solution, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium and scandium and / or uranium.

15. Process according to any of claims 1 to 14, said process comprising the steps of:i. leaching of said material feed in an aqueous acidic medium, thereby obtaining an aqueous leachate;ii. a) increasing the pH of the aqueous leachate obtained in step i., thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;ii. b) adding a phosphate compound to the basified leachate solution obtained in step ii. a), thereby obtaining an uranium and / or scandium precipitate;Hi. separating the precipitate formed in step ii. from the basified leachate solution, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid;andbl) Leaching of said solid obtained in step Hi. in the aqueous acidic medium of step L, and dividing the aqueous leachate of step i. in a first fraction and a second fraction, whereby said first fraction is processed in step ii.;b2) a. increasing the pH of the second fraction of aqueous leachate obtained in step bl. thereby precipitating iron and / or aluminium compounds and obtaining a basified leachate solution;b2) b. adding a phosphate compound to the basified leachate solution obtained in b2) a., thereby obtaining an uranium and / or scandium precipitate;b3) separating the precipitate formed in step b2) b. from the basified leachate solution, thereby obtaining an aqueous solution comprising nickel and / or cobalt and a solid comprising iron and / or aluminium and scandium and / or uranium.

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