Environmentally benign process for removing uranium and / or scandium from nickel and / or cobalt containing resources

Abstract

The present invention relates to an environmentally friendly process for removing uranium and / or scandium from nickel and / or cobalt containing resources, comprising the following steps: i. leaching a solid material feed comprising uranium and / or scandium, and at least 20 wt% of at least one of nickel and cobalt in an aqueous medium with a mineral acid, thereby obtaining a leach liquor solution comprising uranium and / or scandium ions, and at least one of nickel ions and cobalt ions, ii. at least partially precipitating uranium and / or scandium by adding a phosphate compound and bringing the pH of the leach liquor solution to at least 2.5, and separating the precipitate from the aqueous medium; iii. extracting the remaining uranium and / or scandium from the aqueous filtrate obtained in step ii. into an organic phase comprising an extractant and a diluent, thereby obtaining an aqueous raffinate comprising at least one of nickel ions and cobalt ions.

Description

Technical Field

[0001] This invention relates to the processing of nickel- and / or cobalt-containing resources to obtain an aqueous salt solution containing nickel and / or cobalt and having a reduced uranium and / or scandium content, which can be used in various industries such as stainless steel production, electroplating, and batteries. Background Technology

[0002] Uranium is a naturally occurring element, typically found in low concentrations in many types of rocks, and is commonly present in feedstocks used in the production of various metals. For example, nickel and cobalt are often extracted from ores that also contain uranium. However, because uranium is a radioactive element, it is crucial to isolate it during the processing of nickel-containing feedstocks to prevent potential harm to human health and the environment. Therefore, developing efficient methods for removing or reducing the amount of uranium in nickel-containing feedstocks is a key area of ​​research and development.

[0003] In addition, scandium is commonly found in ores used for nickel and cobalt extraction and is an undesirable impurity in aqueous solutions of nickel and / or cobalt products.

[0004] Currently, several methods exist for removing uranium from feedstocks, including uranium precipitation, solvent extraction, ion exchange, and microbiological methods. These methods can be effective, but they can also be expensive and complex, especially in cases of solvent extraction and ion exchange, which require specialized equipment and reagents. Furthermore, the disposal of the resulting waste streams from these methods can pose environmental challenges.

[0005] Methods for removing uranium from nickel-containing feedstocks using ion exchange resins have been developed by Kiegiel, K. et al., Kiegiel, K., Abramowska, A., B ... uszka, P., Zakrzewska-Ko tuniewicz, G., & Wo Kowicz, S. Solvent extraction of uranium from leach solutions obtained in processing of Polish low-grade ores. Journal of Radioanalytical and Nuclear Chemistry, 311, 589-598, 2017, https: / / doi.org / 10.1007 / s10967-016-5029-5. This method provides a simple alternative to methods such as solvent extraction, ion exchange, and microbial methods. However, the effectiveness of the proposed method may depend on the specific properties of the feedstocks and ion exchange resins used, and the scalability of the method for industrial applications may require further research and development.

[0006] WO2010118455 discloses a method for treating mixed hydroxide products (MHP) produced in metal extraction methods (e.g., nickel extraction methods). The method includes the steps of: treating the MHP with a first acidic solution at a pH in the range of 4 to 8 as a first redissolution step, and separating a first liquid formed in the first redissolution step from a first residue formed in that step. The method further includes the step of treating the first residue with a second acidic solution at a pH in the range of 0.5 to 4 as a second redissolution step. In this manner, impurities in the MHP can be selectively removed in both redissolution steps. A first solvent extraction step is used for the quantitative removal of zinc, uranium, and some calcium and manganese.

[0007] GB759900A describes a method for selectively precipitating uranium from a solution containing other metals by adjusting the pH in the presence of soluble phosphates or arsenates. According to one embodiment, a solution containing sulfates of U, Fe, Al, Zn, and Co with an Al / U ratio of 1:1 is treated with calcium hydroxide to a pH of 3.1, thereby precipitating basic ferric sulfate and lowering the pH to 2.8. Phosphoric acid is added and the pH is adjusted to 2.5 with calcium hydroxide, thus precipitating uranium.

[0008] WO2022090628A1 discloses a system for removing uranium from cobalt-rich raffinate. The system includes: a copper precipitation circuit for processing the cobalt-rich raffinate into a copper precipitate and arranged to receive phosphoric acid from a phosphoric acid reservoir to precipitate uranium contained in the cobalt-rich raffinate; a copper thickener circuit for processing the copper precipitate into a first stream containing copper hydroxide and precipitated uranium, and a second stream containing a cobalt sulfate solution and residual phosphoric acid; a measuring device for measuring an amount representing the amount of residual phosphoric acid in the second stream; and a control system for adjusting the dosage of phosphoric acid introduced into the copper precipitation circuit based on the measured amount and taking into account a target amount of residual phosphoric acid.

[0009] Methods relying on the precipitation of uranium and / or scandium with phosphate require a high excess of phosphate compounds to remove uranium and / or scandium from the solution to low ppm levels, and thus suffer the loss of valuable nickel and / or cobalt atoms via the uranium and / or scandium precipitate. Furthermore, such methods heavily depend on monitoring and control systems to ensure the correct dosage of phosphate. Therefore, there is a need for more efficient, effective, and sustainable methods for removing uranium and / or scandium from feedstocks. Such methods should be cost-effective, environmentally friendly, and generate minimal waste streams. Moreover, the methods should be applicable to a wide range of feedstocks and suitable for various industries. Summary of the Invention

[0010] The present invention provides a solution to at least one of the above-mentioned problems by providing a method for efficiently removing uranium and / or scandium from nickel- and / or cobalt-containing resources to produce a nickel and / or cobalt salt solution as described in claim 1.

[0011] Many of the obtained solid material feeds containing nickel and / or cobalt contain small amounts of uranium and / or scandium. This invention is advantageous because it provides a simple and efficient method for preparing aqueous solutions containing nickel and / or cobalt with significantly reduced uranium and / or scandium content. The method involves a series of steps, including leaching the solid material feed containing nickel and / or cobalt and uranium and / or scandium in an aqueous medium with a mineral acid, increasing the pH of the leachate solution to precipitate iron and aluminum (if present), and adding a phosphate compound to form a uranium and / or scandium precipitate. Finally, the method includes a solvent extraction step to remove remaining trace amounts of uranium and / or scandium.

[0012] The method can be applied to various solid material feeds, including MHP and CHIP. Furthermore, the present invention (comprising two uranium and / or scandium removal steps) for removing uranium and / or scandium from nickel- and / or cobalt-based feedstocks offers advantages in several respects over alternative methods that rely solely on solvent extraction, ion exchange, or precipitation with phosphate compounds. First, the proposed method is relatively simple and straightforward, involving only a few steps to remove most of the uranium and / or scandium: mineral acid leaching, pH increase, and the addition of a stoichiometric excess of phosphate compound to precipitate uranium and / or scandium. This simplicity reduces the complexity and cost associated with alternative methods, such as solvent extraction and ion exchange, which require specialized equipment and more complex chemical processes. Second, the proposed method is based on readily available materials, such as mineral acids and phosphate compounds, making it a cost-effective solution.

[0013] In contrast, current methods for uranium and / or scandium removal that rely solely on solvent extraction or ion exchange not only typically require expensive organic solvents and resins (contributing to their higher cost), but also generate complex organic solutions or resins that require further processing to recover valuable metals and dispose of uranium and / or scandium, increasing the complexity and cost of these methods. The method according to the invention has the advantage that uranium and / or scandium exits the process only via a 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. On the other hand, trace amounts of uranium and / or scandium are further purified and removed from the solution via solvent extraction, which is carried out in a manner that retains the solvent while also removing other impurities. Overall, with the present invention, reagent costs are reduced and the recovery rate of nickel and / or cobalt is improved. Attached Figure Description

[0014] As further guidance, accompanying drawings are included to better understand the teachings of the invention. These drawings are intended to aid in the description of the invention and are in no way intended to limit the invention currently disclosed.

[0015] The accompanying drawings and the symbols contained therein have the meanings commonly understood by those skilled in the art to which this invention pertains.

[0016] Figure 1 A preferred arrangement of the steps of the method for feeding solid materials containing uranium according to the present invention is shown.

[0017] Figure 2 A preferred arrangement of the method steps according to the invention for feeding a solid material containing both uranium and scandium is shown.

[0018] Figure 3 A preferred arrangement of the steps of the method for feeding a solid material containing scandium according to the present invention is shown. Detailed Implementation

[0019] Unless otherwise defined, all terms used in this disclosure (including technical and scientific terms) shall have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains. As further guidance, terminology definitions are included to better understand the teachings of this invention.

[0020] The following terms used in this article have the following meanings:

[0021] Unless the context clearly specifies otherwise, as used herein, “a / an” and “the” refer to the singular and plural objects, respectively. For example, “a compartment” means one or more compartments.

[0022] The term "about" as used herein with respect to measurable values ​​(e.g., parameters, quantities, durations, etc.) is intended to cover deviations from the specified value 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 (to the extent that such deviations are appropriate in the disclosed invention). However, it should be understood that the value referred to by the modifier "about" is itself specifically disclosed.

[0023] As used herein, “comprise, comprising, and comprisedof” is synonymous with “include, including, and includes” or “contain, containing, and contains” and is an inclusive or open-ended term used to specify the presence of subsequent content (e.g., components) without excluding or precluding the presence of additional undocumented components, features, elements, parts, or steps known in the art or disclosed herein.

[0024] The term “at least one of nickel and cobalt” as used herein should be understood to be synonymous with the term “at least one selected from the group consisting of nickel and cobalt” and should be understood to mean “nickel, cobalt, or both nickel and cobalt”.

[0025] The term “at least one of iron and aluminum” as used herein should be understood as synonymous with the term “at least one of the group consisting of iron and aluminum”, and should be understood as meaning “iron, aluminum, or both iron and aluminum”.

[0026] The term "respectively" is used herein in conjunction with the expression "and / or". Thus, those skilled in the art will understand how to interpret the meaning of "and / or" in a specific context. As those skilled in the art will understand from the context of the description, in the context of this invention, the term "respectively" refers to the correspondence between the presence of a specific element in the solid material feed and the resulting ions in the solution. That is, it means that if the solid material feed contains uranium, the solution will contain uranium ions; if the solid material feed contains scandium, the solution will contain scandium ions; and if the solid material feed contains both uranium and scandium, the solution will contain both uranium ions and scandium ions; or if the solid material feed contains nickel, the solution will contain nickel ions; if the solid material feed contains cobalt, the solution will contain cobalt ions; and if the solid material feed contains both nickel and cobalt, the solution will contain both nickel ions and cobalt ions.

[0027] The range of values ​​recorded by the endpoints includes all numbers and fractions falling within the range, as well as the recorded endpoints. Unless otherwise defined, or unless it is obvious to those skilled in the art from the use of percentages and the different meanings in the context of their use, all percentages shall be understood as weight percentages (abbreviated as “weight%”) or volume percentages (abbreviated as “volume%”).

[0028] In the context of this invention, the term "raw material feed" is considered synonymous with the terms "solid material feed," "solid material raw material," or "raw material," and refers to one or more raw materials comprising at least one of uranium and scandium, one of nickel and cobalt, and optionally manganese and / or lithium. The metal may be included on its own, or may be included as a compound of the aforementioned metals or as a mixture of compounds. In some embodiments, the raw material feed may comprise any one or a combination of raw materials and recycled materials. Examples of raw materials include, but are not limited to, mixed hydroxide precipitate (MHP), nickel sulfide concentrate, cobalt sulfide concentrate, nickel laterite, nickel matte, or nickel iron. Examples of recycled materials include, but are not limited to, waste cathode materials, and materials derived from recycled lithium-ion batteries or lithium-ion battery manufacturing waste, collectively referred to herein as "black matter."

[0029] In the context of this invention, the term "MHP" is considered an abbreviation for the term "Mixed Hydroxide Precipitate." Mixed Hydroxide Precipitate (MHP) is an intermediate product of nickel metallurgy, typically derived from the processing of laterite ores containing primarily nickel and minor amounts of cobalt. It can also be produced from other sources, such as as a byproduct of Ni recovery from various metallurgical or mining operations. Alternatively, or additionally, MHP can be obtained from nickel- and / or cobalt-containing hydroxide materials generated as production waste during the preparation of cathode materials, or from battery recycling methods.

[0030] In the context of this invention, the term "CHIP" is considered an abbreviation for the term "cobalt hydroxide intermediate precipitate." Cobalt hydroxide intermediates primarily comprise cobalt and typically have a cobalt content of 25% to 40% by weight relative to the total dry weight of the intermediate product. Typically, the CHIP contains a significant amount of nickel. CHIPs are known to have very low impurity levels, making them attractive for the methods according to the invention.

[0031] The term "solid material feed" can refer to a solid feed comprising MHP products, CHIP products, or mixtures of two or more MHP products, mixtures of two or more CHIP products, or mixtures of one or more MHP products and one or more CHIP products. Preferably, the raw material feed comprises at least one nickel compound and at least one cobalt compound. Preferably, the nickel compound and the cobalt compound are contained as nickel(II) compounds and as cobalt(II) compounds, respectively. However, the nickel compound and the cobalt compound may also be contained in higher oxidation states (e.g., 3+ or 4+), or the metal-containing feed may comprise a mixture of nickel and / or cobalt compounds in oxidation states 2+ and 3+ and / or 4+. Furthermore, the raw material feed may comprise an alloy of nickel(O) and cobalt(O), and / or the raw material feed may comprise one or more ores containing nickel and cobalt.

[0032] The solid material feed may also contain uranium and / or scandium, and may contain iron and / or aluminum, as well as one or more impurities, wherein the impurities contain one or more selected from the list including Cu, Zn, Mn, Li, F, C, Ca, Si, P, As, Cd, Sb and Mg.

[0033] In the context of this invention, the term "phosphate compound" refers to a compound containing phosphate ions (PO4). 3- Phosphate is a chemical compound of phosphoric acid or its derivatives. The phosphate ion is an anion having a central phosphorus atom bonded to four oxygen atoms. The group consisting of phosphate compounds includes phosphoric acid (H3PO4) and compounds containing H2PO4. - HPO4 2- and / or PO4 3- Inorganic salts. Examples of phosphate compounds are (but are not limited to): phosphoric acid (H3PO4), sodium phosphate (Na3PO4), calcium phosphate (Ca3(PO4)2), and superphosphate (Ca(H2PO4)2). H2O).

[0034] In the context of this invention, the term "continuous method" should be considered as a method in which the resulting solution has a substantially constant outflow rate and composition. Specifically, a continuous method is a method in which the resulting solution has a constant composition within a range considered normal to be normal method deviations. More specifically, the resulting solution has a composition in which the concentration of each component is within a range of + / - 20% or less, preferably + / - 10% or less, more preferably + / - 5% or less, and even more preferably + / - 3% or less of its average concentration. In a preferred embodiment, the invention provides a continuous method operating under steady-state conditions.

[0035] In the context of this invention, the term "aqueous medium" is used for water-based solutions. Aqueous media facilitate the handling of reactor contents, such as mixing or pumping. The aqueous medium may already contain some other components involved in the reaction, or those components may be added later. The aqueous medium may, in particular, contain mineral acids.

[0036] In the context of this invention, the following terms are used to identify "organic phase", its components or as a whole:

[0037] i. In the context of this invention, the term “organic phase” should be understood to be synonymous with the term “solvent” or “solvent mixture”, and specifies a liquid composition comprising one or more extractants, diluents, and optionally one or more modifiers.

[0038] ii. An “extractant” or extractant is an active component in an organic phase that extracts a metal species into the organic phase by chemically binding with the metal species and forming a metal-extractant complex, the complex being more soluble in the organic phase than in the aqueous phase.

[0039] iii. A “diluent” is an organic molecule, or typically a mixture of different organic molecules, added to the organic phase to dilute the extractant and allow for the dissolution of the metal complex, improve the physical properties of the organic phase (especially phase separation), and reduce its cost, as diluents are generally cheaper than extractants. Diluents are typically kerosene fractions and can be aliphatic or aromatic hydrocarbons, cycloalkanes, etc., or mixtures thereof. Preferred diluents are kerosene-based petroleum fractions, such as Escaid, Elixore, Shellsol, Isopar, etc.

[0040] iv. The organic phase may also contain "modifiers". Modifiers are sometimes added to improve the solubility of metal complexes in the organic phase, to alter the physical properties of the solvent and thus prevent the formation of interfacial impurities or a third phase, as these phenomena are undesirable in solvent extraction. Modifiers may also be added to prevent the chemical decomposition of the extractant or diluent. However, modifiers may impair the selectivity of the organic phase because they may participate in the formation of metal-extractant complexes.

[0041] The "selectivity" S of an extractant for one metal over another can be expressed as the ratio of the partition coefficients D of the two metals:

[0042] S U / Ni =D U / D Ni

[0043] The "partition factor" of a metal should be understood as the ratio of the corresponding equilibrium concentration of that metal in the organic phase to that of the same metal in the aqueous phase:

[0044] D M =[M] O / [M] A

[0045] Where M is a metal, such as nickel, uranium, or scandium, O refers to the organic phase, and A refers to the aqueous phase.

[0046] The term “O / A ratio” or “O / A” refers to the volume ratio of the organic phase (O) to the aqueous phase (A) used for solvent extraction or solvent back-extraction.

[0047] The overall inventive concept of this invention comprises a method for preparing a salt solution of nickel and / or cobalt, the method comprising the following steps:

[0048] i. Leaching a solid material feed in an aqueous medium with a mineral acid, the solid material feed comprising uranium and / or scandium, and at least 20% by weight of nickel and cobalt relative to the total dry weight of the solid material feed, thereby obtaining a leachate solution comprising uranium and / or scandium ions, and at least one of nickel ions and cobalt ions, respectively.

[0049] ii. By adding a phosphate compound and adjusting the pH of the leachate solution to at least 2.5, uranium and / or scandium are at least partially precipitated, and the precipitates are separated from the aqueous medium;

[0050] iii. Extract the remaining uranium and / or scandium in the aqueous filtrate obtained in step ii. into an organic phase containing an extractant and a diluent, thereby obtaining an aqueous raffinate containing at least one of nickel ions and cobalt ions.

[0051] In the context of this invention, those skilled in the art will understand that when leaching a solid material feed containing uranium but not scandium, a uranium-containing leachate solution is obtained in step i, uranium is precipitated in step ii, and uranium is extracted in step iii. Similarly, when leaching a solid material feed containing scandium but not uranium, a scandium-containing leachate solution is obtained in step i, scandium is precipitated in step ii, and scandium is extracted in step iii.

[0052] When leaching a solid material feed containing both uranium and scandium, a leachate solution containing uranium and scandium is obtained in step i, uranium and scandium are precipitated in step ii, and uranium and scandium are extracted in step iii.

[0053] The solid feed material may contain at least 1 ppm of uranium based on the dry weight of the solid feed material. The solid feed material may contain at least 1 ppm of scandium based on the dry weight of the solid feed material.

[0054] The method of the present invention can be used in various industries, such as stainless steel production, electroplating, and batteries. The method of the present invention (comprising two stages of uranium and / or scandium removal, more specifically phosphate precipitation and solvent extraction) is advantageous over alternative methods that utilize only solvent extraction, ion exchange, or precipitation with phosphate compounds or other compounds (e.g., ammonium carbonate or ammonium hydroxide). That is, 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 valuable metals and uranium for disposal, increasing the complexity and cost of these methods. On the other hand, removing trace amounts of uranium and / or scandium via precipitation with phosphate compounds requires the use of highly excessive phosphate compounds, which ultimately results in the precipitation of valuable cobalt and / or nickel atoms from the leaching solution. The method according to the invention has the advantage that uranium and / or scandium exit the process only via a uranium and / or scandium precipitate that can be easily filtered and separated from the leaching solution, allowing for the efficient recovery and further processing of uranium and / or scandium respectively. Furthermore, uranium and / or scandium precipitation can be performed efficiently, limiting the required excess of phosphate compounds, as trace amounts of uranium and / or scandium are further purified and removed from the solution via solvent extraction. Preferably, the method according to the invention is carried out in a manner that retains the solvent while also removing other impurities. This is achieved by back-extracting uranium and / or scandium from the solvent with a high concentration of acid, wherein the eluent containing uranium and / or scandium can be recycled to the first step of the method. Overall, the invention provides a unique and efficient method that minimizes the use of hazardous chemicals, maximizes the recovery of uranium, scandium, nickel, and cobalt, and produces nickel- and / or cobalt-rich solutions with low uranium and scandium content.

[0055] In a first aspect, the present invention provides a method for preparing a salt solution of nickel and / or cobalt, the method comprising the steps of:

[0056] i. Leaching a solid material feed in an aqueous medium with a mineral acid selected from the group consisting of H2SO4, HCl and HNO3, the solid material feed comprising uranium and / or scandium, at least 20% by weight of nickel and at least 0.05% by weight of cobalt relative to the total dry weight of the solid material feed, thereby obtaining a leachate solution comprising uranium and / or scandium ions and at least one of nickel ions and cobalt ions, respectively.

[0057] ii. The pH of the leachate solution is increased to at least 2.5 by adding alkali, thereby precipitating iron and / or aluminum compounds and obtaining an alkali-treated leachate solution;

[0058] iii. Simultaneously with or after step ii., add a phosphate compound to the alkalized leachate solution from step ii. to form uranium and / or scandium precipitates, respectively;

[0059] iv. Separate the precipitate formed in step iii. from the leachate solution to obtain an aqueous solution containing uranium and / or scandium, and containing at least one of nickel ions and cobalt ions; and

[0060] v. From the aqueous solution obtained in step iv., uranium and / or scandium are extracted into an organic phase containing an extractant and a diluent, respectively, thereby obtaining an organic phase enriched with uranium and / or scandium and an aqueous raffinate containing at least one of nickel ions and cobalt ions, respectively.

[0061] The method involves leaching a solid material feed containing at least one of uranium and / or scandium, nickel and cobalt, and at least one of iron and aluminum in an aqueous medium with a mineral acid selected from the group consisting of H2SO4, HCl, and HNO3, thereby obtaining a leachate solution containing uranium and / or scandium ions and nickel and / or cobalt ions, respectively. This leaching step is performed to dissolve uranium, scandium, nickel, cobalt, iron, and aluminum (if present) in the solid material feed into the solution. The leachate solution is then subjected to a series of steps to remove, or at least reduce, the amount of uranium and scandium (if present in the leachate solution) by forming uranium and / or scandium precipitates and performing solvent extraction of uranium and / or scandium, respectively.

[0062] Figure 1 A preferred embodiment of the present invention for feeding a solid material containing uranium is described, wherein a uranium-containing leachate solution is obtained in step i, a uranium precipitate is obtained in step iii, an aqueous solution containing uranium is obtained in step iv, and an organic phase enriched with uranium is obtained in step v.

[0063] Figure 2 A preferred embodiment of the present invention for a solid material feed containing both uranium and scandium is shown, wherein a leachate solution containing uranium and scandium is obtained in step i., a uranium and scandium precipitate is obtained in step iii., an aqueous solution containing uranium and scandium is obtained in step iv., and an organic phase enriched with uranium and scandium is obtained in step v.

[0064] Figure 3 A preferred embodiment of the present invention for a solid material feed containing scandium but not uranium is shown, wherein a scandium-containing leachate solution is obtained in step i, a scandium-containing precipitate is obtained in step iii, an aqueous solution containing scandium is obtained in step iv, and an organic phase enriched with scandium is obtained in step v.

[0065] In step i., a solid material feed is leached in an aqueous medium in a mineral acid selected from H2SO4, HCl, and HNO3, or mixtures thereof, comprising at least one of uranium and / or scandium, nickel and cobalt, and at least one of iron and aluminum. Preferably, the mineral acid is H2SO4 or HCl, and more preferably, the mineral acid is H2SO4 because it allows for the direct formation of nickel sulfate and cobalt sulfate, respectively, and because sulfuric acid is easier to handle. Optionally, step i. can be performed in a medium selected from H3PO4 and containing H2PO4. - HPO4 2- and PO4 3- The process is carried out in the presence of phosphate compounds that form the group of compounds.

[0066] The raw materials used in the method may be any raw materials containing at least one of uranium and / or scandium, nickel and cobalt, and at least one of iron and aluminum. The solid material feed material may contain 1 to 1000 ppm of uranium, or 1 to 100 ppm of uranium, or 5 to 100 ppm of uranium, or 10 to 70 ppm of uranium relative to the total dry weight of the solid material feed.

[0067] The solid material feed may contain 1 to 5000 ppm scandium, or 1 to 1000 ppm scandium, or 5 to 750 ppm scandium, or 10 to 550 ppm scandium relative to the total dry weight of the solid material feed.

[0068] The solid material feed typically contains at least 20% by weight, more preferably at least 25% by weight, even more preferably at least 30% by weight, and less than 60% by weight, more preferably less than 53% by weight of nickel and cobalt relative to the total dry weight of the solid material feed.

[0069] The solid material feed typically contains at least 0.05% by weight, more specifically at least 0.09% by weight, or even more specifically at least 0.2% by weight, and less than 10% by weight of either iron or aluminum relative to the total dry weight of the solid material feed.

[0070] The solid material feed may contain one or more other impurities, said impurities comprising one or more selected from the list including Cu, Zn, Mn, Li, F, C, Ca, Si, P, As, Cd, Sb and Mg.

[0071] The preferred raw materials are mixed hydroxide precipitate (MHP) and cobalt hydroxide precipitate (CHIP).

[0072] In a preferred embodiment, the mixed hydroxide precipitate (MHP) contains 5 to 100 ppm of U relative to the total dry weight of the mixed hydroxide precipitate.

[0073] In a preferred embodiment, the mixed hydroxide precipitate (MHP) contains 5 to 550 ppm of Sc relative to the total dry weight of the mixed hydroxide precipitate.

[0074] In a preferred embodiment, the mixed hydroxide precipitate (MHP) contains 5 to 100 ppm of U and 10 to 550 ppm of scandium relative to the total dry weight of the mixed hydroxide precipitate.

[0075] Preferably, the mixed hydroxide precipitate contains nickel in an amount of 25 to 60% by weight, preferably 33 to 53% by weight, relative to the total dry weight of the mixed hydroxide precipitate. Preferably, the mixed hydroxide precipitate contains cobalt in an amount of at least 0.1% by weight, preferably at least 0.2% by weight, and more preferably at least 0.9 to 6.0% by weight, relative to the total dry weight of the mixed hydroxide precipitate. Preferably, the mixed hydroxide precipitate contains manganese in an amount of at least 0.001% by weight, preferably at least 0.01% by weight, and more preferably at least 0.1 to 7.0% by weight, relative to the total dry weight of the mixed hydroxide precipitate. Preferably, the mixed hydroxide precipitate contains carbon in an amount of 0.01 to 5.00% by weight, more preferably 0.01 to 3.00% by weight, and even more preferably 0.01 to 1.00% by weight, relative to the total dry weight of the mixed hydroxide precipitate. Preferably, the mixed hydroxide precipitate contains zinc in an amount of 0.01 to 0.30% by weight, relative to the total dry weight of the mixed hydroxide precipitate. Preferably, the mixed hydroxide precipitate contains iron in an amount of 0.1 to 3.0% by weight, relative to the total dry weight of the mixed hydroxide precipitate. Preferably, the mixed hydroxide precipitate contains Al in an amount of 0.1 to 3.0% by weight, relative to the total dry weight of the mixed hydroxide precipitate. Preferably, the mixed hydroxide precipitate contains water in an amount of 25 to 60% by weight, preferably 30 to 55% by weight, relative to the total wet weight of the mixed hydroxide precipitate.

[0076] The leaching method can be carried out at temperatures ranging from ambient to 100°C, preferably from 70 to 95°C, and at pressures ranging from atmospheric to 10 bar, preferably from atmospheric to 5 bar. The leaching method can also be carried out in the presence of a reducing agent to increase the leaching yield. The reducing agent can be selected from various reducing agents, such as sulfur dioxide, hydrogen peroxide, hydrazine, and hydroxylamine.

[0077] In step ii., by adding an alkali to the solution, the pH of the leachate solution obtained in step i. is increased to at least 2.5, and more preferably to 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 between therebetween, thereby precipitating iron and / or aluminum. The alkali used can be any suitable inorganic or organic alkali, preferably an inorganic alkali 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 above substances. More preferably, the alkali is NaOH, KOH, Ca(OH)2 or NiCO3, or a combination thereof. Preferred alkalis are Ca(OH)2 and NiCO3. Precipitates containing iron and / or aluminum may optionally be filtered out from the leachate solution.

[0078] In a preferred embodiment, the leachate solution obtained in step i. is processed in a multi-step sequence, wherein in step ii.(a), the pH of the leachate solution is first increased to a pH between 2.5 and 4.5, preferably between 3.0 and 4.5, more preferably between 3.5 and 4.5, and most preferably to a pH of about 4. The increase in pH causes selective precipitation of iron and aluminum compounds, while nickel and cobalt ions remain in the solution. Subsequently, in step ii.(b), the pH of the alkalized leachate solution from step ii.(a) is increased to a pH between 4.5 and 7.0, preferably between 4.5 and 6.0, more preferably between 4.5 and 5.5, and most preferably to a pH of about 5. Preferably, the precipitate formed in step ii.(a) is filtered out prior to step ii.(b).

[0079] The precipitate containing iron and / or aluminum formed in step ii. can be partially or completely filtered out from the alkalized leachate solution before the addition of the phosphate compound in step iii. At least partial removal of the precipitate provides the advantage that the final precipitate filtered out in step iv. has a higher content of uranium and / or scandium, which improves the efficiency of subsequent uranium and / or scandium recovery. However, in a preferred embodiment, the precipitate containing iron and / or aluminum formed in step ii. is not filtered out from the alkalized leachate solution before the addition of the phosphate compound in step iii. Preferably, the phosphate compound is added to the leachate solution of step i. and / or to the alkalized leachate solution of steps ii.(a) and / or ii.(b), the solution containing the precipitate of iron and / or aluminum.

[0080] During precipitation in step ii., uranium (if present) will remain primarily in the leaching solution. However, depending on the conditions applied in step ii. (e.g., pH), a significant amount of scandium ions (if present) may precipitate before the addition of the phosphate compound in step iii. Typically, according to the invention, the amount of scandium ions (if present) precipitated in the leaching solution in step ii. is between 5% and 60% of the scandium atoms present in the leaching solution. While it is possible to precipitate scandium to an even greater extent by altering the pH, this is not preferred as it may result in the loss of valuable elements (e.g., nickel or cobalt) in the precipitate. This problem is avoided in the invention by adding a phosphate compound in step iii.

[0081] In step iii, a phosphate compound is added to the leachate solution obtained in step i and / or to the alkalized leachate solution obtained in step ii to form uranium and / or scandium precipitates. The phosphate compound used may be selected from H3PO4, H2PO4, etc. - HPO4 2- and PO4 3- The group consists of phosphate compounds added at a stoichiometric excess of 10 to 1000 times, preferably 25 to 500 times, preferably 50 to 300 times, and most preferably about 100, 150, or 200 times the amount of uranium ions in the leachate solution obtained in step i. and / or the alkalized leachate solution obtained in step ii.

[0082] The phosphate compound can be added in an excess of 5 to 1000 times, preferably 10 to 1000 times, more preferably 15 to 500 times, more preferably 15 to 500 times, and most preferably about 100, 150, or 200 times the total amount of uranium and scandium ions in the leachate solution obtained in step i.

[0083] The uranium and / or scandium precipitate is then filtered out of the leaching solution in step iv. If the precipitate containing iron and / or aluminum was not previously filtered out of the leaching solution before step iii, it can be filtered out together with the uranium and / or scandium precipitate in step iv. The method can be carried out in a single container, which simplifies the process and reduces costs. Preferably, the method is a continuous process.

[0084] The precipitate containing uranium and / or scandium can then be subjected to a reduction process to recover uranium and / or scandium. The reduction process may include roasting the precipitate in air, followed by acid leaching to recover uranium and / or scandium.

[0085] In a preferred embodiment of the invention, if uranium is present in the solid feed material, then 20 to 95 atomic% (at.%), preferably at least 30 atomic%, more preferably at least 55 atomic%, preferably less than 90 atomic%, and more preferably less than 85 atomic% of the uranium ions present in the alkalized leachate solution in step ii. precipitate into the uranium precipitate in step iii.

[0086] According to a first aspect, step v. includes extracting uranium and / or scandium from the aqueous solution obtained in step iv. into an organic phase containing an extractant and a diluent, thereby obtaining an organic phase enriched with uranium and / or scandium and an aqueous raffinate containing at least one of nickel ions and cobalt ions.

[0087] Generally, any extractant with high selectivity for uranium and / or scandium over nickel and / or cobalt can be used. For example, alkylphosphorus-based extractants such as tributyl phosphate or di(2-ethylhexyl)phosphoric acid (D2EHPA), or octylphenyl phosphate, carboxylic acid derivatives such as neodecanoic acid, tertiary or quaternary ammonium, such as Alamine 336, can be used. N,N -A mixture of dioctyl-1-octylamine or triC8-10 alkylamines) or Aliquat 336 ( N -methyl- N, N,N -trioctylammonium chloride), or mixtures thereof. The term "alkylphosphide-based extractant" is equivalent to "extractant containing an alkylphosphide group".

[0088] In a preferred embodiment, other impurities such as manganese, calcium, zinc, copper, and cadmium are also selectively extracted into the organic phase, along with uranium and / or scandium (if present), in preference to nickel and cobalt.

[0089] In one embodiment, in addition to uranium and / or scandium and other impurities (such as manganese, calcium, zinc, copper and cadmium), cobalt is also extracted into the organic phase to separate cobalt from nickel.

[0090] In step v., 1 to 80 atomic percent, preferably greater than 5 atomic percent, more preferably greater than 10 atomic percent, most preferably greater than 15 atomic percent, preferably less than 70 atomic percent, more preferably less than 45 atomic percent of uranium ions (if present) in the alkalized leachate solution of step ii. are extracted into the organic phase of step v.

[0091] In a preferred embodiment, the invention provides a method according to a first aspect of the invention, wherein the extraction in step v. is carried out at a temperature between 20 and 45°C, preferably between 20 and 40°C, and even more preferably between 25 and 35°C. It has been found that lower temperatures provide better selectivity for Mn extraction, and thus provide better separation of Mn from Co. Preferably, the temperature is above 20°C, or even above 25°C, to facilitate operating temperature settings under high ambient temperatures.

[0092] Solvent extraction step v. can be carried out in any suitable apparatus and is not particularly limited thereto. Solvent extraction equipment typically includes at least one or more devices consisting of a mixer-sedimentation unit, a column contactor, a centrifugal contactor, or any other type of contactor. Preferably, extraction is carried out in a countercurrent configuration.

[0093] In a preferred embodiment, the present invention provides a method according to a first aspect of the invention, wherein the aqueous uranium and / or scandium, nickel and / or cobalt solution entering step v. prior to contact with the solvent containing the extractant has a pH between 1.0 and 5.0, more preferably between 1.5 and 3.5, and most preferably between 2.0 and 3.0, which creates a chemical equilibrium between the aqueous nickel solution and the solvent.

[0094] In one embodiment, the present invention provides a method according to a first aspect of the invention, wherein the aqueous uranium and / or scandium, nickel and / or cobalt solution obtained in step iv. is acidified before proceeding to step v.

[0095] In a preferred embodiment, the present invention provides a method according to a first aspect of the invention, wherein the organic phase used in step v. comprises the extractant present in an amount of 5 to 50 vol% relative to the total volume of the organic phase, and the diluent present in an amount of 50 to 95 vol% relative to the total volume of the organic phase. More preferably, the organic phase comprises the extractant present in an amount of 30 to 40 vol% and the diluent present in an amount of 60 to 70 vol%. The organic phase may contain a modifier.

[0096] In a preferred embodiment, the present invention provides a method according to a first aspect of the invention, wherein the diluent is a hydrocarbon. More generally, any organic solvent that is immiscible with water and capable of dissolving the extractant can be used. Therefore, the diluent is not particularly limited. As examples of diluents, kerosene-based compounds can be used, which can be aliphatic, cycloalkane, aromatic, or even mixtures thereof.

[0097] In a preferred embodiment, the present invention provides a method according to a first aspect of the invention, wherein the extractant used in step v. comprises an alkylphosphide-based extractant. Due to the presence of coordinating oxygen atoms in these molecules, alkylphosphide-based acids act as chelating extractants. Among elements in an aqueous solution, elements that form corresponding chelate compounds with higher stability are more conducive to extraction efficiency than elements that are less likely to form chelate compounds. Alkylphosphide-based acids exhibit high selectivity for uranium and / or scandium, respectively, over nickel and cobalt. The alkylphosphide-based acid extractant may be selected from, but is not limited to, the following options:

[0098] - Phosphoric acids, such as di(2-ethylhexyl)phosphoric acid (also known as D2EHPA, DEHPA, HDEHP, P204), which have the formula (C8H... 17 Organophosphorus compounds such as O)2PO2H, or, for example, dodecyl ethers of phosphoric acid (DDFK).

[0099] - Phosphonic acids, such as 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (also known as EHEHPA, HEHEHP, P507, PC88A), which have the formula R1=(C8H 17 (C8H) 17 Organophosphorus compounds with O)PO2H,

[0100] - Phosphinolic acid, such as bis-(2,4,4-trimethylpentyl)phosphinolic acid (also known as Cyanex 272, Ionquest 290), which is a phosphinolic acid having the formula (C 16 H 34 Organophosphorus compounds containing PO2H.

[0101] - Phosphate esters, such as tributyl phosphate or octylphenyl phosphate.

[0102] - Phosphine oxides, such as trioctylphosphine oxide.

[0103] Among these alkylphosphide-based acid extractants, phosphates exhibit the highest selectivity for uranium and scandium. Such phosphates can be used in their protonated forms and also as derivatives, including alkali metal-converted forms, i.e., phosphates partially neutralized with alkali metal hydroxides, and / or forms preloaded with cobalt, nickel, or a mixture of nickel and cobalt. It has been found that preloading the extractant used in step v. with nickel and / or cobalt allows for optimal and improved extraction without sacrificing the extractant's processability. During the preloading step, the partially neutralized extractant (i.e., in its alkali metal-converted form) exchanges the alkali metal (typically sodium) on the extractant for nickel and / or cobalt from the aqueous nickel sulfate and / or cobalt sulfate solution. Preferably, the residual amount of alkali metal on the preloaded solvent is as low as possible to limit the transfer of residual alkali metal from the preloaded solvent to the aqueous mixed metal sulfate solution when extracting impurities from the solution.

[0104] Preferably, the alkylphosphine-based extractant comprises alkylphosphine and / or its derivatives. More preferably, the alkylphosphine-based extractant comprises alkylphosphine and / or its conjugate base. Most preferably, the alkylphosphine is di(2-ethylhexyl)phosphine, and / or its nickel or cobalt salt.

[0105] In one embodiment, the uranium- and / or scandium-enriched organic phase obtained in step v. is treated with a first back-extraction fluid (S1).

[0106] In one embodiment of the invention, all elements extracted to the organic phase in step v. except for uranium, scandium, and iron (if present) are recovered from the organic phase after step v. using a first back-extraction fluid (S1). This allows for the production of a first aqueous eluent (E1) typically containing manganese, calcium, zinc, copper, and cadmium (if present), while uranium and scandium (if present) remain in the organic phase. Through this step, the capacity of the extractant is largely regenerated, producing a solvent free of metals other than uranium and scandium, which can be reused for extraction.

[0107] In a second aspect of the invention, the uranium and / or scandium-enriched organic phase obtained in step v. is treated with a first back-extraction fluid (S1) and subsequently with a second back-extraction fluid (S2) to obtain a first aqueous eluent (E1) and a second aqueous eluent (E2), respectively.

[0108] The residual acid concentration of the backextraction fluid after the second backextraction step is higher than that after the first backextraction step, wherein the residual acid concentration is measured at the final contact stage between the organic phase and the corresponding backextraction fluid (i.e., the stage where the aqueous backextraction fluid leaves the backextraction section in a countercurrent configuration). The aqueous backextraction fluid after backextraction is also referred to as the eluent. Therefore, the acid concentration of the second eluent solution (E2) is higher than that of the first eluent solution (E1).

[0109] Following treatment with the first back-extraction fluid (S1), the organic phase is subsequently contacted with a second back-extraction fluid (S2), resulting in the selective elution of significant amounts of uranium and / or scandium from the organic phase. Only the second back-extraction step results in the removal of uranium and / or scandium from the organic phase, which exhibits high selectivity for uranium and scandium. This is due to the higher residual acid concentration at the final contact stage between the organic phase and the second back-extraction fluid, and in other words, to the higher acid concentration in the second eluent (E2).

[0110] Preferably, the first and second back-extraction fluids are one or more selected from the group consisting of hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, and perchloric acid. More preferably, the first and second mineral acids are selected from sulfuric acid, hydrochloric acid, and phosphoric acid.

[0111] Preferably, the first back-extraction fluid (S1) has an acid concentration of 0.5 M to 5 M. The term "acid concentration" as used herein refers to the initial acid concentration of the back-extraction fluid, i.e., it is measured at the initial contact stage between the organic phase and the back-extraction fluid.

[0112] In a preferred embodiment, the first back-extraction fluid contains a sulfuric acid concentration of at least 50 g / L, more preferably at least 100 g / L, more preferably less than 500 g / L, and more preferably less than 250 g / L.

[0113] In a preferred embodiment, the first back-extraction fluid (S1) contains a hydrochloric acid content of at least 18 g / L, more preferably at least 36 g / L, and more preferably less than 182 g / L, and more preferably less than 91 g / L.

[0114] In a preferred embodiment, the first back-extraction fluid contains a phosphoric acid concentration of at least 50 g / L, more preferably at least 100 g / L, more preferably less than 500 g / L, and more preferably less than 250 g / L.

[0115] Preferably, the second back-extraction fluid (S2) has an acid concentration of 2 M to 10 M. The upper limit of the concentration of the second back-extraction fluid is determined by the stability of the extractant under acidic conditions.

[0116] In a preferred embodiment, the second back-extraction fluid (S2) contains a sulfuric acid concentration of at least 200 g / L, more preferably at least 250 g / L, most preferably at least 500 g / L, and preferably less than 1000 g / L, more preferably less than 800 g / L.

[0117] In a preferred embodiment, the second back-extraction fluid (S2) contains a hydrochloric acid concentration of at least 75 g / L, more preferably at least 100 g / L, most preferably greater than 180 g / L, more preferably less than 350 g / L, and more preferably less than 250 g / L.

[0118] In a preferred embodiment, the second back-extraction fluid (S2) contains a phosphoric acid concentration of at least 200 g / L, more preferably at least 250 g / L, most preferably at least 500 g / L, and preferably less than 1000 g / L, more preferably less than 800 g / L.

[0119] In a preferred embodiment, the acid concentration of the second back-extraction fluid (S2) is higher than that of the first back-extraction fluid (S1).

[0120] The back-extraction step can be performed in any suitable apparatus and is not particularly limited thereto. Back-extraction equipment typically includes at least one or more devices consisting of a mixer-sedimentation unit, a column contactor, a centrifugal contactor, or any other type of contactor. Preferably, back-extraction of the first back-extraction fluid is performed in a countercurrent configuration.

[0121] In a preferred embodiment, back-extraction with a second back-extraction fluid is carried out in a single extraction step.

[0122] In a preferred embodiment, the present invention provides a method according to a first aspect of the invention, wherein the back-extraction of an organic phase with first and second back-extraction fluids is carried out at a temperature between 20 and 55°C, preferably between 20 and 45°C, more preferably between 25 and 40°C, and most preferably at a temperature of about 25°C, 30°C, 35°C or 40°C, or any value therebetween.

[0123] In a preferred embodiment, the invention provides a post-processing step according to a first aspect of the invention, wherein after a first back-extraction (when carried out with hydrochloric acid), the uranium- and / or scandium-rich organic phase is additionally washed with sulfuric acid. Washing with sulfuric acid allows for the removal of residual chloride ions and possibly residual extracted metals other than uranium and scandium from the solvent.

[0124] In a preferred embodiment, the invention provides a method according to a first aspect of the invention, wherein nickel and cobalt are eluted from the uranium- and / or scandium-rich organic phase prior to back-extraction with first and second back-extraction fluids. To recover the co-extracted nickel and cobalt from the loaded organic phase before entering the elution section, they are first selectively eluted from these solvents by washing with an acidic solution (e.g., a sulfuric acid solution in water). Nickel and cobalt are selectively eluted by applying optimal pH conditions (specifically, the acidity of the final eluent solution), and the amount of acid added is adjusted to achieve the desired pH.

[0125] In a preferred embodiment, the organic phase is back-extracted continuously using a first back-extraction fluid (S1), while a second back-extraction fluid (S2) is used only periodically to remove uranium and / or scandium from the organic phase. More specifically, the second back-extraction fluid is applied to the organic phase when the concentration of uranium and / or scandium in the organic phase is higher than 0.5 g / L, more specifically higher than 1 g / L, or even more specifically higher than 2 g / L. In this way, the accumulation of uranium and / or scandium on the organic phase is stopped, and the solvent extraction capacity of the organic phase is controlled.

[0126] In another preferred embodiment, the second aqueous eluent (E2) enriched with uranium and / or scandium, obtained after back-extraction of the organic phase with the second back-extraction fluid (S2), is reintroduced upstream of the method, more preferably before step ii., and most preferably before step i. More specifically, the reintroduction of the aqueous eluent (E2) to step i. has the advantage of using acid for leaching. Such a method has the additional advantage that uranium and / or scandium exits the method only via uranium and / or scandium precipitates, while trace amounts of uranium and / or scandium are trapped on the organic phase without producing a dilute waste solution containing uranium and / or scandium.

[0127] In a preferred embodiment, the second back-extraction fluid (S2) is sulfuric acid, and an aqueous eluent (E2) is introduced back into step i.

[0128] In a preferred embodiment, the second back-extraction fluid (S2) is hydrochloric acid, and the aqueous eluent (E2) is introduced back into step i.

[0129] In a preferred embodiment, the second back-extraction fluid (S2) is phosphoric acid, and an aqueous eluent (E2) is introduced back into step ii.

[0130] In a preferred embodiment, the second back-extraction fluid (S2) is phosphoric acid, and the aqueous eluent (E2) is introduced back into step iii.

[0131] In a preferred embodiment, the method of the present invention is a continuous method, wherein back-extraction of the organic phase is performed continuously using a first back-extraction fluid (S1) and subsequently a second back-extraction fluid (S2) to remove uranium and / or scandium from the organic phase. A second eluent (E2) enriched with uranium and / or scandium is continuously reintroduced into leaching step i. Thus, the uranium and / or scandium content on the organic phase will evolve into a constant steady-state concentration.

[0132] This invention provides a method for preparing an aqueous solution containing nickel and / or cobalt and having a reduced or removed uranium and / or scandium content. In particular, due to the use of solvent extraction, uranium and / or scandium are almost completely removed from the final solution. The uranium content (if present in the solid feed material) in the aqueous raffinate obtained in step v. is preferably less than 5 mg / L, more preferably less than 1 mg / L, and even more preferably less than 0.1 mg / L. The scandium content (if present in the solid feed material) in the aqueous raffinate obtained in step v. is preferably less than 5 mg / L, more preferably less than 1 mg / L, and even more preferably less than 0.1 mg / L.

[0133] The method of the present invention is particularly suitable for providing concentrated nickel sulfate solutions, i.e., aqueous nickel sulfate solutions 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 sulfate solution obtained in the method of the present invention is a nickel sulfate solution having a nickel content of between 110 and 140 g / L, more preferably between 120 and 140 g / L, and most preferably the nickel sulfate solution has a nickel content of about 130 g / L.

[0134] The method of the present invention is also suitable for providing concentrated cobalt sulfate solutions, i.e., aqueous cobalt sulfate solutions 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 sulfate solution is a cobalt sulfate solution having a cobalt content between 110 and 140 g / L, more preferably between 120 and 140 g / L, and most preferably the cobalt sulfate solution has a cobalt content of about 130 g / L.

[0135] In a preferred embodiment of the invention, the method includes one or more further solvent extraction steps or other purification steps to obtain a nickel or cobalt salt with battery-grade purity, such a solution containing at least 99 atomic% Ni or Co relative to the total amount of metal in the solution. Preferably, such a solution has at least 99.5 atomic% Ni or Co, and more preferably at least 99.9 atomic% Ni or Co.

[0136] Example

[0137] The following examples are intended to further illustrate the invention and are in no way intended to limit the scope of the invention.

[0138] Example 1

[0139] like Figure 1 The continuous process is performed as described. In the first step, a solid feed consisting of MHP products is leached in a reactor containing water and sulfuric acid as a mineral acid (step i.) to obtain a solution containing uranium, aluminum, iron, nickel, and cobalt. The pH of this solution is then increased to 4 (step ii.), which results in the precipitation of iron and aluminum. Subsequently, a phosphate compound is added in approximately 100 times stoichiometric excess relative to the amount of uranium ions present (step iii.) while maintaining the pH at 4, which results in the precipitation of approximately 33% of the uranium atoms present. The precipitate containing uranium, iron, and aluminum is then filtered off (step iv.). The resulting solution containing nickel, cobalt, and the remaining uranium is subjected to solvent extraction using D2EHPA as an alkyl phosphate extractant (step v.). The organic phase absorbs almost all of the remaining uranium along with several other impurities, while nickel and cobalt remain primarily in solution.

[0140] Metals other than uranium were back-extracted from the solvent by a multi-stage back-extraction method using a 200 g / L H2SO4 solution as the first back-extraction fluid (S1), resulting in a first eluent (E1) with a final concentration of approximately 10 g / L H2SO4.

[0141] Subsequently, a single-stage batch process is performed to back-extract a portion of the uranium from the solvent. The second back-extraction fluid (S2) and the second eluent (E2) have a concentration of approximately 500 g / L of H2SO4. The solvent is reused for extraction, and the uranium-enriched second eluent (E2) is reintroduced into the leaching step.

[0142] Once steady state is reached, the uranium concentration after the leaching step is approximately 7.5 mg / L. The uranium concentration is reduced to approximately 5 mg / L via phosphate precipitation. The uranium concentration on the solvent is approximately 0.5 g / L, and the output aqueous raffinate contains < 1 mg / L of uranium.

[0143] Example 2

[0144] Provide MHP products with the composition according to Table 1.

[0145] Table 1. MHP composition relative to the dry weight of the composition.

[0146]

[0147] (1) Expressed in ppm.

[0148] In the first step, MHP is leached in a reactor containing water and sulfuric acid. A reducing agent is added to increase the leaching yield. Once the solid contents are dissolved in the aqueous medium, the pH of the solution is increased to 4 by slowly adding calcium carbonate. A precipitate containing iron and aluminum is formed, while nickel and uranium remain primarily in the solution.

[0149] Subsequently, phosphoric acid was added in a ratio of 250:1 relative to the amount of uranium in the resulting leachate solution to form a uranium precipitate in the leachate. The pH was maintained at approximately 4 to prevent the redissolution of iron and aluminum. The precipitate containing iron, aluminum, and uranium was then filtered off. Analysis of the filtrate indicated a reduction of approximately 85% in the amount of uranium relative to the uranium content in the MHP.

[0150] Subsequently, the filtrate was subjected to solvent extraction, thereby significantly reducing the amount of uranium.

[0151] Example 3

[0152] Provide CHIP products with the composition according to Table 2.

[0153] In the first step, CHIP is leached in a reactor containing water and a 1:1 mixture of hydrochloric acid and sulfuric acid. Once the solid contents are dissolved in the aqueous medium, the pH of the solution is increased to 4.2 by the slow addition of nickel carbonate. A precipitate containing iron and aluminum is formed, while nickel and uranium remain in the solution.

[0154] Subsequently, NaH₂PO₄ was added to the eluent to form a uranium precipitate in the leaching solution. The uranium-containing precipitate was then filtered off. The uranium precipitate was subjected to a reduction process to recover uranium. Analysis of the filtrate indicated that the amount of uranium was reduced by approximately 60% relative to the uranium content in the CHIP.

[0155] Subsequently, the filtrate was subjected to solvent extraction, thereby significantly reducing the amount of uranium.

[0156] Table 2. CHIP composition relative to the dry weight of the composition.

[0157]

[0158] (1) Expressed in ppm.

[0159] Example 4

[0160] The MHP product is leached, and after precipitating iron, aluminum, and a portion of uranium, a solution with the following composition is obtained and fed as feed to a solvent extraction method for further purification:

[0161] Table 3. Composition of feed and raffinate in the solvent extraction step.

[0162]

[0163] An organic phase consisting of 25% (v / v) D2EHPA and Escaid 110 as a diluent was used. The extractant was saponified with 400 g / L NaOH at 49%. Extraction of uranium and other impurities was carried out in batch mode, in four steps, at O / A = 0.25, and at 30 °C. The composition of the raffinate is also reported in the table above. Manganese, calcium, and zinc were removed from the raffinate to less than 1 mg / L, and uranium was also removed to <1 mg / L.

[0164] Example 5

[0165] The MHP feed was continuously leached, and purified by precipitation and solvent extraction to remove iron, aluminum, and uranium. The organic phase was back-extracted with a first back-extraction fluid, and the uranium-enriched solvent was reused for extraction. When the uranium concentration in the solvent reached 1.29 or 2.86 g / L, a second back-extraction fluid was applied as follows: a single-stage batch process was performed at 1 O / A and 40°C to back-extract the organic phase consisting of 30 vol% D2EHPA and Escaid 110 as a diluent. The initial uranium concentration in the solvent, the acid concentration of the second back-extraction fluid, and the percentage of uranium transferred to the aqueous eluent were as follows:

[0166] Table 4. Extraction of uranium from solvent.

[0167]

[0168] Example 6a

[0169] The MHP product, containing nickel, cobalt, iron, aluminum, and uranium, was leached, and after precipitating iron, aluminum, and some uranium using a phosphate compound, the solution was fed as feed to a solvent extraction method using Alamine 336 as the extractant. The use of this extractant achieved a significant further reduction in uranium content.

[0170] Example 6b

[0171] The MHP product, containing nickel, cobalt, iron, aluminum, and uranium, is leached, and after the iron, aluminum, and some uranium are precipitated using a phosphate compound, the solution is fed as feed to a solvent extraction method using tributyl phosphate as the extractant. The use of this extractant achieves a further reduction in uranium content.

[0172] Example 6c

[0173] The MHP product, containing nickel, cobalt, iron, aluminum, uranium, and scandium, is leached, and after the iron, aluminum, and some of the uranium and scandium are precipitated using a phosphate compound, the solution is fed as feed to a solvent extraction method using PC88A as the extractant. The use of this extractant achieves a significant further reduction in the uranium and scandium content.

[0174] Example 7

[0175] like Figure 2 The continuous process is performed as described. In the first step, a solid feed containing uranium and scandium is leached in a reactor containing water and sulfuric acid as a mineral acid (step i.), thereby obtaining a solution containing uranium, scandium, aluminum, iron, nickel, and cobalt. The pH of this solution is then increased to 4 (step ii.), which causes iron and aluminum, as well as approximately 35% of the scandium present in the leachate solution, to precipitate. Subsequently, a phosphate compound is added in stoichiometric excess relative to the total amount of uranium and scandium in the solid feed material, while maintaining the pH at 4, which causes approximately 33% of the uranium atoms present and approximately 99% of the scandium ions present (including the precipitate of Sc from step ii.) to precipitate. The precipitate containing uranium, scandium, iron, and aluminum is then filtered off (step iv.). The resulting solution containing nickel, cobalt, and the remaining uranium and scandium is subjected to solvent extraction using D2EHPA as an alkyl phosphate extractant (step v.). The organic phase absorbs almost all the remaining uranium and scandium along with several other impurities, while nickel and cobalt remain mainly in solution.

[0176] Metals other than uranium and scandium are back-extracted from the solvent by a multi-stage back-extraction method using a first back-extraction fluid (S1) to obtain a first eluent (E1).

[0177] Subsequently, a single-stage batch process is performed using a second back-extraction fluid (S2) to back-extract a portion of the uranium and scandium from the solvent, yielding a second eluent (E2). The second eluent has a higher acid concentration than the first eluent. The solvent is reused for extraction, and the uranium- and scandium-enriched second eluent (E2) is reintroduced into the leaching step.

[0178] The output aqueous raffinate contains significantly reduced amounts of uranium and scandium.

[0179] Example 8

[0180] MHP products with the composition according to Table 5 are provided.

[0181] Table 5. MHP composition relative to the dry weight of the composition.

[0182]

[0183] (1) Expressed in ppm.

[0184] In the first step, MHP is leached in a reactor containing water and sulfuric acid. A reducing agent is added to increase the leaching yield. Once the solid contents are dissolved in the aqueous medium, the pH of the solution is increased to 4 by the slow addition of calcium carbonate. A precipitate containing iron and aluminum is formed, while nickel and uranium remain primarily in the solution. Scandium is distributed in both the precipitate (approximately 35%) and the solution (approximately 65%).

[0185] Subsequently, phosphoric acid was added in a ratio of 250:1 relative to the amount of uranium in the obtained leaching solution to form a precipitate of uranium and scandium in the leaching solution. The pH was maintained at approximately 4 to prevent the redissolution of iron and aluminum. The precipitate containing iron, aluminum, uranium, and scandium was then filtered off. Analysis of the filtrate indicated a reduction of approximately 85% in the amount of uranium relative to the uranium content in the MHP, and a reduction of approximately 99% in the amount of scandium relative to the uranium content in the MHP.

[0186] The filtrate was then subjected to solvent extraction, thereby further reducing the amounts of uranium and scandium.

[0187] Example 9

[0188] like Figure 3 The continuous process is performed as described. In the first step, a solid feed containing approximately 500 ppm scandium (step i.) is leached in a reactor containing water and sulfuric acid as a mineral acid to obtain a solution containing scandium, aluminum, iron, nickel, and cobalt. The leaching solution has a pH of approximately 2 and contains approximately 140 mg / L of scandium. The pH of the solution is increased to 4 by slowly adding calcium carbonate and maintained at 60°C. A precipitate containing iron, aluminum, and scandium is formed. Scandium is distributed in the precipitate (approximately 35%) and the solution (approximately 65%). Subsequently, 0.5 L of 85% wt% H3PO4 solution / m 3 The amount of phosphoric acid obtained from the leachate solution was adjusted to form a scandium precipitate in the leachate. The pH was maintained at approximately 4 to prevent the redissolution of iron and aluminum. The precipitate containing iron, aluminum, and scandium was then filtered off. Analysis of the filtrate indicated a reduction in scandium content of approximately 99% relative to the scandium content in the MHP.

[0189] Subsequently, the filtrate is subjected to solvent extraction, thereby further reducing the amount of scandium.

Claims

1. A method for preparing a salt solution of nickel and / or cobalt, the method comprising the following steps: i. Leaching a solid material feed containing uranium and / or scandium, at least 20% by weight of nickel and cobalt relative to the total dry weight of the solid material feed, and at least 0.05% by weight of iron and aluminum in an aqueous medium with a mineral acid selected from the group consisting of H2SO4, HCl and HNO3, thereby obtaining a leachate solution containing uranium and / or scandium ions and at least one of nickel ions and cobalt ions, respectively. ii. Increase the pH of the leachate solution to at least 2.5, thereby precipitating iron and / or aluminum compounds and obtaining an alkalized leachate solution; iii. Simultaneously with or after step ii., add a phosphate compound to the alkalized leaching solution from step ii. to form uranium and / or scandium precipitates; iv. Separate the precipitate formed in step iii. from the leachate solution to obtain an aqueous solution containing at least one of uranium and / or scandium and nickel and cobalt ions; as well as v. Extracting uranium and / or scandium from the aqueous solution obtained in step iv. into an organic phase containing an extractant and a diluent, thereby obtaining an organic phase enriched with uranium and / or scandium, and an aqueous raffinate containing at least one of nickel ions and cobalt ions.

2. The method according to claim 1, wherein the uranium and / or scandium-enriched organic phase obtained in step v. is treated with a first back-extraction fluid (S1) and subsequently with a second back-extraction fluid (S2) to obtain a first aqueous eluent (E1) and a second aqueous eluent (E2) enriched with uranium and / or scandium, respectively, wherein the second aqueous eluent (E2) has a higher acid concentration than the first aqueous eluent (E1).

3. The method according to claim 2, wherein the first back-extraction fluid (S1) has an acid concentration of 0.5 M to 5 M, and wherein the second back-extraction fluid (S2) has an acid concentration of 2 M to 10 M.

4. The method according to claim 2 or 3, wherein the first back-extraction fluid and the second back-extraction fluid comprise a mineral acid selected from sulfuric acid, hydrochloric acid and phosphoric acid.

5. The method according to any one of claims 2 to 4, wherein the organic phase is treated with first and second back-extraction fluids at a temperature between 20 and 55°C.

6. The method according to any one of claims 2 to 5, wherein the second aqueous eluent (E2) for enriching uranium and / or scandium is introduced upstream of the method.

7. The method according to any one of claims 1 to 6, wherein the extractant comprises an alkylphosphine-based extractant, preferably an alkylphosphine and / or its derivatives.

8. The method according to any one of claims 1 to 7, wherein the phosphate compound is selected from H3PO4 and contains H2PO4. - HPO4 2- Or PO4 3- A group composed of compounds.

9. The method according to any one of claims 1 to 8, wherein in step ii.(a) the pH of the leachate solution is increased to between 2.5 and 4.5, and wherein in step ii.(b) the pH of the alkalized leachate solution from step ii.(a) is increased to between 4.5 and 6.0, and wherein the precipitate formed in step ii.(a) is filtered out prior to step ii.(b).

10. The method according to any one of claims 1 to 9, wherein the pH in step ii. is increased by adding a Ca base and / or a Ni base.

11. The method according to any one of claims 1 to 10, wherein the precipitate containing iron and / or aluminum formed in step ii. is not separated from the alkalized leachate solution before the addition of the phosphate in step iii.

12. The method according to any one of claims 1 to 11, wherein the solid material feed comprises a mixed hydroxide precipitate or a cobalt hydroxide intermediate precipitate.

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