CN117642519A

CN117642519A - Production of high purity nickel and cobalt compounds

Info

Publication number: CN117642519A
Application number: CN202280049760.4A
Authority: CN
Inventors: 张文胜
Original assignee: Commonwealth Scientific and Industrial Research Organization CSIRO
Current assignee: Commonwealth Scientific and Industrial Research Organization CSIRO
Priority date: 2021-05-13
Filing date: 2022-05-13
Publication date: 2024-03-01
Also published as: EP4337802A1; JP2024520304A; AU2022271919A1; WO2022236381A1; KR20240019147A

Abstract

A process for separating nickel and/or cobalt salts from nickel and/or cobalt containing raw materials is disclosed. The method comprises the following steps: treating the nickel and/or cobalt containing raw material with iron or aluminium salts under conditions for removing at least some of the one or more alkali metal ions and/or monovalent cation species in the form of jarosite/alunite precipitate to provide a reduced content solution of the one or more alkali metal ions and/or monovalent cation species; and subjecting the obtained solution to a pH increase in a stepwise manner under conditions for providing a feed solution for further purification to produce a nickel and/or cobalt salt suitable for producing a battery grade nickel or cobalt salt. A process for obtaining purified nickel and cobalt from a feed solution is also disclosed.

Description

Production of high purity nickel and cobalt compounds

Cross Reference to Related Applications

The present application claims priority from australian provisional patent application No. 2021901424 entitled "production of high purity nickel and COBALT COMPOUNDS (PRODUCTION OF HIGH PURITY NICKEL AND cobalat components)" filed on month 13 of 2021, the contents of which are hereby incorporated by reference in their entirety.

Technical Field

The present invention relates to a process for obtaining high purity nickel and cobalt compounds from nickel and cobalt containing raw materials.

Background

High purity nickel sulfate and cobalt sulfate are important precursors for forming lithium battery cathodes, which are typically formed from nickel-cobalt-manganese (NCM) and nickel-cobalt-aluminum (NCA).

There is currently no standard for high purity, battery grade nickel sulfate and cobalt sulfate. However, example high purity or battery grade nickel sulfate hexahydrate (NiSO) with low levels of trace elements (e.g., al, ca, cd, co, cr, cu, fe, mg, mn, na, pb, si and Zn) is shown in table 1 _4. 6H ₂ O)。

TABLE 1 high purity or Battery grade Nickel sulfate hexahydrate (NiSO) _4. 6H ₂ O) example specifications.

Typical high purity or battery grade nickel sulfate hexahydrate (NiSO) with low levels of trace elements is shown in table 2 _4. 6H ₂ O)。

TABLE 2 high purity or Battery grade Nickel sulfate hexahydrate (NiSO) _4. 6H ₂ O) typical specifications.

Nickel, in% Ni	22-23
		Cobalt, in Co, ppm	<50
Manganese, in Mn, ppm	<5
		Iron, in Fe, ppm	<5
Copper, in Cu, ppm	<5
		Sodium, in Na, ppm	<20
Calcium, in Ca, ppm	<10
		Magnesium, in Mg, ppm	<20
Zinc, in Zn, ppm	<5
		Lead, in Pb, ppm	<5
Chromium, in the form of Cr,ppm	<5
		cadmium, in Cd, ppm	<5
Aluminum, in Al, ppm	<5
		Silicon, in Si, ppm	<10

Similarly, an example high purity or battery grade cobalt sulfate heptahydrate (CoSO) with low levels of trace elements (e.g., al, ca, cd, cr, cu, fe, mg, mn, na, ni, pb, si and Zn) is shown in table 3 _4. 7H ₂ O)。

TABLE 3 high purity or Battery grade cobalt sulfate heptahydrate (CoSO _4. 7H ₂ O) example specifications.

Cobalt, as Co%	>20.5
		Manganese, in Mn, ppm	<10
Iron, in Fe, ppm	<10
		Nickel, in Ni, ppm	<100
Copper, in Cu, ppm	<10
		Sodium, in Na, ppm	<25
Calcium, in Ca, ppm	<25
		Magnesium, in Mg, ppm	<20
Zinc, in Zn, ppm	<10
		Lead, in Pb, ppm	<10
Chromium, in Cr, ppm	<10
		Cadmium, in Cd, ppm	<10
Aluminum, in Al, ppm	<10
		Silicon, in Si, ppm	<10

Typical high purity or battery grade cobalt sulfate heptahydrate (CoSO) with low levels of trace elements are shown in table 4 _4· 7H ₂ O)。

TABLE 4 high purity or Battery grade cobalt sulfate heptahydrate (CoSO _4· 7H ₂ O) typical specifications.

Cobalt, as Co%	20.5-22
		Manganese, in Mn, ppm	<5
Iron, in Fe, ppm	<5
		Nickel, in Ni, ppm	<50
Copper, in Cu, ppm	<5
		Sodium, in Na, ppm	<20
Calcium, in Ca, ppm	<20
		Magnesium, in Mg, ppm	<10
Zinc, in Zn, ppm	<5
		Lead, in Pb, ppm	<5
Chromium, in Cr, ppm	<5
		Cadmium, in Cd, ppm	<5
Aluminum, in Al, ppm	<5
		Silicon, in Si, ppm	<10

Traditionally, nickel sulphide has been an important starting material for use in battery grade nickel sulphate production, but as nickel sulphide deposits continue to run out, low grade laterite nickel deposits (73% of the global nickel resources) are becoming an increasingly important source of both nickel and cobalt for the battery industry. However, profitable processing of these lower laterites to produce high purity, battery grade nickel sulfate and cobalt sulfate has been difficult to achieve. Existing refining processes for producing high purity, battery grade nickel and cobalt sulphate either require a costly step of physically extracting the main metal (i.e. nickel) from relatively small amounts of the relevant impurities (typically, impurity to nickel mass ratio < 1/15) by solvent extraction (SX), or can only produce nickel liquor suitable for producing other forms of nickel products, typically nickel cathodes obtained by electrolytic deposition or nickel powders obtained by hydrogen reduction. These forms of nickel products in turn require further refining processes to produce high purity, battery grade nickel sulfate.

Laterite nickel ores are usually treated by direct acid leaching, followed by precipitation of the main iron and aluminum impurities in an enriched leach solution (PLS) by neutralization or thermal hydrolysis. Nickel and cobalt are then typically recovered as an intermediate product, either Mixed Sulfide Precipitate (MSP) or Mixed Hydroxide Precipitate (MHP), using an alkaline chemical such as magnesium oxide, lime, limestone or sodium hydroxide. MHP processes are becoming more and more popular than MSP processes that can reject more common impurities because they eliminate the costly and undesirable H associated with MSP processes ₂ S precipitation step and which yields a product that is readily soluble in ammonia or acid, which aids in the purification and recovery process. Since the specifications of battery grade nickel and cobalt sulphate require very low levels of impurities, the process for separating and purifying these nickel and cobalt sulphate from PLS formed by dissolving raw materials such as MHP is of great importance.

Although there are several existing commercial hydrometallurgical processes for treating laterite nickel ores and subsequently refining intermediate products (such as MSP and MHP), the products from these processes require further purification to meet the required specifications for battery grade nickel and cobalt products. Even though the nickel metal powder produced during hydrogen reduction is LME grade, it still requires further purification to produce battery grade nickel sulfate.

Generally, known commercial nickel laterite processes can be classified into acid-based processes and alkali-based processes.

A typical alkaline leaching process is the modified Caron process (Caron process), which uses an ammonia-ammonium carbonate leaching agent, and has been previously adopted by nickel and cobalt refineries of Kunsland Nickel (Queensland Nickel Industries, QNI) and Coos Nickel (Cawse Nickel Operations) (Fittok, 1992; fittok et al, 1994; price and Reid, 1987). The refining sector of these plants re-leaches MHP with ammonia under mild reducing conditions and then uses84 ketoxime was subjected to solvent extraction to isolate nickel (Virnig et al, 1997). Nickel is precipitated from the solution as carbonate and calcined to nickel oxide which is further processed into a range of products such as nickel metal produced by hydrogen reduction. Cobalt is recovered from the nickel depleted raffinate by precipitation of cobalt sulfide using sodium hydrosulfide. The cobalt product may be further processed to produce a high purity cobalt product.

Mi Nala Merlin from Minara ResourcesCompany (Murrin Murrin Operations) employs a High Pressure Acid Leaching (HPAL) process (Rodriguez, 2008; rodriguez, 2009). MSP is produced to remove a large number of impurities (such as aluminum, magnesium, and manganese) found in the leachate. Redissolving the MSP in the presence of oxygen and passing the liquid through the use of two The 272 loop is subjected to solvent extraction (SX) for removal of zinc and then cobalt for purification to produce a raffinate containing nickel, which is recovered as metallic nickel by hydrogen reduction.

A problem with existing processes is that they cannot produce acceptable nickel and/or cobalt liquor for direct crystallization of high purity, battery grade nickel and/or cobalt sulphate, or that the process involves costly steps for extracting and separating the primary metallic nickel from relatively small amounts of impurities in PLS.

There are also challenges and limitations associated with the separation of some related impurities such as alkali metals (Na and K) that are present with nickel in nickel ores and other nickel-containing materials and then enter PLS after leaching and subsequently intermediate products such as MHP. If sodium hydroxide or ammonium hydroxide is used for the neutralization and precipitation of MHP, more sodium ions or monovalent species such as ammonium ions may be introduced into MHP.

The precipitated MHP may be washed to partially remove soluble species. In Canadian patent application No. 2949580-A1 and Australian patent application No. 2016256773-A1 (Clout and Perry), the wash of MHP is included in the process as a step for removing or partially removing magnesium, calcium, sulfate, chloride and sodium components from MHP, but this is typically done in order to reduce the level of soluble impurities in the leachate to meet the need for integration into existing ammonia pressure leaching processes, thereby producing the corresponding cobalt and nickel powders by pressure reduction with hydrogen.

Separation of cobalt from nickel generally requires the use of an organic phosphinic acid such as272 solventExtraction, where alkaline reagents (typically sodium hydroxide and ammonia/ammonium hydroxide) are required for neutralization of the equivalent amount of acid produced during the SX process or for pH control. Alkali metal ions and ammonium ions are eventually present in the raffinate along with nickel and some alkaline earth metals such as calcium and magnesium, which can cause contamination by forming complex salts of sulfuric acid including these impurities if the raffinate is used directly for crystallization of nickel sulfate.

The problem with the direct addition of ammonia to the concentrated nickel sulfate solution in SX is the formation of nickel ammonium sulfate double salts. Attempts have been made in the prior art to solve this problem by preneutralization of the organophosphate extractant and/or by preloading the organic phase with nickel.

In addition, most methods and schemes for pre-neutralization and pre-loading are developed to prevent formation of nickel double salts during cobalt SX with high concentration nickel sulfate solution, and the nickel raffinate from cobalt SX is recovered as nickel cathode by electrodeposition or as metallic nickel by hydrogen reduction in the ammoniation process (ammoniacal process). Although some prior art schemes have utilized pre-neutralization and pre-loading methods to minimize contamination of the cobalt and nickel main streams with alkali metal and ammonium ions introduced from the neutralization in the form of alkaline reagents, the cobalt and nickel liquors obtained by these schemes are severely contaminated with these impurities and are unsuitable for use in producing high purity, battery grade nickel sulfate.

As is apparent from the foregoing description, the nickel produced in these processes tends to be severely contaminated and the process does not provide for complete and adequate separation of the separate magnesium, cobalt and nickel streams to enable the production of high purity, battery grade nickel and cobalt sulfate.

Furthermore, current practice for producing high purity, battery grade nickel sulfate involves the use of an organic carboxylic acid (typically10 Nickel is subjected to solvent extraction for separating the nickel from alkali metals, ammoniacal species and alkaline earth metals (e.g., calcium and magnesium). The step involving mainly metallic nickel SX is very expensive and it occupies the refining processA major portion of the total operating and capital costs.

An integrated process is needed to convert nickel/cobalt mixed hydroxide intermediates (e.g., MHP) or other nickel-containing materials or solutions to high purity, battery grade nickel sulfate and cobalt sulfate without the need for costly separation steps of the primary metal nickel. Alternatively or additionally, there is a need for a process for producing high purity, battery grade nickel sulfate and cobalt sulfate that overcomes one or more of the problems associated with prior art or known processes. Alternatively or additionally, there is a need for a useful alternative to existing processes for producing high purity nickel sulfate and cobalt sulfate.

Disclosure of Invention

The present invention arose from the inventors' study of a process for converting nickel/cobalt mixed hydroxide intermediates (such as MHP) or other nickel-containing materials or solutions to high purity, battery grade nickel and cobalt sulfate. The process described herein can generally be performed in two stages.

In the first stage of the process described herein, laterite nickel ore, other nickel-containing materials, intermediates (such as MHP), or nickel-containing solutions are converted to feed solutions that are substantially free of alkali metal and monovalent cation species and suitable for further purification processes to produce high purity, battery grade nickel sulfate. This first stage may involve retrofitting existing laterite nickel ore or other nickel containing material upstream processing to efficiently produce feed solution or MHP suitable for subsequent refining processes. Optionally, a portion or preferably a major portion of the manganese may be converted to stable Mn (III/IV) oxide in MHP or in the leach slurry, and then the Mn (III/IV) oxide is separated to produce an easily purified feed solution with reduced manganese content to produce high purity, battery grade nickel sulfate.

Accordingly, in a first aspect, there is provided a process for separating nickel and/or cobalt salts from a nickel and/or cobalt containing crude material, the process comprising:

a) Treating the nickel and/or cobalt containing raw material with iron or aluminium salts under conditions for removing at least some of the one or more alkali metal ions and/or monovalent cation species in the form of jarosite/alunite precipitate to provide a reduced content solution of the one or more alkali metal ions and/or monovalent cation species;

b) Subjecting the solution from step a) to a pH increase in a stepwise manner under conditions for providing a feed solution for further purification to produce nickel and/or cobalt salts suitable for producing battery grade nickel or cobalt salts;

wherein step b) removes at least some or any combination of any one or more of the following species:

i. the iron is used for the production of the steel,

aluminum is used as a base material for the aluminum alloy,

chromium (Cr)

Copper.

In certain embodiments of the first aspect, the method of the first aspect further comprises treating the nickel and/or cobalt containing raw material with an aqueous solution comprising water and/or sulfuric acid under conditions for removing at least some of the one or more alkali metal ions and/or monovalent cation species prior to step a). The step of treating the nickel and/or cobalt containing crude material with an aqueous solution comprising water and/or sulfuric acid may be performed at a pH of 7 or higher.

In certain embodiments of the first aspect, the feed solution is treated with an oxidant under conditions for oxidizing any iron (II) to iron (III) and any manganese (II) to manganese (III/IV) in a higher oxidation state to provide a feed solution containing nickel and/or cobalt and having a reduced concentration of any one or more of alkali metal ions, monovalent cation species, iron, aluminum, chromium, copper, and manganese relative to the nickel and/or cobalt containing raw material.

In certain embodiments of the first aspect, the iron or aluminum salt in step a) is a sulfate, carbonate, oxide or hydroxide of iron and/or aluminum.

In the second stage of the process described herein, a novel solvent extraction (SX) process is provided with minimal SX systems and circuitry for separating impurities from cobalt and nickel and separating cobalt from nickel to produce a crystallized cobalt liquor suitable for high purity, battery grade cobalt sulfate, cobalt chloride, cobalt nitrate or other cobalt products if desired, and a directly crystallized nickel raffinate suitable for high purity, battery grade nickel sulfate or other nickel products if desired, without the need for a major metallic nickel separation step. Advantageously, the second stage process avoids contamination caused by neutralization of the SX process with an alkaline reagent such as sodium hydroxide, sodium carbonate, ammonia or ammonium hydroxide. The second stage process provides an alternative process that enables direct neutralization during solvent extraction with ammonia/ammonium hydroxide and selective removal of the ammonium component from the final hydrated nickel sulfate as ammonia that is recycled as an alkaline reagent in the process.

Accordingly, in a second aspect there is provided a process for obtaining purified nickel and cobalt from a feed solution obtained according to the first aspect, the process comprising:

a) Reducing the concentration of any zinc, calcium, manganese, copper, cadmium, lead or other metal impurities in the feed solution having a higher affinity for the organic extractant than cobalt and nickel by contacting the feed solution with an organic phosphoric acid extractant in a hydrocarbon diluent under solvent extraction conditions, and separating the organic phase and the aqueous phase to produce an aqueous raffinate comprising purified cobalt and nickel;

b) Contacting an aqueous raffinate comprising purified cobalt and nickel with a cobalt selective extractant in a hydrocarbon diluent under solvent extraction conditions and separating the organic phase and the aqueous phase to produce an organic phase comprising purified cobalt and an aqueous phase comprising purified nickel, and then selectively eluting and stripping the organic phase to obtain an aqueous phase comprising purified cobalt;

c) Purifying the aqueous phase comprising purified cobalt to produce a further aqueous phase comprising purified cobalt;

d) Recovering cobalt from the further aqueous phase; and

e) Nickel is recovered from the aqueous phase comprising purified nickel.

It will be appreciated that the first and second stages described herein above may be performed separately from each other or they may be combined to provide an improved process for producing high purity, battery grade cobalt sulfate or other cobalt products and high purity, battery grade nickel sulfate from nickel and cobalt containing raw materials such as laterite ores.

In certain embodiments of the second aspect above, step b) comprises:

a) (i) co-extracting both cobalt and magnesium in the aqueous raffinate from step a) into the organic phase; (ii) Selectively eluting any co-extracted nickel from the organic phase with an eluting solution of sulfuric acid and/or cobalt sulfate at a relatively high equilibrium pH range to obtain a nickel-depleted organic phase and a nickel-rich eluting solution (aqueous phase), the nickel-rich eluting solution being recycled to step (i); (iii) Further eluting magnesium selectively from the organic phase with sulfuric acid and/or an eluting solution of cobalt sulfate at a relatively low equilibrium pH range to obtain an organic phase with purified cobalt and a magnesium rich eluting solution (aqueous phase); (iv) Re-extracting any co-stripped cobalt in the magnesium-rich eluent (aqueous phase) with a small portion of the organic phase to obtain a small portion of the cobalt-loaded organic phase which is incorporated into the major portion of the organic phase in step (iii); and (v) stripping the organic phase from step (iii) to produce an aqueous phase comprising purified cobalt; or (b)

b) (i) selectively extracting cobalt from the aqueous raffinate from step a) into an organic phase; (ii) Eluting both co-extracted nickel and magnesium in the organic phase with an eluting solution of sulfuric acid and/or cobalt sulfate to obtain an organic phase with purified cobalt and an eluting solution (aqueous phase) enriched in nickel and magnesium, which eluting solution is recycled to step (i); (iii) Stripping cobalt from the purified organic phase from step (ii) with an acid to obtain an aqueous phase (stripping solution) comprising purified cobalt; (iv) Selectively extracting magnesium from the step (i) raffinate with a portion of the organic solution to obtain an aqueous phase comprising purified nickel (final raffinate) and a magnesium-rich organic phase; (v) Eluting any co-extracted nickel in the organic phase with an elution solution of sulfuric acid to obtain a nickel rich elution solution, which is recycled to step (iv); and (vi) stripping the magnesium-rich organic phase to obtain an aqueous phase comprising purified magnesium for recovery of magnesium by-products.

In certain embodiments of the second aspect, the organophosphate extractant has the formula (RO) ₂ PO ₂ H, each of whichEach R group, which may be the same or different, is an optionally substituted branched, straight or cyclic alkyl, alkenyl or alkynyl group.

In certain embodiments of the second aspect, the organophosphate extractant is di-2-ethylhexyl phosphoric acid (D2 EHPA) or an organophosphate having similar or identical extraction characteristics to that of di-2-ethylhexyl phosphoric acid, such as mono-2-ethylhexyl phosphoric acid (M2 EHPA) or di-p-octylphenyl phosphoric acid (OPPA).

In certain embodiments of the second aspect, the cobalt selective extractant is of formula R ₂ PO ₂ The organic phosphinic acids of H, wherein each R group, which may be the same or different, is selected from optionally substituted branched, straight or cyclic alkyl, alkenyl or alkynyl groups.

In certain embodiments of the second aspect, the cobalt selective extractant is di-2, 4-trimethylpentylphosphinic acid or an organic phosphinic acid having similar or identical extraction characteristics to those of di-2, 4-trimethylpentylphosphinic acid, such as di-2-ethylhexyl phosphinic acid. By way of example only, di-2, 4-trimethylpentylphosphine acid is a commercial product272 and->290.

In certain embodiments of the second aspect, one or more phase modifiers may be present in the organic solution. The modifier may be any suitable modifier that improves separation of the organic and aqueous phases including, but not limited to, isodecyl alcohol, isotridecyl alcohol, 2-ethylhexanol, and tri-n-butyl phosphate.

In certain embodiments of the second aspect, the hydrocarbon diluent is an aliphatic or aromatic hydrocarbon solvent or a mixture thereof. In certain embodiments of the second aspect, the hydrocarbon diluent is kerosene.

In certain embodiments of the second aspect, step c) of purifying the aqueous phase comprising purified cobalt comprises:

contacting an aqueous phase comprising purified cobalt with an ion exchange (IX) resin under conditions for selectively binding impurities to the resin to form a loaded resin,

the loaded resin is washed with water and/or an aqueous acid solution to recover co-loaded cobalt. In certain embodiments, step c) above further comprises eluting the loaded resin with an acid to remove impurities and regenerate the resin.

In certain embodiments of the second aspect, step c) of purifying the aqueous phase comprising purified cobalt further comprises removing at least some of any copper from the aqueous phase comprising purified cobalt. The step of removing at least some of any copper from the aqueous phase comprising purified cobalt may comprise contacting the aqueous phase comprising purified cobalt with iminodiacetic acid resin under conditions for binding to copper, and separating the copper-loaded resin from the aqueous phase.

In certain embodiments of the second aspect, step c) of purifying the aqueous phase comprising purified cobalt further comprises removing at least some of any zinc from the aqueous phase comprising purified cobalt. The step of removing at least some of any zinc from the aqueous phase comprising purified cobalt may comprise contacting the aqueous phase comprising purified cobalt with a D2 EHPA-impregnated resin under conditions for binding to zinc and separating the zinc-loaded resin from the aqueous phase.

In certain embodiments of the second aspect, step c) of purifying the aqueous phase comprising purified cobalt optionally comprises simultaneously removing at least some of any zinc and at least some of any copper from the aqueous phase comprising purified cobalt. The step of simultaneously removing at least some of any zinc and at least some of any copper from the aqueous phase comprising purified cobalt may comprise contacting the aqueous phase comprising purified cobalt with an aminophosphonic acid resin under conditions for combining with zinc and copper, and separating the copper and zinc loaded resin from the aqueous phase.

In certain embodiments of the second aspect, step c) of purifying the aqueous phase comprising purified cobalt further comprises removing at least some of any manganese from the aqueous phase comprising purified cobalt. Removal of at least some of any manganese from an aqueous phase comprising purified cobalt The step of (a) may comprise contacting the aqueous phase comprising purified cobalt with an oxidant under conditions for oxidising any manganese (II) to manganese (III/IV) of higher oxidation state, and separating the solid manganese (III/IV) oxide from the aqueous phase. The oxidizing agent may be selected from the group consisting of ozone, SO at a ratio that acts as an oxidizing agent ₂ /O ₂ (air), peroxomonosulfuric acid (Caro's acid) and peroxodisulfuric acid (if the aqueous phase comprising purified cobalt is sulfate) or from the same other group of oxidizing agents (e.g. chlorides or nitrates) as the aqueous phase comprising purified cobalt.

In certain embodiments of the second aspect, step c) of purifying the aqueous phase comprising purified cobalt optionally comprises removing at least one of one or more of zinc, calcium, manganese, copper, cadmium, lead or other metal impurities in the aqueous phase comprising purified cobalt by contacting the aqueous phase comprising purified cobalt with an organophosphate extractant in a hydrocarbon diluent under solvent extraction conditions, optionally in the presence of a phase modifier, and separating the organic phase and the aqueous phase to produce a further aqueous phase comprising purified cobalt.

In certain embodiments of the second aspect, the step of recovering nickel from the aqueous phase comprising purified nickel comprises crystallizing nickel sulfate from the aqueous phase comprising purified nickel.

In certain embodiments of the second aspect, step a) of the method further comprises eluting at least some of any co-extracted cobalt and nickel from the organic phase to an aqueous phase with an eluting solution comprising water and/or sulfuric acid and/or metal sulfate, the aqueous phase being recycled to the extraction.

In certain embodiments of the second aspect, the method further comprises stripping at least some of any one or more of zinc, calcium, manganese and copper present in the organic phase obtained in step a) and other supported impurities having a higher affinity for the organic extractant than cobalt and nickel by: (a) Treating the organic phase with sulfuric acid by controlling the calcium concentration below its saturation level to avoid gypsum formation; or (b) if the calcium concentration in the system is relatively high and there is a risk of gypsum formation, treating the organic phase with hydrochloric acid.

In certain embodiments of the second aspect, the method further comprises periodically subjecting the organic phase to a precipitation (crystallization) treatment by contacting the organic phase in step a) with a hydrochloric acid solution (typically 6 moles HCl) to remove some of any one or more of iron, aluminum, and other strongly bound metal ions from the organic phase.

In certain embodiments of the second aspect, wherein step b) of selectively eluting the extracted nickel from the organic phase comprising purified cobalt is performed in a relatively high equilibrium pH range, preferably in an equilibrium pH range of 4.5-6.5, and selectively eluting the extracted magnesium from the organic phase comprising purified cobalt is performed in a relatively low equilibrium pH range, preferably in an equilibrium pH range of 3-5. The elution of nickel and magnesium may be performed sequentially in the higher pH range for nickel removal and then in the lower pH range for magnesium removal to obtain two separate eluents, or simultaneously in the lower pH range to remove both nickel and magnesium.

In certain embodiments of the second aspect, step b) further comprises co-extracting any magnesium present in the raffinate comprising purified cobalt and nickel into the organic phase. Magnesium may be separated from cobalt by: further eluting the co-extracted magnesium with sulfuric acid in a preferred equilibrium pH range of 3-5; and selectively re-extracting co-stripped cobalt from the magnesium-rich stripper into a portion of the organic phase, which portion may be recycled and incorporated into a major portion of the organic phase at the magnesium stripping point.

In certain embodiments of the second aspect, step b) purifies the organic phase by eluting both co-extracted nickel and magnesium from the organic phase comprising purified cobalt with sulfuric acid and/or an eluting solution of cobalt sulfate to obtain a nickel rich eluate, which may be recycled to the extraction step b) for recovery of nickel.

In certain embodiments of the second aspect, step b) further comprises extracting any magnesium present in the raffinate comprising purified nickel with a portion of the organic phase, and then eluting with sulfuric acid under conditions for removal of co-extracted nickel, which is recycled to extraction step b). The stripped organic phase is stripped with sulfuric acid to regenerate the organic phase and produce a magnesium-rich aqueous phase for further recovery of magnesium by-products.

In certain embodiments of the second aspect, the method further comprises preloading one or more organic solutions used in the method with a sulfate, carbonate, oxide salt, or hydroxide salt of nickel, cobalt, and/or magnesium. The method may include preloading one or more organic solutions used in the method with nickel sulfate. The method may further comprise treatment with an alkaline reagent (such as nickel hydroxide, sodium hydroxide or carbonate, ammonia, ammonium hydroxide or carbonate and magnesium oxide/hydroxide or carbonate) to neutralize or control pH during preloading. The method may further include pre-neutralizing the organic solution with an alkaline reagent to produce a pre-neutralized organic phase for preloading nickel by exchange. The alkaline agent may be selected from the group consisting of sodium hydroxide, sodium carbonate, ammonia, ammonium hydroxide or ammonium carbonate. The method may further comprise washing the organic solution preloaded with nickel sulphate with an elution solution comprising water and/or sulfuric acid and/or nickel sulphate to remove entrained and extracted sodium or ammonium ions.

In certain embodiments of the second aspect, the method further comprises directly neutralizing the acid produced during solvent extraction with ammonia, ammonium hydroxide, or ammonium carbonate under conditions to avoid formation of nickel ammonium double salts or ammonium sulfate salts, and subsequently thermally decomposing the ammonium component of the hydrated nickel sulfate.

In certain embodiments of the second aspect, the method comprises one or more stages in any extraction step, any elution step and any stripping step in solvent extraction and any loading step, any washing step and any elution step in ion exchange, which steps may be operated in countercurrent mode or in concurrent mode or in a combination of both modes.

In a third aspect, provided herein is a high purity nickel sulfate obtained by the method of the first aspect and/or the second aspect described above.

In a fourth aspect, provided herein is a high purity cobalt sulfate obtained by the process of the first and/or second aspects above, and optionally cobalt chloride, cobalt nitrate, if desired.

Drawings

Embodiments of the present invention will be discussed with reference to the accompanying drawings, in which:

FIG. 1 shows a schematic flow chart of an embodiment of the invention with respect to a scheme and method for treating MHP and/or PLS to produce a final feed solution, where the feed solution is substantially free of alkali metal ions (Na ⁺ And K ⁺ ) And monovalent cation species (NH) ₄ ⁺ ) Iron, aluminum and chromium and optionally removing a portion of the manganese.

FIG. 2 shows a schematic flow chart of an embodiment of the present invention with respect to a scheme and method for treating laterite nickel ore or nickel containing materials and solutions for producing iron and aluminum with alkali metal ions (Na ⁺ And K ⁺ ) And monovalent cation species (NH) ₄ ⁺ ) Has an optimal ratio of the total amount of MHP, which is advantageous for improving the treatment efficiency and the subsequent refining process shown in fig. 1, or alternatively for producing a catalyst containing almost no alkali metal ions (Na ⁺ And K ⁺ ) And monovalent cation species (NH) ₄ ⁺ ) And iron, aluminum and chromium and optionally removing a portion of the manganese feed solution or MHP.

FIG. 3 shows a flow chart of an embodiment of the present invention regarding a scheme and process for purifying a feed solution produced by the process shown in FIGS. 1 and 2 by SX and IX, the scheme and process characterized by (i) organic preload; (ii) SX for removing one or more impurities from the group of zinc, calcium, manganese, cadmium, copper, lead and any other impurities having a higher affinity for the organic extractant than cobalt and nickel; (iii) An SX loop for extracting both cobalt and magnesium from nickel, and then separating magnesium from cobalt within the SX loop; (iv) crystallizing nickel sulfate directly from the final SX raffinate; (v) Purifying the aqueous phase comprising purified cobalt from step (iii); and (vi) crystallizing cobalt sulfate or other cobalt salt from the aqueous phase comprising purified cobalt from step (v).

Fig. 4 shows a flow chart of an embodiment of the invention for purifying a feed solution produced by the process shown in fig. 1 and 2 by SX and IX, characterized by (i) direct neutralization with ammonia/ammonium hydroxide in SX, (ii) SX for removal of one or more impurities of the group of zinc, calcium, manganese, copper, cadmium, lead and any other impurities having a higher affinity for organic extractants than cobalt and nickel, (iii) one SX loop for extraction of both cobalt and magnesium from nickel and then separating magnesium from cobalt within the SX loop, (iv) direct crystallization of nickel sulfate from the final SX raffinate, (v) thermal decomposition of ammonium sulfate component in nickel sulfate hydrate to remove ammonium component as ammonia for recycling as alkaline reagent, (vi) purification of the aqueous phase from step (iii) comprising purified cobalt, and (vii) crystallization of cobalt sulfate or other cobalt salts from the aqueous phase from step (vi) comprising purified cobalt.

Fig. 5 shows a flow chart of an embodiment of the invention for purifying a feed solution produced by the process shown in fig. 1 and 2 by SX and IX, characterized by (i) organic pre-loading, (ii) SX for removing one or more impurities of the group of zinc, calcium, manganese, copper, cadmium, lead and any other impurities having a higher affinity for organic extractants than cobalt and nickel, (iii) two separate SX loops for separating cobalt from magnesium and then separating magnesium from nickel, (iv) direct crystallization of nickel sulfate from the final SX raffinate, (v) purification of an aqueous phase comprising purified cobalt from step (iii), and (vi) crystallization of cobalt sulfate or other cobalt salts from the aqueous phase comprising purified cobalt from step (v).

Fig. 6 shows a flow chart of an embodiment of the invention for purifying a feed solution produced by the process shown in fig. 1 and 2 by SX and IX, characterized by (i) direct neutralization with ammonia/ammonium hydroxide in SX, (ii) SX for removal of one or more impurities of the group of zinc, calcium, manganese, copper, cadmium, lead and any other impurities with higher affinity for organic extractants than cobalt and nickel, (iii) two separate SX loops for separating cobalt from magnesium and separating magnesium from nickel, (iv) direct crystallization of nickel sulfate in the final SX raffinate, (v) thermal decomposition of the ammonium sulfate component in nickel sulfate hydrate to remove the ammonium component as ammonia for recycle as alkaline reagent, (vi) purification of the aqueous phase comprising purified cobalt from step (iii), and (vii) crystallization of cobalt sulfate or other cobalt salts from the aqueous phase comprising purified cobalt from step (vi).

FIG. 7 compares air alone with SO ₂ Efficiency of the air mixture to convert Mn (II) to stable Mn (III/IV) oxide.

FIG. 8 shows nickel preload isotherms with 10% D2EHPA and 62g/L nickel (sulfate) solution at pH of about 5 and 50 ℃.

FIG. 9 shows isotherms of sodium elution from a preloaded 10% D2EHPA with 64.7g/L nickel (sulfate) solution at pH 3.6 and 50 ℃.

Fig. 10 shows the extraction profile isotherms with 10% D2EHPA of Ni pre-loaded at pH 3.1 and 40 ℃.

FIG. 11 shows extraction of Zn (II) and Cu (II) Ma Kaibu-Xi Letu (McCabe-Thielediagram) with Ni pre-loaded 10% D2EHPA at pH 3.1 and 40 ℃.

FIG. 12 shows extraction of Mn (II) and Ca (II) Ma Kaibu-Xi Letu with Ni pre-loaded 10% D2EHPA at pH 3.1 and 40 ℃.

FIG. 13 shows the use of 25% at 50℃and pH 6.8-7.0Nickel preload isotherms for 272 and 60g/L nickel (sulfate) solutions.

FIG. 14 shows the reaction from 25% preloaded at pH 5.5 and 50 ℃272, sodium eluting isotherm.

FIG. 15 shows the preloading of 25% Ni (II) at 40℃272 extract the distribution isotherms of Ni (II), co (II) and Mg (II).

FIG. 16 shows that Ni (II) is preloaded with 25% at 40 DEG C272 extract Ma Kaibu-Xi Letu of Co (II) and Mg (II).

FIG. 17 shows that at pH about 4.2 and pH about 5 and 40℃the load was 25%272, ma Kaibu-Xi Letu of nickel.

FIG. 18 shows that 25% of the load is removed at pH about 3.5 and pH about 4.2 and 40℃ 272, ma Kaibu-Xi Letu of magnesium is eluted. />

Detailed Description

For the purpose of teaching one of ordinary skill in the art to practice the invention, details of terms and methods are set forth below to provide a greater clarity regarding the compositions, methods, and uses thereof. The terminology used in the present invention is understood to be useful for the purpose of providing a better description of particular embodiments and is not to be taken in a limiting sense.

In the context of the present invention, when referring to measurable values such as amount, duration, etc., the term "about" is intended to encompass variations from the specified values of + -20%, + -10%, + -5%, + -1% or + -0.1%, as such variations are suitable for performing the disclosed methods.

In the context of the present invention, the terms "purified," "purity," and related terms are intended to mean a composition, compound, or material that has certain impurities or substances removed from a doped or contaminating substance. The term purified is a relative term and does not require absolute purity. Thus, for example, a purified compound is a compound in which the compound is more enriched than the compound in its natural environment or prior to any purification treatment.

In the present invention In this context, when used in reference to nickel or cobalt salts, the terms "high purity" and "battery grade" mean that the material has minimal levels of nickel or cobalt and/or low levels of trace elements such as Al, ca, cd, cr, cu, fe, mg, mn, na, pb, si and Zn, making them suitable for battery applications. For example, the "high purity" and/or "battery grade" nickel salts may have a nickel content of at least 21wt% (e.g., about 22wt% to about 23 wt%). For example, a nickel salt having a nickel content of 22.0wt%, 22.1wt%, 22.2wt%, 22.3wt%, 22.4wt%, 22.5wt%, 22.6wt%, 22.7wt%, 22.8wt%, 22.9wt% or 23.0wt% (e.g., nickel sulfate hexahydrate: niSO) ₄ ·6H ₂ O) is considered to be of high purity or battery grade. Similarly, the "high purity" and/or "battery grade" cobalt salts may have a cobalt content of at least 20wt% (e.g., at least 21wt% or, for example, about 20wt% to about 22 wt%). For example, a cobalt salt having a cobalt content of 20.0wt%, 20.1wt%, 20.2wt%, 20.3wt%, 20.4wt%, 20.5wt%, 20.6wt%, 20.7wt%, 20.8wt%, 20.9wt%, 21.0wt%, 21.1wt%, 21.2wt%, 21.3wt%, 21.4wt%, 21.5wt%, 21.6wt%, 21.7wt%, 21.8wt%, 21.9wt% or 22.0wt% (e.g., cobalt sulfate heptahydrate: coSO) ₄ ·7H ₂ O) is considered to be of high purity or battery grade.

In the context of the present invention, the term "soluble" is intended to mean capable of becoming molecularly or ionically dispersed in a solvent to form a homogeneous solution. Solubility can be determined by visual inspection, by turbidity measurement, or by dynamic light scattering.

Those of ordinary skill in the art will recognize that the definitions provided above are not intended to include impermissible combinations. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The singular terms "a" and "an" and "the" include plural referents unless the context clearly dictates otherwise. The term "include" means "include". Thus, the inclusion of "a" or "B" is meant to include a, include B, or include both a and B. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein. In case of conflict, the present specification, including an explanation of the terms, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

Generally described herein are processes by which high purity cobalt sulfate and high purity (battery grade) nickel sulfate can be produced from a crude raw material containing nickel and cobalt, such as Mixed Hydroxide Precipitate (MHP), without the need for costly nickel extraction steps by SX, thereby yielding economic advantages. The methods herein include one or more of the following steps:

a) Washing nickel/cobalt MHP or other nickel-containing materials to remove most or substantially all of the alkali metal ions (e.g., na ⁺ And K ⁺ ) And monovalent cation species (e.g., NH ₄ ⁺ ) And simultaneously partially removing other soluble impurities such as magnesium and calcium, and optionally converting divalent manganese ions to stable Mn (IV) oxides with an oxidizing agent while retaining nickel and cobalt as solid hydroxides;

b) The nickel and cobalt are redissolved, optionally followed by jarosite/alunite precipitation, if necessary, to remove residual alkali metal and monovalent cation species. This removal step may be performed simultaneously or sequentially;

c) Neutralizing the leach solution to precipitate remaining iron and aluminum as goethite, alumina, or hydroxide, and to precipitate chromium hydroxide and a portion of copper hydroxide, and optionally oxidizing the Mn (IV) oxide with an oxidizing agent to provide a feed solution;

d) Solid/liquid separation to obtain a nickel and cobalt enriched leach solution (PLS) containing nickel, cobalt, zinc, calcium, manganese (trace), copper, magnesium and being substantially free of alkali metal and monovalent cation species and iron, aluminum and chromium;

e) SX-based extraction and thus separation of zinc, manganese, copper and calcium and other impurities (e.g. cadmium, lead) having a higher affinity for organic extractants than cobalt and nickel from PLS using an organic phosphoric acid extractant (e.g. D2 EHPA), leaving PLS with cobalt, nickel and magnesium in the raffinate;

f) Using organic phosphinic acid extractants (e.g272 SX-based extraction of both cobalt and magnesium from PLS, either sequentially or simultaneously, leaving a nickel-rich PLS solution substantially free of impurities;

g) Separating the loaded magnesium from cobalt resulting from the simultaneous separation in step f) using a novel elution scheme within the SX loop;

h) Stripping cobalt from the purified cobalt-loaded organic phase with an acid to produce a stripping solution comprising purified cobalt, and regenerating the organic phase;

i) Purifying the stripping solution comprising purified cobalt by ion exchange (IX) to remove trace impurities such as copper and zinc and, if desired, by oxidative precipitation to remove trace manganese or by SX similar to step e) to remove various trace impurities such as zinc, manganese, copper and calcium, cadmium and lead;

j) Crystallizing high purity, battery grade cobalt sulfate or other cobalt salt from the purified cobalt loaded stripping solution (step i); and

k) The high purity, battery grade nickel sulfate is directly crystallized from the final SX raffinate (step f) described above, the purified nickel liquor.

The process herein provides a novel refining process and scheme to achieve an important economic value chain for unlocking nickel and/or cobalt containing raw materials such as laterite nickel deposits for producing high purity, battery grade nickel and cobalt sulfate products as lithium battery cathode precursor materials for the lithium battery industry.

Advantageously, the processes herein may be retrofitted to conventional and existing commercial processes for producing improved intermediates or solutions suitable for the subsequent refining processes herein. In addition, the methods herein offer great potential to expand existing operations or to justify investment in green land operations and to tamper with the nickel laterite industry.

In a first aspect of the invention, provided herein is a process for separating nickel and/or cobalt salts from nickel and/or cobalt containing crude material, the process comprising:

i. the iron is used for the production of the steel,

aluminum is used as a base material for the aluminum alloy,

chromium (Cr)

Copper.

Thus, the process of this first aspect comprises jarosite/alunite precipitation to remove alkali metal ions and monovalent cation species (figures 1 and 2).

Jarosite/alunite precipitation for deep removal of alkali metal ions (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) The species, jarosite/alunite precipitate, may be used alone or in successive steps after washing. The scheme of the treatment process herein includes washing only, jarosite/alunite only treatment and the optimal combination of washing and jarosite/alunite depending on the specific conditions associated with cost-effective factors (such as the content of alkali metal ions and monovalent cation species, water balance from the wash, efficient available solid/liquid separation facilities, iron and aluminum content in MHP and/or available iron and aluminum forms/sources suitable for jarosite/alunite precipitation).

Jarosite/alunite precipitation may be performed simultaneously with or sequentially after leaching. If desired, various forms of iron and aluminum may be added, preferably their sulfates or carbonates and oxides or hydroxides, to obtain the optimum ratio to alkali metal ions and monovalent cation species to achieve effective jarosite/alunite precipitation. An oxidizing agent may be present to oxidize iron (II) to iron (III), which oxidizing agent may also oxidize manganese (II) to stable manganese (IV) oxides.

Typical laterite nickel ores are rich in iron and aluminum, which partly enter PLS and are removed as hydroxides by neutralization prior to precipitation of MHP. If desired, a portion of the ferric hydroxide and aluminium hydroxide may be used as the iron source in the jarosite process.

In conventional processes, a known problem of precipitation of iron hydroxide and aluminum hydroxide is co-precipitation of nickel and cobalt, which becomes significant at higher pH for more complete removal of iron and aluminum to meet the standard specifications for MHP. To minimize the loss of nickel and cobalt in iron and aluminum hydroxide, staged precipitation of iron and aluminum and recycling of the final stage precipitate to leaching are typically employed, but the heavy recycle load will significantly reduce process efficiency and increase operating costs.

The presently disclosed methods not only provide a solution for processing intermediates (e.g., MHP), but they are also useful and beneficial for improving the overall laterite nickel ore process. According to the present method, no deep removal of iron and aluminum is required, since jarosite/alunite precipitation is required relative to alkali metal ions (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) The species are present in stoichiometric amounts of iron and aluminum species to remove these critical impurities. Thus, for subsequent jarosite/alunite precipitation, MHP may contain the desired ratio of iron/aluminum to the total amount of alkali metal and monovalent cation components.

Alternatively, the jarosite/alunite process is suitable for removing alkali metal ions (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) Species. The co-precipitation of nickel and cobalt in jarosite precipitates is known to be very low.

In the primary leaching process or in the refining process of MHP, the stoichiometric fraction of MHP relative to the total alkali metalIon of genus (Na) ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) The stoichiometric portion of the species may be used to neutralize the acid generated during jarosite/alunite precipitation, or in other words, the acid generated is used simultaneously to dissolve an equivalent amount of MHP without the need to add other alkaline reagents to avoid the introduction of impurities. In use, a portion of jarosite may be recycled and the solution crystallised at the appropriate dosage to improve the kinetics of jarosite precipitation.

Once jarosite precipitation is complete, the slurry pH is raised, preferably in stages, from a lower pH to a higher pH, to precipitate most of the remaining iron (III) in a good crystalline form, such as goethite, to minimize nickel and cobalt losses, and similarly, to precipitate the remaining aluminum in the form of alunite/alumina, rather than in the form of iron hydroxide and aluminum hydroxide. Alkaline agents, preferably nickel hydroxide, magnesium oxide/hydroxide, limestone/lime may be added for the neutralization process. The neutralization process will also remove chromium and a portion of the copper as hydroxides.

Optionally, the method of this first aspect may further comprise a washing step to remove alkali metal ions and monovalent cation species (fig. 1 and 2). Thus, the method may further comprise treating the nickel and/or cobalt containing raw material with an aqueous solution comprising water or dilute sulfuric acid under conditions for removing at least some of the one or more alkali metal ions and monovalent cation species prior to step a).

Although the wash of MHP may be included in conventional and existing refining processes, it is not intended to remove most or preferably substantially all of the alkali metal ions (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) Species are specifically designed.

Washing is the first step of the present process for treating MHP, wherein MHP is reslurried with a washing solution containing water and/or sulfuric acid to remove most or preferably substantially all alkali metal ions (Na ⁺ 、K ⁺ ) Monovalent cations (NH) ₄ ⁺ ) At the same time, the dissolution of nickel and cobalt is achievedMinimizing. The washing step may be performed at a pH of 7 or more. Multiple washes can be performed to achieve the desired degree of wash efficiency. The washing will simultaneously remove a substantial portion of other soluble materials such as calcium and magnesium as an additional benefit in facilitating subsequent purification by SX. Optionally, a portion or preferably a major portion of the Mn (II) is simultaneously converted to a stable solid Mn (IV) oxide with an oxidizing agent.

Optionally, the method of this first aspect may further comprise oxidatively converting the divalent Mn (II) form to a stable Mn (III/IV) form. Thus, the method may comprise treating the first nickel and/or cobalt containing material extract, the second nickel and/or cobalt containing material extract and/or the third nickel and/or cobalt containing material extract with an oxidizing agent under conditions for oxidizing any iron (II) to iron (III) and any manganese (II) to manganese (III/IV), thereby providing a mother liquor solution containing nickel and/or cobalt and having a reduced concentration of any one or more of alkali metal ions, monovalent cation species, iron, aluminum, chromium, copper and manganese relative to the nickel and/or cobalt containing crude material, wherein the mother liquor solution is suitable for further purification to produce high purity, battery grade nickel and/or cobalt salts.

During the above neutralization, a suitable oxidizing agent may optionally be added under controlled conditions, which is referred to as oxidative neutralization, to convert any iron (II) to iron (III) and, if desired, mn (II) to a stable Mn (III/IV) oxide. Early removal of a substantial portion of the manganese is preferred to facilitate subsequent purification by solvent extraction.

It is known that the losses of nickel and cobalt in solid forms such as jarosite/alunite, goethite and Mn (IV) oxide are minimized compared to amorphous ferric hydroxide and aluminium hydroxide. In addition, these forms of solid phase make liquid and solid separations by filtration or other separation means easier.

After the above treatment, the resulting feed solution is substantially free of alkali metal ions (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) Species, iron, aluminum and chromium, with partial removal of copper and manganeseThe feed solution contains the primary metals for further purification-nickel, cobalt, zinc, copper and manganese, calcium and magnesium remaining in the feed solution.

In a second aspect of the invention, disclosed herein is a method for obtaining purified nickel and cobalt from a feed solution produced according to the first aspect. The method comprises the following steps:

b) Contacting the aqueous raffinate with a cobalt selective extractant in a hydrocarbon diluent under solvent extraction conditions and separating the organic phase and the aqueous phase to produce an organic phase comprising purified cobalt and an aqueous phase comprising purified nickel;

c) Selectively eluting and stripping the organic phase to obtain an aqueous phase comprising purified cobalt;

d) Purifying the aqueous phase comprising purified cobalt to produce a further aqueous phase comprising purified cobalt;

e) Recovering cobalt from the further aqueous phase; and

f) Nickel is recovered from the aqueous phase comprising purified nickel.

In certain embodiments, the feed solution produced in the process of the first aspect is further purified by SX and IX to separate impurities from cobalt and cobalt from nickel, wherein the cobalt-rich liquor is further purified by ion exchange (IX) or SX to remove various trace impurities such as zinc and copper, thereby producing a purified cobalt liquor for crystallization of cobalt sulfate, while the primary metallic nickel in the final SX raffinate is fed directly to crystallization to produce high purity nickel sulfate. The purification method includes the following scheme.

Impurity SX (FIG. 3, FIG. 4, FIG. 5, FIG. 6)

The impurities zinc, calcium, manganese and copper, cadmium, lead and other impurities in the feed solution that have a higher affinity for the organic extractant than cobalt and nickel are extracted with hydrocarbon diluents such as Exxsol D80 and organophosphate (D2 EHPA) extractant in Escaid 110 and optionally in the presence of a phase modifier and separated from cobalt and nickel, leaving cobalt and nickel and part of the magnesium in the raffinate. There are options for stripping the organic phase loaded with impurities: (a) If the calcium concentration in the system is low, sulfuric acid is used to avoid gypsum formation by controlling the calcium concentration below its saturation level; and (b) hydrochloric acid if the calcium concentration in the system is relatively high and there is a risk of gypsum formation.

Separation of cobalt and magnesium (FIGS. 3, 4, 5, 6)

Organic phosphinic acids in hydrocarbon diluents such as Exxsol D80 and Escaid 110 (e.g272 or290 (and optionally in the presence of a phase modifier) may be used to separate cobalt, magnesium and nickel into the respective liquids. Two SX schemes may be used.

Co and Mg SX scheme option 1 (FIG. 3, FIG. 4): in certain embodiments, cobalt and magnesium are co-extracted and separated from nickel, and the loaded magnesium is separated from cobalt by an internal stripping scheme within the SX loop, wherein the co-extracted nickel is first stripped from the loaded organic phase to obtain a nickel-rich stripper that is recycled to the extraction, and then the extracted magnesium is stripped from the loaded organic phase to produce a magnesium-rich liquor containing some co-stripped cobalt, which is then extracted by a secondary stream in the organic solution and recycled to the main stripping section. This scheme allows the separation of the corresponding magnesium and cobalt streams from nickel in only one SX loop.

Co and Mg SX protocol option 2 (fig. 5, fig. 6): in certain other embodiments, cobalt is selectively extracted and co-extracted nickel and magnesium are stripped and recycled to the extraction and thus cobalt is separated from magnesium and nickel. The magnesium in the raffinate is then extracted and separated from the nickel in a separate solvent extraction circuit using a portion of the same organic solution.

Cobalt liquid purification and crystallization (FIG. 3, FIG. 4, FIG. 5, FIG. 6)

The cobalt loaded stripper is purified by ion exchange (IX) to remove trace impurities, such as copper with iminodiacetic acid resin and zinc with D2EHPA impregnating resin, or alternatively, both copper and zinc are removed simultaneously with aminophosphonic acid resin. By treatment with a suitable oxidising agent (e.g. ozone, SO in a ratio acting as oxidising agent ₂ /O ₂ The mixture of (air) or the oxidative precipitation of peroxomonosulphuric acid (caro's acid) and peroxodisulphuric acid selectively removes traces of manganese. Optionally, if desired, various trace impurities including zinc, copper, manganese, calcium, cadmium and lead can be removed from the cobalt-loaded stripper by SX with the above-described organophosphate (D2 EHPA) extractant. The purified cobalt liquor is fed to crystallization to produce high purity cobalt sulfate or other cobalt salts.

Direct crystallization of Nickel sulfate (FIGS. 3, 4, 5, 6)

The final raffinate, the purified nickel liquor, is fed directly into the crystallization to produce high purity nickel sulfate without the need for expensive nickel separation steps involving SX.

SX neutralization

During the SX process, organic phosphoric acid (e.g., D2 EHPA) and organic phosphinic acid (e.g.272 A stoichiometric amount of acid equivalent to the extracted divalent metal will be produced. It is therefore critical that the SX protocol be able to produce the final high purity nickel sulfate product without contamination. Two methods and schemes may be used.

Scheme 1-organic phase preloading (FIGS. 3 and 5)

Certain embodiments utilize nickel sulfate available within the above-described methods to directly preload the organic solution. Although other metal sulfates, or carbonates, or oxides/hydroxides may be used for the pre-load, such as cobalt sulfate and magnesium sulfate, or oxides/hydroxides thereof, nickel sulfate or nickel carbonate or nickel oxide/nickel hydroxide is preferred because any nickel introduced into the feed solution need not be further separated as compared to the cobalt or magnesium salt that needs to be separated again in the subsequent SX scheme. Neutralization or pH control may be performed in the preload using a suitable alkaline reagent such as nickel hydroxide, sodium hydroxide or carbonate, ammonia/ammonium hydroxide or carbonate and magnesium oxide/hydroxide or carbonate.

Alternatively, the stripped organic phase may be pre-neutralized with an alkaline reagent (such as sodium hydroxide or sodium carbonate, or ammonia/ammonium hydroxide or ammonium carbonate) to produce a pre-neutralized organic phase for preloading nickel by exchange.

The nickel preloaded organic solution is then washed with an stripping solution containing water and/or sulfuric acid and/or nickel sulfate to remove entrained and extracted sodium or ammonium ions, thereby avoiding contamination of the system. The eluted organic solution is then fed to the corresponding main SX loop to extract metal ions by exchanging the preloaded nickel with minimal or no pH control.

Scheme 2-direct neutralization and Heat treatment (FIGS. 4 and 6)

An alternative method employs direct neutralization of the acid produced during SX with ammonia/ammonium hydroxide under controlled conditions to avoid formation of nickel ammonium double salts or ammonium sulfate salts, and subsequent selective thermal decomposition of the ammonium component of the hydrated nickel sulfate, preferably in the form of ammonia that may be recycled as an alkaline reagent in the above-described process.

The present invention also provides a scheme for improving the overall upstream processing of laterite nickel ores or other nickel containing materials or solutions, including the following.

Upstream scheme 1: controlled neutralization of iron and aluminum precipitates to produce a precipitate containing iron and aluminum and alkali metal ions (Na ⁺ And K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) The desired ratio of species is used for MHP for subsequent jarosite/alunite precipitation in the refining process herein.

Upstream scheme 2: leaching and jarosite precipitation simultaneously or sequentially, thenNeutralization and solid/liquid separation are carried out to produce a solid/liquid mixture substantially free of alkali metal ions (Na ⁺ And K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) Feed solution of the species. This feed solution can be fed directly to the subsequent purification schemes herein by SX and IX, or to the production of MHP that is substantially free of alkali metal ions (Na ⁺ And K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) Species for subsequent leaching options as shown in fig. 1.

Further details of embodiments of the methods disclosed herein will now be described with reference to the accompanying drawings.

Scheme for treatment of MHP (FIG. 1)

The method and scheme described herein for treating various MHPs to produce a feed solution (126) suitable for subsequent purification processes to produce the corresponding high purity, battery grade cobalt and nickel sulfate is shown in fig. 1 without the need for costly major metal-nickel separation steps.

For removing alkali metal ions (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) The method of the species includes washing (105) and/or simultaneous leaching-jarosite/alunite (119) or leaching (112) and jarosite/alunite (115) in sequence. Washing (105) or jarosite/alunite (119, 112 and 115) may be used alone or in combination.

The steps of the processing scheme shown in (fig. 1) are described below.

Washing (105). Typical MHP from conventional and existing nickel laterite processes (101) or MHP (164, 191) resulting from the upstream nickel laterite process herein (fig. 2) are washed with a washing solution (104) of water or deionized or dilute sulfuric acid at a suitable liquid to solid ratio to remove a portion, preferably a major portion, and desirably the entire portion of alkali metal ions (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) Species (108). Other soluble components such as alkaline earth metals, ca (II) and Mg (II) can also be partially removed as well as nitrate ions and chloride ions. Washing may be performed in a variety of ways, including single or multiple timesReslurrying, flushing the filter cake and combinations of these means or continuous countercurrent decantation in multiple stages.

In the washing, an oxidizing agent (103) may be added to convert a portion, preferably a major portion, of the Mn (II) ions into stable solid Mn (IV) oxides. The oxidizing agent may be selected from, but is not limited to, air, oxygen, ozone, oxides, persulfuric acid, peroxides, peroxomonosulfuric acid (caro's acid), sulfur dioxide (SO) at the correct ratio ₂ ) An oxidizing mixture with air or oxygen. The addition of the oxidizing agent is controlled by monitoring the slurry potential and pH to minimize the oxidation of Co (II) and Ni (II) to Co (III) and Ni (III) oxides. Oxidizing agents with weak to moderate oxidizing power such as air, oxygen and their mixtures with sulfur dioxide in the correct ratio and caro's acid are preferred for continuous addition and easy control to minimize oxidation of Co (II) and Ni (II). The oxidation process is preferably carried out in the majority of MHP>95%) is carried out under undissolved conditions in the solid state to minimize the oxidation of Co (II) and Ni (II) to Co (III) and Ni (III) oxides in solid form.

The liquid and solids in the wash are separated (107) to produce washed MHP (109) with the desired washing efficiency of alkali metal ions and monovalent cation species and reduced levels of other soluble species such as Ca (II), mg (II), mn (II), and nitrate and chloride ions.

Leaching (112) and jarosite/alunite (115 and 119). In leaching, a quantitative sulfuric acid fraction at a clean stoichiometric ratio to the amount of MHP is added, or continuously, to dissolve the MHP. Depending on the alkali metal ion (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) The content of the species, jarosite/alunite precipitation (119) may be operated simultaneously with leaching (119) or sequentially after leaching (115). Jarosite/alunite is carried out according to the following reaction:

A ⁺ + 3M ³⁺ + 2SO ₄ ^2- + 6H ₂ O → AM ₃ (OH) ₆ (SO ₄ ) ₂ + 6H ⁺ (1)

wherein A is ⁺ Monovalent cation: na (Na) ⁺ 、K ⁺ 、NH ₄ ⁺ And M is ³⁺ ＝Fe ³⁺ 、Al ³⁺

According to reaction (1), in simultaneous or sequential leaching and jarosite/alunite treatment, an equal portion of MHP is added to neutralize the acid generated during jarosite/alunite precipitation (119) to control the desired pH range for jarosite/alunite precipitation (119) without the need to use other alkaline reagents that may introduce more impurities. In this way, the acid produced is used simultaneously for the dissolution of an equal portion of MHP.

According to reaction (1), if the contents of Fe (III) and Al (III) are relative to jarosite/alunite formation to completely remove monovalent cation species (Na ⁺ 、K ⁺ And NH ₄ ⁺ ) Is insufficient, various iron and aluminum forms, preferably Fe (III) and Al (III) hydroxides, oxides and sulfates, can be made of Fe (III)/Al (III) to Na equal to or higher than 3:1 ⁺ /K ⁺ /NH ₄ ⁺ Is added, preferably in a ratio in the range of 4:1 to 5:1.

Ferric hydroxide and aluminum hydroxide from conventional upstream precipitation processes are potential sources of iron and hydroxide. In FIG. 2 is shown a process for controlled Fe/Al precipitation to allow the presence of (Fe+Al) and (Na) in the feed solution and in the MHP ⁺ +K ⁺ +NH ₄ ⁺ ) Improved upstream processing of laterite nickel ore at the desired ratio of laterite nickel ore, as will be described later.

Jarosite precipitation may be operated at a temperature of 60 ℃ to 100 ℃ and a pH of 1.6 to 2.0, preferably in the range of 85 ℃ to 95 ℃ and a pH of 1.8 to 2.0, and at an oxidation-reduction potential (Eh) of the stable region of jarosite formation. Recycling a portion of jarosite as seed is preferred for promoting the kinetics of jarosite/alunite precipitation. If desired, an oxidizing agent may be added to oxidize any lower oxidation number iron species, such as Fe (II) to Fe (III).

After jarosite precipitation is complete, alunite precipitation may be carried out sequentially, preferably at a temperature in the range of 85 ℃ to 95 ℃ and at a pH in the range of 3.5 to 5.0, wherein the slurry pH is raised by neutralization (122), preferably in a staged manner (e.g. pH 2.5, pH 3.5 and pH 4 to 4.5), to precipitate the remaining iron (III) as goethite, oxide/hydroxide and aluminum as alunite and alumina/hydroxide, while chromium and a portion of copper will precipitate simultaneously as hydroxide. Depending on the specific requirements, there are several candidates for the alkaline agent (121) for neutralization (122), including nickel oxide/nickel hydroxide, magnesium oxide/magnesium hydroxide, limestone/lime, and fully washed MHP essentially free of alkali metal ions and monovalent cation species. An oxidizing agent (103) may optionally be present, which is referred to as "oxidative neutralization" (122) to oxidize Fe (II) to Fe (III) and/or to oxidize a majority of Mn (II) to solid Mn (III/IV) oxide.

The slurry (123) from the neutralization (122) is then transferred to a liquid and solid separation (124) to treat a residue (125) containing jarosite, alunite, goethite, hydroxides of Fe (III), al (III), cr (III) and Cu (II), and optionally manganese (III/IV) oxides, whereas the resulting feed solution (126) is substantially free of alkali metal ions (Na ⁺ 、K ⁺ ) And monovalent cations (NH) ₄ ⁺ ) Species as well as iron, aluminum, chromium, which contains nickel (in large amounts), cobalt, zinc, calcium, manganese (in small amounts) and partially reduced copper and magnesium, which feed solution is suitable for the subsequent purification processes herein, as shown in fig. 3, 4, 5 and 6.

Scheme for overall processing (FIG. 2)

The present invention provides not only a scheme for refining MHP intermediates from a conventional or existing laterite nickel process as shown in fig. 1, but also a scheme for upstream processing of laterite nickel ore or other nickel containing materials and solutions as shown in fig. 2 to directly produce a qualified feed solution suitable for the subsequent purification process (fig. 3, 4, 5 and 6), or alternatively to produce MHP (fig. 2) that is desirable for refining using the scheme herein as shown in fig. 1. The option of a scheme for the overall treatment of laterite nickel ore or nickel containing materials and solutions is as follows:

Scheme option 1-improved conventional process to produce alkali-free feed solution/MHP

In the prior art jarosite/alunite precipitation is used for removing or controlling iron and aluminium concentrations and/or for producing acids, wherein alkali metal salts (Na ₂ CO ₃ Or Na (or) ₂ SO ₄ ) Or ammonium salts such as (NH) ₄ ) ₂ SO ₄ . The method aims at removing alkali metal ions (Na) by jarosite/alunite precipitation ⁺ 、K ⁺ ) Or monovalent cations (NH) ₄ ⁺ ) Species in which a higher than stoichiometric amount of Fe is preferably required according to reaction (1) ³⁺ And Al ³⁺ 。

It is advantageous to use iron and aluminium components enriched in feed materials such as laterite nickel ores in leaching to remove these monovalent components early on by jarosite/alunite precipitation. The jarosite and alunite forms are easily separated by filtration or other liquid and solid separation techniques. It is known that the losses of nickel and cobalt caused by precipitation with jarosite and alunite are very small. Scheme option 1 includes the steps of:

leaching with conventional leaching methods such as High Pressure Acid Leaching (HPAL) and Atmospheric Leaching (AL) may be performed in one step (156) simultaneously with jarosite/alunite precipitation or in successive steps of leaching (152) and jarosite/alunite (154) under the conditions described above for step (115) (fig. 1).

The slurry (155 or 157) is neutralized (158) with an alkaline reagent (121), the remaining iron is removed as goethite/hydroxide and the remaining aluminum is removed as aluminum oxide/hydroxide, and other metal hydroxides such as chromium hydroxide and copper hydroxide are removed. An oxidizing agent (103) may optionally be added to oxidize any Fe (II) to Fe (III) and Mn (II) to a stable solid Mn (IV) oxide under the conditions described above for the neutralization step (122) (fig. 1).

The slurry (159) from the neutralization (158) is subjected to a solid/liquid separation (160) to obtain a slurry substantially free of monovalent cations (Na) ⁺ 、K ⁺ 、NH ₄ ⁺ ) Feed of iron, aluminium and chromiumA feed solution (162), and treating a residue (161) containing jarosite/alunite, goethite, alumina and hydroxides of iron, aluminum, chromium and copper, and Mn (III/IV) oxides.

If desired, the feed solution (162) may be fed to a subsequent purification scheme as shown in fig. 3, 4, 5 and 6. Depending on the concentration of nickel and/or cobalt, the feed solution (162) may be concentrated by means of water separation (e.g., by membrane distillation) and then fed to a subsequent purification scheme as shown in fig. 3, 4, 5 and 6.

Alternatively, the feed solution (162) is subjected to mixed hydroxide precipitation (163) to produce MHP (164), which is then leached in step (112) (fig. 1) to produce feed solution (126) for further purification using the schemes shown in fig. 3, 4, 5 and 6 to produce high purity, battery grade nickel sulfate and cobalt sulfate.

Scheme option 2-improved conventional method to produce MHP with desired Fe/Al to Na/K ratio

In conventional nickel laterite processes, one challenging problem is the loss of nickel and cobalt caused by adsorption/precipitation with ferric hydroxide and aluminum hydroxide precipitates. To minimize losses, iron and aluminum precipitation is typically operated in multiple stages, with the last stage ferric hydroxide and aluminum hydroxide precipitate being recycled to leaching, which significantly reduces process efficiency and increases process costs.

As described above, the MHP feed flow diagram shown in fig. 1 allows iron and aluminum to be present in the desired ratio of alkali metal ions and monovalent cation species required for subsequent jarosite/alunite precipitation. Thus, there is no need for deep removal of iron and aluminum by primary neutralization, and recycling of the final stage ferric hydroxide and aluminum hydroxide precipitate practiced in conventional processes can be reduced or eliminated. The main steps of scheme option 2 and the principles for controlling iron and aluminum content in MHP are as follows.

After leaching (152) and solid/liquid separation (181), the PLS (183) is neutralized with an alkaline reagent such as limestone or lime (185) toPrecipitating iron and aluminum (184) under controlled conditions such that portions of Fe (III) and Al (III) in PLS are precipitated relative to monovalent cations (Na ⁺ +K ⁺ +NH ₄ ⁺ ) Preferably in the range of (3-6): 1 and more preferably (4-5): 1, based on their ratio measurement in MHP (191).

After liquid and solid separation (187) of the slurry (186), the residue (188) is treated and PLS (189) is fed to the mixed hydroxide precipitate (190) by adding an alkaline reagent such as magnesium oxide/magnesium hydroxide (14) to produce MHP (191) with [ Fe (III) +al (III) desired for jarosite/alunite precipitate (115 or 119)]And (Na) ⁺ +K ⁺ +NH ₄ ⁺ ) To remove monovalent cations (Na) ⁺ +K ⁺ +NH ₄ ⁺ )。

Solvent extraction of impurities (typically Zn (II), mn (II), cu (II) and Ca (II)) (FIGS. 3, 4, 5 and 6)

The impurities Zn (II), mn (II), cu (II) and Ca (II), cd (II), pb (II) in the feed solution (126, 162) and other impurities having a higher affinity to the organic extractant than cobalt and nickel are extracted with an organic phosphoric acid, such as di (2-ethylhexyl) phosphoric acid (D2 EHPA). The SX scheme comprises the following steps:

The stripped organic phase (211) is preloaded (212) with nickel sulfate (126 or 162, or 221 or 331) shown in fig. 3 and nickel sulfate (419 or 503) shown in fig. 5 using an alkaline reagent (213) such as sodium hydroxide or sodium carbonate or ammonia/ammonium hydroxide to produce a preloaded nickel organic phase (216) and sodium sulfate or ammonium sulfate byproduct (215). Alternatively, the stripped organic phase may be pre-neutralized (222) with an alkaline reagent (213) such as sodium hydroxide or sodium carbonate or ammonia/ammonium hydroxide to produce a pre-neutralized organic phase (223) for preloading (212) nickel by exchange.

The preloaded organic phase (216) is eluted (217) with an eluting solution (218) containing water and/or dilute sulfuric acid and/or nickel sulfate to remove extracted and entrained sodium or ammonium ions to an eluting solution (219) that is recycled to the preload (212).

The eluted/preloaded organic phase (220) is fed to impurity extraction (201), wherein the impurities Zn (II), mn (II), cu (II) and Ca (II), cd (II), pb (II) in the feed solution (126 or 162) and other impurities having a higher affinity for the organic extractant than cobalt and nickel are extracted into the organic phase by exchanging the preloaded nickel into the aqueous phase. Minimal pH control with sulfuric acid can optionally be employed to maintain the desired pH profile for the multiple extraction stages, if desired.

The loaded organic phase (202) is eluted (203) with an eluting solution (205) of water and/or sulfuric acid and/or metal sulfate to remove the extracted nickel and cobalt to an eluting solution (204), which is recycled to the extraction (201).

The stripped organic phase (206) is stripped (207) with a stripping solution (208) of sulfuric acid or hydrochloric acid (HCl) to regenerate an organic phase (211) for feeding to a pre-load (212) or optionally to a pre-neutralization (222).

Selection of acid (H) for stripping (207) ₂ SO ₄ Or HCl) (208) depends on the concentration of calcium. If the calcium concentration is significantly below its gypsum-forming saturation level, sulfuric acid for stripping under controlled conditions to avoid gypsum formation is preferred due to the same sulfate matrix. If the calcium concentration is high, hydrochloric acid may be used to avoid gypsum formation. If hydrochloric acid is used, a washing stage may be required to remove chloride ions entrained in the organic phase before transferring the stripped organic phase (211) for preloading (212) or preneutralization (222).

The stripping solution (210) containing impurities, typically Zn (II), mn (II), cu (II) and Ca (II), may be further treated to separate and recover the specific metals of interest. For example, zinc can be separated from other impurities by selective stripping to produce individual byproducts, if desired.

It will be appreciated that trace amounts of iron and aluminum, as well as other higher ions, will be strongly extracted by D2EHPA and that periodic precipitation of the organic phase with 6M HCl may be required, depending on load and capacity requirements.

Extraction of cobalt and magnesium in an SX Loop with preloaded organic phases (FIG. 3)

The present invention provides the use of an organic phosphinic acid, such as bis (2, 4-trimethylpentyl) phosphinic acid in a hydrocarbon diluent and optionally in the presence of an organic phase modifier272 or->290 A) to extract both cobalt and magnesium from the raffinate (221) (301) and separate the magnesium from the cobalt in the loop. The scheme comprises the following steps:

the stripped organic phase (324) is preloaded (325) with nickel sulfate (221 or 331) available in the process using an alkaline agent (213) for neutralization, such as ammonium hydroxide or ammonium carbonate or sodium hydroxide, to produce a nickel preloaded organic phase (326) and an ammonium sulfate or sodium sulfate byproduct (215). Alternatively, the stripped organic phase (324) may be pre-neutralized (332) with an alkaline reagent (213) such as sodium hydroxide or sodium carbonate or ammonium hydroxide to produce a pre-neutralized organic phase (333) for preloading (325) nickel by exchange.

The preloaded organic phase (326) is eluted (327) with an eluting solution (328) of water and/or sulfuric acid and/or nickel sulfate to remove extracted and entrained sodium and ammonium ions from the organic phase into an eluting solution (329) that is recycled to the preload (325).

Both cobalt and magnesium in the raffinate (221) are extracted (301) with an eluted/preloaded organic phase (330) and separated from nickel remaining in the raffinate (331).

The loaded organic phase (302) is first eluted (303) with an eluting solution (304) of water and/or sulfuric acid and/or cobalt sulfate to selectively remove the extracted nickel in the organic phase to an eluting solution (305) that is recycled to the Co/Mg extraction (301).

The nickel stripped organic phase (306) is further stripped (307) with a stripping solution (308) of water and/or sulfuric acid and/or cobalt sulfate solution to remove extracted magnesium from the organic phase, thereby obtaining a magnesium rich stripping solution (309) with some co-stripped cobalt.

The co-stripped cobalt in the magnesium-rich eluent (309) is then extracted (310) with a small portion of the stripped organic phase (321), where an alkaline reagent (311) such as ammonia/ammonium hydroxide or sodium carbonate can be used directly for neutralization, if desired. Alternatively, the stripped organic phase (321) may be treated with magnesium sulfate (MgSO ₄ ) Is preloaded (334) with an alkaline agent (311) for pH adjustment, preferably magnesium oxide/magnesium hydroxide and/or ammonia/ammonium hydroxide, or sodium hydroxide or sodium carbonate, and then fed for cobalt extraction (310) by exchange of the preloaded base metal.

The entrained or extracted ammonium or sodium in the organic phase in steps (334 and 310) above may be removed from the organic phase by an stripping step (314) to an stripping solution (316), which is recycled to the extraction (310).

The magnesium-rich raffinate (312) may be further processed to produce magnesium sulfate or magnesium oxide or magnesium hydroxide for recycle as a base (311) for pre-loading and neutralization in the process.

The secondary stream in the cobalt loaded organic phase (317) is combined with the primary stream in the nickel stripped organic phase (306) as a feed (318) for the stripping (307) of magnesium.

The magnesium stripped organic phase (319) is stripped (320) with a sulfuric acid stripping solution (323) to obtain a cobalt loaded stripping solution (322) and the organic phases (321 and 324) are regenerated, which are recycled to the preloads (325 or 334). If desired, the cobalt may be stripped with other acids such as hydrochloric acid and nitric acid, respectively, for producing other salt products, wherein a washing step may be required before and after stripping to avoid cross-contamination by organic phase inversion.

The cobalt loaded stripping solution (322) containing trace amounts of zinc and copper may be prepared by using an iminodiacetic acid resin such asTP 207 IX to remove copper, then leached with D2EHPAThe stain resin is->VP OC 1026 is purified by zinc IX (601). Alternatively, aminophosphonic acid chelate resins such as +.>S950 may potentially be used to remove both copper and zinc.

If desired, it is known that the polymers can be prepared by chelating resins such as bis-picolmethylaminesM4195 separates nickel from cobalt.

Trace amounts of manganese may also be present in the cobalt loaded stripping solution (322) and oxidants such as ozone, SO at ratios that act as oxidants may be utilized ₂ /O ₂ (air) mixtures, peroxomonosulphate (caro's acid) and peroxodisulphate selectively precipitate traces of manganese as Mn (III/IV) oxide.

The purified cobalt liquor (603) is fed to cobalt crystallization (604) to produce high purity, battery grade hydrated cobalt sulfate (605).

Raffinate (331) from Co/Mg SX (301) was fed directly to crystallization (701) to produce high purity, battery grade hydrated nickel sulfate (702).

Optionally, if desired, the cobalt loaded stripper (322) may be purified by SX with an organic phosphoric acid (D2 EHPA) extractant as described above to remove various trace impurities such as zinc, copper, calcium, manganese, cadmium, lead, and other impurities.

Extraction of cobalt and magnesium in a SX loop by direct neutralization (FIG. 4)

Instead of pre-loading as shown in fig. 3, an alternative SX scheme (fig. 4) uses direct neutralization of the acids generated during SX processes (201) and (301) with ammonia/ammonium hydroxide (222).

The main SX scheme for separating impurities, typically Zn (II), mn (II), cu (II) and Ca (II), and then extracting cobalt and magnesium (301) using D2EHPA (201) is the same as the SX scheme shown in fig. 3. The ratio (a/O) of aqueous to organic phase is selected and controlled to avoid the formation of nickel ammonium sulphate double salts during the SX process.

The ammonium sulfate produced in neutralization (201 and 301) will eventually be present in the SX raffinate (331) along with the nickel. Part of the ammonium sulfate will crystallize with the hydrated nickel sulfate (703) into a nickel ammonium sulfate double salt.

The thermal decomposition step (704 or 706) is designed to convert the double salt of sulfuric acid to nickel sulfate (708), wherein the ammonium sulfate can be decomposed into ammonia, sulfur trioxide and nitrogen-containing gas (705) at a temperature above 280 ℃. It is preferred to selectively decompose only the ammonium component into ammonia (222) for recycling as an alkaline reagent, for which purpose an oxide/hydroxide such as nickel oxide/nickel hydroxide (707) may be added to form nickel sulfate (708). Nitrate, nitrite and nitrous acid components, if present, will be at least partially removed in this step.

Extraction of cobalt and magnesium with preloaded organic phases by separate SX loop (fig. 5)

The present invention provides an alternative SX scheme to extract cobalt from magnesium and nickel first, and then using the same272 extract magnesium from nickel as shown in fig. 5. The SX scheme for removing impurities (typically Zn (II), mn (II), cu (II) and Ca (II)) with D2EHPA is the same as the SX scheme described above and shown in fig. 3.

An alternative SX scheme for extraction and separation of cobalt and magnesium by means of separate SX loops comprises the following steps:

will be stripped272 (410 and 511) is preloaded (411) with nickel sulphate (419 or 503) available in the process, which in case of alkaline reagents (213) such as sodium hydroxide or sodium carbonate, or ammonia/ammonium hydroxide, yields a nickel loaded organic phase (413) and ammonium sulphate or sodium sulphate by-product (215). Alternatively, the stripped organic phases (410 and 511) may be treated with an alkaline reagent (213)) Pre-neutralization (420) to produce a pre-neutralized organic phase (421) for pre-loading (411) nickel by exchange.

The preloaded organic phase (413) is eluted (414) with an eluting solution (415) of water and/or sulfuric acid and/or nickel sulfate to remove extracted and entrained sodium or ammonium ions from the organic phase into an eluting solution (416) which is recycled to the preload (411).

Cobalt in the raffinate (221) from impurity SX (201) is extracted (401) by exchange with a portion of the eluted/preloaded organic phase (418) and separated from magnesium and nickel in the raffinate (419).

The cobalt loaded organic phase (402) is eluted (403) with an eluting solution (404) comprising water and/or sulfuric acid and/or cobalt sulfate to remove the extracted nickel and magnesium into an eluting solution (405) which is recycled to the cobalt extraction (401).

The nickel and magnesium stripped organic phase (406) is stripped (407) with a sulfuric acid stripping solution (408) to regenerate the organic phase (410), which is recycled to the preload (411).

The cobalt loaded stripping solution (409) containing trace amounts of zinc and copper was purified by IX (601) as described above. If desired, traces of nickel can be removed by IX (601) using bis-picolylamine chelating resin and traces of manganese can be removed by oxidation with an oxidizing agent such as Carronic acid.

Optionally, if desired, the cobalt loaded stripper (409) may be purified (601) by SX with an organic phosphoric acid (D2 EHPA) extractant as described above to remove various trace impurities such as zinc, copper, calcium, manganese, cadmium, lead and other impurities.

Magnesium in the cobalt extraction raffinate (419) is extracted (501) with a portion of the preloaded organic phase (502).

The magnesium loaded organic phase (504) is eluted (505) with an eluting solution (506) comprising water and/or sulfuric acid to remove the extracted nickel into an eluting solution (507) which is recycled to the magnesium extraction (501).

The stripped organic phase (508) is stripped (509) with a stripping solution of sulfuric acid (510) to obtain a magnesium loaded stripping solution (512) and the organic phase (511) is regenerated, which is recycled to the preload (411).

The magnesium loaded stripping solution (512) containing magnesium sulfate (513) may be crystallized to produce magnesium sulfate byproduct, or the magnesium loaded stripping solution may be further processed to produce MgO/Mg (OH) that may be used as an alkaline reagent in the process ₂ Byproducts.

The nickel containing raffinate (503) from the magnesium solvent extraction (501) is fed directly to nickel crystallization (701) to produce high purity, battery grade hydrated nickel sulfate (702).

Extraction of cobalt and magnesium by direct neutralization through a separate SX loop (fig. 6)

Instead of the pre-load method and scheme as shown in (fig. 5), the present invention provides an alternative method and scheme (fig. 6) for direct neutralization of the acids generated during SX processes (201), (401) and (501) using ammonia/ammonium hydroxide (222). The ratio (a/O) of aqueous to organic phase is selected and controlled to avoid the formation of nickel ammonium sulphate double salts during the SX process.

The main SX scheme for separating impurities (Zn (II), mn (II), cu (II), and Ca (II)) with D2EHPA (201) and using two separate SX loops to separate cobalt (401) and magnesium (501) is the same as the SX scheme shown in fig. 5.

Ammonium sulphate resulting from neutralization of acids in the SX process (201, 401 and 501) is eventually present in the final SX raffinate (503) along with nickel. Part of the ammonium sulfate will crystallize with the nickel sulfate (703) as a nickel ammonium sulfate double salt.

Examples

EXAMPLE 1 washing MHP

Wet MHP (4.2 kg,48.9% moisture) was reslurried with deionized water at 40 ℃ for 30 minutes with continuous stirring, and then filtered through a pressure filter. This repulping/filtering procedure was repeated for multiple washes. The conditions and results are given in table 5.

The sodium and potassium content in the feed MHP decreases with washing, with a corresponding increase in the Ni/Na and Ni/K ratios.

After three washes, the ratio of Ni/Na and Ni/K increased from 142 to 3929 and 378 to 3522, respectively, corresponding to 25ppm Na normalized to 100g/L Ni and less than 28ppm K in the feed solution if the washed MHP was completely dissolved.

After six washes, the ratio of Ni/Na and Ni/K increased from 142 to 26281 and 378 to 12533, respectively, corresponding to less than 10ppm Na and less than 20ppm K in the nickel sulfate product assuming all Na and K entered the final nickel sulfate product containing 22.3% Ni.

Thus, in principle, the sodium and potassium content of MHP can be removed to very low levels by washing and high efficiency filtration (e.g. pressure filtration) to meet the requirements and specifications of the final nickel sulphate product. However, this does not limit the cost-effective combination of washing and jarosite/alunite precipitation methods in the examples below.

The magnesium and calcium content of MHP is also significantly reduced by washing, which will facilitate the subsequent purification process.

TABLE 5 washing of MHP

EXAMPLE 2 jarosite precipitation and neutralization

This example presents jarosite precipitation using a feed having the composition shown in table 6. The feed was heated to 95 ℃ with stirring and aeration, while 20 g of jarosite seed crystals produced from previous jarosite precipitation were added. By adding the washed MHP as obtained in example 1, the slurry pH was adjusted and kept in the pH range of 1.8-2.0. At 7.3 hours, the slurry was filtered by vacuum using a horse Xie Li-Nagel (Macherey-Nagel) MN615 filter paper. The composition of the final solution and washed solids is given in table 6.

Sodium in solution was reduced from 118mg/L to 3.1mg/L feed, corresponding to 99.8% Na precipitation efficiency and Ni/Na ratio rising from 770 to 31119. The nickel and cobalt in jarosite precipitate were measured to be 0.03% and 0.07%, respectively.

This example shows that sodium ions can be deeply removed to very low levels by jarosite precipitation, which meets the requirements and specifications of a feed solution suitable for subsequent purification by SX and IX to produce high purity, battery grade nickel sulfate.

TABLE 6 jarosite precipitation

After jarosite precipitation as described above, lime was dosed to raise the slurry pH in stages: pH 2.1 (95 ℃), pH 2.4 (62 ℃), pH 3.6 (62 ℃) and pH 4.4 (62 ℃) while allowing the slurry temperature to drop from 95 ℃ to 62 ℃ after 80 minutes. The test conditions and results are given in table 7.

At pH 4.4 (62 ℃ C.), the remaining iron and aluminum in the solution drops below 1mg/L, while the final washed solids in jarosite and neutralization co-precipitate about 0.04% and about 0.08% total nickel and cobalt, respectively.

TABLE 7 neutralization

Example 3 oxidative conversion of Mn (II) to Mn (IV) oxide

This example shows the use of air and SO ₂ The MHP (44.46% Ni,4.6% Co,0.88% by weight of the air mixture) Mn) into a stable solid Mn (IV) oxide. MHP is reslurried in deionized water at 29% (dry solids) slurry density and 60 ℃. Continuously blowing air or in the range of 0.5-1% (v/v) SO ₂ Sulfur dioxide (SO) ₂ ) And air, the slurry is continuously stirred.

Slurry samples were collected periodically and vacuum filtered through a horse Xie Li-nagel MN615 filter paper. The solid cake from the filtration was leached with 1M sulfuric acid solution and then the insoluble leaching residue sample was completely dissolved in 6M HCl solution. The concentrations of nickel, cobalt and manganese in the leachate samples were determined by ICP-AES/MS, on the basis of which the conversion efficiencies of manganese and precipitated nickel and cobalt were calculated. In FIG. 7, the blowing of air alone and the blowing of SO were compared ₂ Conversion results in the case of an air mixture.

In the case of air alone, the conversion rate was initially fast but declined over time, with a conversion of about 60% at 60 minutes. In alternative air and SO ₂ In the case of the air mixture, the conversion increased almost linearly, with conversion efficiency at 170 minutes>97%, corresponding to Mn in the leaching solution relative to 100g/L Ni if MHP is dissolved <0.1g/L。

Further analysis of the data shows that the kinetic behavior of conversion with air alone can be approximated by a second order rate reaction with respect to the soluble Mn (II) content, however with SO ₂ The kinetic behavior of the conversion at air mixtures is characteristic of zero-order rate kinetics, i.e. independent of Mn (II) content. In application, the conversion can be carried out with the initial bubbling of air only, to obtain a rapid conversion of the majority of Mn (II), followed by bubbling of SO ₂ Air gas mixture to achieve a more complete conversion.

In principle, complete conversion of Mn (II) can be achieved if desired. In this process, complete conversion of Mn (II) is optional, as the remaining Mn (II) at lower levels can be removed by subsequent SX schemes using D2 EHPA.

In the case of air alone for 90 minutes, at the endThe precipitated cobalt and nickel in the solid residue were 0.88% and 0.08%, respectively, and were alternatively in use with SO ₂ In the case of an air mixture and air lasting 300 minutes, it was 3.37% and 0.09%, respectively. Thus, the parameters used for the conversion (e.g., pH, flow rate, SO ₂ Air (O) ₂ ) Ratio and residence time) can be optimized for the desired Mn (II) conversion efficiency with minimal nickel and cobalt conversion.

Example 4-Nickel Pre-load of D2EHPA

The preload profile isotherms shown in this example were established with a feed solution of 10% D2ehpa and 62.6g/L Ni (sulfate) in Exxsol D80 at 50 ℃ and about pH 5 with sodium hydroxide for neutralization and pH control. The results are shown in fig. 8. Ma Kaibu-Schiff diagrams show that there are two to three theoretical stages of nickel extraction at an operating A/O ratio of 1:10 (FIG. 8).

EXAMPLE 5 elution of preloaded D2EHPA

This example shows that entrained and loaded sodium from sodium hydroxide in the pre-load as an alkaline reagent for neutralization can be eluted from the loaded organic phase.

The elution profile isotherms shown in this example were performed at 50 ℃ and about pH 3.6 using 10% D2EHPA and 64.8g/L Ni (sulfate) elution solution in Exxsol D80 preloaded with nickel. The elution results are shown in fig. 9.

The Ma Kaibu-schlempe graph constructed based on the data shows that there are two to three theoretical stages of sodium eluting the load at an operating a/O ratio of about 1:10. The elution of nickel is reasonably in the range of 10% -15% with nickel being recycled to the pre-load section in continuous operation. Elution conditions with respect to composition of the eluting solution, eluting pH, a/O ratio and stage may be further optimized. In a continuous SX process with multiple stages, an optimal pH profile may be applied.

Example 6 extraction of impurities with preloaded D2EHPA

This example presents an extraction profile isotherm for extracting impurities (Zn (II), cu (II), mn (II) and Ca (II)) with 10% (v/v) D2EHPA of preloaded nickel (6.3 g/L) in Exxsol D80. Each portion of the nickel preloaded organic phase was contacted with a corresponding portion of synthetic PLS (g/L: 93.1Ni, 9.23Co, 2.80Mg, 3.2Zn, 0.08Mn, 0.034Ca and 0.087 Cu) separately for 10 minutes with continuous mechanical agitation at various A/O ratios, pH of about 3.1 and 40 ℃.

The metal distribution isotherms are shown in fig. 10. The negative extraction efficiency of nickel indicates that the metal impurities are extracted by displacement of the preloaded nickel. The Ma Kaibu-schiller diagrams shown in fig. 11 and 12 demonstrate three theoretical extraction stages for extracting and separating impurities (Zn (II), mn (II), cu (II) and Ca (II)) from nickel and cobalt with 10% D2EHPA at an operating a/O ratio of 1.5.

Example 7- (2 nd)272 nickel preload

This example shows that 25% of Exxsol D80 is preloaded with 56g/L Ni (sulfate) at 50℃and pH 6.8-7.0 using sodium hydroxide for neutralization and pH control272. The distribution isotherms and Ma Kaibu-Xi Letu for nickel preload are shown in FIG. 13, which predicts two to three theoretical stages of nickel extraction at an operating A/O ratio of 1:4.

Example 8 from preloaded272 sodium is eluted

This example demonstrates a pre-loaded 25% from Exxsol D80 at pH 5.5 for an elution solution using 65g/L Ni (sulfate)272 removes the elution profile isotherms of the entrained and extracted sodium. The metal distribution isotherms and Ma Kaibu-Xi Letu constructed based on the data are shown in fig. 14, which shows that there are two to three theoretical stages of sodium elution with reasonable nickel elution at an operating a/O ratio of 1:15,the nickel elution can be further minimized in a multi-stage operation with an optimal pH profile. In continuous operation, the eluent may be recycled to the pre-load section for nickel recovery.

EXAMPLE 9 use272 extraction of cobalt and magnesium

As shown in fig. 3, the present invention provides an SX scheme for extracting both cobalt and magnesium and then separating the loaded magnesium from the cobalt by an elution scheme within the SX loop. This example presents a method for using 25% (v/v)272 (14.44 g/L Ni) organic solution preloaded with nickel in Exxsol D80 and synthetic solution containing (g/L) 103Ni, 11.4Co and 3.2Mg extract cobalt and magnesium from nickel and separate it from nickel.

The test results are shown in fig. 15. The negative extraction efficiency of nickel indicates that the preloaded nickel is exchanged by extraction of cobalt and magnesium. Ma Kaibu-Schiff diagram prediction, 25% can be used at 0.6:1 operation A/O 272 extract both cobalt and magnesium in two to three (theoretical) extraction stages (fig. 16).

Example 10 elution of Nickel and magnesium from a Supported organic phase

These examples show 25% (v/v) from Exxsol D80 preloaded at 6.477g/L Co, 1.632g/L Ni and 1.722g/L Mg272, and then eluting the loaded magnesium at a lower pH range. Elution profile isotherms at pH 5, pH 4.2 and pH 3.5 are shown in fig. 17 and 18, respectively.

The distribution isotherm and Ma Kaibu-schierle plot indicate that for nickel eluting the load in the pH range of 4.2-5, the concentration of nickel is 25% 272 have one to two theoretical extraction stages at an operation a/O of 1:7 (fig. 17). The nickel rich eluate is recycled to the extraction stage in a continuous operation.

The distribution isotherm and Ma Kaibu-schierle plot demonstrate three to four elution stages of magnesium eluting the load over a pH range of 3.5-4.2 and an operating a/O ratio range of 1:4-1:9 (fig. 18), which can be further optimized for magnesium elution efficiency in continuous operation and for selectivity versus cobalt in multi-stage operation using the optimal pH profile.

Some of the salient features and advantages of the methods herein are summarized below:

1) To produce high purity, battery grade nickel and cobalt sulfate, conventional and existing refining processes require costly SX-based extraction and subsequent stripping of the primary metals, nickel, from the relatively small amounts of impurities present (typically at an impurity/nickel ratio of <1/15 in the original MHP) using organic carboxylic acids such as Versatic 10. In addition, two additional SX phases are required. The present invention avoids the most costly nickel SX step, so that only two SX steps are required, thereby reducing capital and operating costs.

2) The present invention provides a method that enables simple separation of alkali metal and monovalent cation species.

3) The present invention provides a novel SX scheme for extracting and separating the corresponding cobalt and magnesium from nickel in one SX loop or in two separate SX loops. Both schemes for separating magnesium from nickel are new and the former performed in one SX loop provides the lowest SX requirements and thus the lowest capital and operating costs.

4) The present invention provides two methods and schemes for neutralization of acids generated during SX: (a) The organic phase is preloaded with nickel sulfate available in the process to avoid contamination of the system from alkaline reagents, or (b) is directly neutralized with ammonia/ammonium hydroxide, which is then removed from the final hydrated nickel sulfate by thermal decomposition, preferably thermally decomposed into ammonia for recycling as alkaline reagents in the process.

5) The present invention provides an oxidative precipitation process for converting soluble divalent manganese ions Mn (II) to stable solid Mn (III/IV) oxides with minimal loss of nickel and cobalt in the wash stage and/or for facilitating early removal of simple separated manganese in subsequent purification by SX in a subsequent oxidative neutralization step.

6) The iron and aluminum content enriched in laterite nickel ores is conventionally leached and the final stage precipitates are removed as hydroxides by neutralization with substantial recovery to minimize nickel and cobalt losses that significantly reduce process efficiency and increase processing costs.

7) The present invention provides a method and scheme for improving the overall process efficiency of nickel laterite treatment, the method and scheme comprising:

(a) Controlled neutralization for precipitation of iron hydroxide and aluminum hydroxide to achieve iron and aluminum with alkali metal ions (Na ⁺ And K ⁺ ) And monovalent cations (e.g., NH) ₄ ⁺ ) The desired ratio of species to remove these monovalent cations and species in jarosite/alunite form, so that conventional upstream removal and bulk recovery of product MHP through Cheng Zhongtie and aluminum is not required; and

(b) Removal of alkali metal ions (Na ⁺ And K ⁺ ) And monovalent cations (e.g., NH) ₄ ⁺ ) Jarosite/alunite of the species precipitates to produce a feed solution or MHP that is substantially free of these monovalent cations and species and can be fed to the simplified refining and purification processes that follow herein.

The present invention relates to a refining process for producing high purity, battery grade nickel sulfate and cobalt sulfate products from a wide range of feed materials including, but not limited to:

● Intermediate products containing nickel and cobalt such as MHP;

● Laterite nickel ore or other nickel and cobalt containing materials;

● A solution containing nickel and cobalt;

● Used battery material;

● Manganese marine nodule; and

● Waste materials and tailings containing nickel and cobalt.

It should be understood that the terms "comprises" and "comprising," as well as any derivatives thereof, such as include, etc. as used in this specification and the following claims, are to be construed as including the features to which the term refers, and are not intended to exclude the presence of any additional features, unless otherwise indicated or implied.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge.

In some instances, a single embodiment may combine multiple features for brevity and/or to aid in the understanding of the scope of the invention. It should be appreciated that in such cases, these multiple features may be provided separately (in separate embodiments) or in any other suitable combination. Alternatively, where separate embodiments describe separate features, these separate features may be combined into a single embodiment unless otherwise indicated or implied. This also applies to claims that can be recombined in any combination. That is, the claims may be modified to include the features defined in any of the other claims. Further, a phrase referring to "at least one" of a series of items refers to any combination of those items, including individual members. As an example, "at least one of a, b, or c" is intended to encompass: a. b, c, a-b, a-c, b-c and a-b-c.

Those skilled in the art will appreciate that the use of the present invention is not limited to one or more of the specific applications described. The present invention is also not limited in its preferred embodiments with respect to the specific elements and/or features described or depicted herein. It should be understood that the invention is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions without departing from the scope set forth and defined by the following claims.

Reference to the literature

Selective leaching of nickel and cobalt from the mixed hydroxide intermediate involves forming a mixed hydroxide intermediate slurry, treating the hydroxide intermediate slurry with an oxidizing agent, and leaching the oxidized slurry in an acidic sulfate medium (Selective leaching of nickel and cobalt from mixed hydroxide intermediate involves forming mixed hydroxide intermediate slurry, treating hydroxide intermediate slurry with oxidizing agent, and leaching oxidized slurry in acid sulfate medium); AU 2016256773-A1.

Fittock, J.E.,1992. Refining of nickel and cobalt by Kunsland Nickel industry, kunsland, inc. (Nickel and cobalt refining at QNIPty Ltd Yabulu Queensland), australian mining and metallurgical society, monograph 19 (AUSIMM 19), pages 1-47.

Preparation of high purity cobalt intermediate compounds-from cobalt sulfate solutions, in the case of formation of tetramine complexes using solvent extraction (prepn.of high purity cobalt intermediate cpds. — from cobalt sulphate sons.using solvent extraction with formation of a tetramine complex). Patent No. EP 651062-A1; AU 9477522-A; CA 2134490-A; ZA 9408497-a; AU 670398-B; AU 9667964-A; US 5605668-a; AU 677559-B; EP 651062-B1; DE 69415633-E; ES 2126071-T3; US 6048506-a; CA 2134490-C.

Price, m.j. and Reid, j.g.,1987. Separation of nickel and cobalt in an ammonia-type system-stripping from the organic phase with aqueous ammonia carbonate (sepn.of nickel and cobalt in ammoniacal systems-by organic extraction of nickel and stripping from the organic phase with aq. Ammonia ammonium carbonate sol.). Patent No. WO 8809389-a; AU 8816454-A; EP 364463-A; BR 8807511-A; JP 2503575-W; US 5174812-a; EP 364463-A4; CA 1335332-C; EP 364463-B1; DE 3854499-G; JP 96009741-B2.

The hydrometallurgical leaching of nickel comprises combining nickel sulphide ore with nickel laterite and grinding to form a slurry, leaching the combined slurry in a pressure acid leaching circuit, and providing an oxidising agent to the pressure acid leaching circuit (Hydrometallurgical leaching for nickel comprises combining nickel sulfide ore with nickel laterite and milling to form slurry, leaching combined slurry in pressure acid leach circuit, and providing oxidant to pressure acid leach circuit); AU 2008100563-B4.

A hydrometallurgical process for leaching nickel from nickel ore compositions involves feeding sulphide ore to an autoclave comprising a high pressure acid leaching circuit for laterite nickel feed materials (Hydrometallurgical method for leaching nickel from nickel ore composition, involves adding sulfide ore to autoclave of high-pressure acid leach circuit including nickel laterite feed material, and adding oxidant to autoclave) and oxidant to the autoclave; AU 2008101213-B4; AU 2008101213-A8; AU 2008101213-B8.

Nickel recovery from laterite ores using oxime extractants-by acid leaching, precipitation of nickel hydroxide, re-leaching with aqueous ammonia, extraction with water-immiscible hydrocarbons containing water-insoluble oximes, acid stripping and electrowinning (Nickel recovery from laterite ore using oxime extractant-by acid leaching, precipitating nickel hydroxide, re-leaching with aqueous ammonia, extracting with water-insoluble oxime in water-immiscible hydrocarbon, acid stripping and electrowinning). Patent No. WO 9743023-A1; AU 9730543-A; EP 915727-A1; US 5976218-a; AU 727561-B; CA 2252592-C.

Claims

1. A process for separating nickel and/or cobalt salts from a nickel and/or cobalt containing crude material, the process comprising:

i. the iron is used for the production of the steel,

aluminum is used as a base material for the aluminum alloy,

chromium (Cr)

Copper.

2. The method of claim 1, further comprising treating the nickel and/or cobalt containing raw material with an aqueous solution comprising water and/or sulfuric acid under conditions for removing at least some of the one or more alkali metal ions and/or monovalent cation species prior to step a).

3. The process of claim 1 or claim 2, further comprising treating the feed solution obtained from step b) with an oxidant under conditions for oxidizing any iron (II) to iron (III) and any manganese (II) to manganese (III/IV) in a higher oxidation state.

4. A process according to any one of claims 1 to 3, wherein the iron or aluminium salt in step a) is selected from the group consisting of sulphate, carbonate, oxide and hydroxide salts.

5. A process for obtaining purified nickel and cobalt from the feed solution obtained according to any one of claims 1 to 4, the process comprising

a) Reducing the concentration of any zinc, calcium, manganese, copper, cadmium, lead or other metallic impurities having a higher affinity for the organic extractant than cobalt and nickel in the feed solution by contacting the feed solution with an organic phosphoric acid extractant in a hydrocarbon diluent under solvent extraction conditions, and separating the organic and aqueous phases to produce an aqueous raffinate comprising purified cobalt and nickel;

e) Recovering cobalt from the further aqueous phase; and

f) Recovering nickel from the aqueous phase comprising purified nickel.

6. The method of claim 5, wherein step b) comprises:

a) (i) co-extracting both cobalt and magnesium in the aqueous raffinate from step a) into the organic phase; (ii) Selectively eluting any co-extracted nickel from said organic phase with an eluting solution of sulfuric acid and/or cobalt sulfate at a relatively high equilibrium pH range to obtain a nickel-depleted said organic phase and a nickel-rich eluent (aqueous phase), which is recycled to step (i); (iii) Further eluting magnesium selectively from the organic phase with an eluting solution of sulfuric acid and/or cobalt sulfate at a relatively low equilibrium pH range to obtain the organic phase with purified cobalt and a magnesium rich eluting solution (aqueous phase); (iv) Re-extracting any co-stripped cobalt in the magnesium-rich stripper (aqueous phase) with a small portion of the organic phase to obtain a small portion of a cobalt-loaded organic phase that is incorporated into a major portion of the organic phase in step (iii); and (v) stripping the organic phase from step (iii) to produce an aqueous phase comprising purified cobalt; or (b)

b) (i) selectively extracting cobalt in the aqueous raffinate from step a) into the organic phase; (ii) Eluting both co-extracted nickel and magnesium in the organic phase with an eluting solution of sulfuric acid and/or cobalt sulfate to obtain the organic phase with purified cobalt and a nickel and magnesium rich eluting solution (aqueous phase), which is recycled to step (i); (iii) Stripping cobalt from the purified organic phase from step (ii) with an acid to obtain an aqueous phase (stripping solution) comprising purified cobalt; (iv) Selectively extracting the magnesium from the step (i) raffinate with a portion of the organic solution to obtain an aqueous phase comprising purified nickel (final raffinate) and a magnesium-rich organic phase; (v) Eluting any co-extracted nickel in the organic phase with an elution solution of sulfuric acid to obtain an elution solution (aqueous phase) comprising purified nickel, said elution solution being recycled to step (iv); and (vi) stripping the magnesium-rich organic phase to obtain an aqueous phase comprising purified magnesium for recovery of magnesium by-products.

7. The process of any one of claims 5 or 6, wherein the organophosphate extractant is of formula (RO) ₂ PO ₂ H, wherein each R group, which can be the same or different, is selected from optionally substituted branched, straight or cyclic alkyl, alkenyl or alkynyl groups.

8. The process of claim 7, wherein the organic phosphoric acid is di-2-ethylhexyl phosphoric acid or an organic phosphoric acid having similar or identical extraction characteristics to those of di-2-ethylhexyl phosphoric acid.

9. The process of any one of claims 5 to 8, wherein the cobalt selective extractant is of formula R ₂ PO ₂ The organic phosphinic acids of H, wherein each R group, which can be the same or different, is selected from optionally substituted branched, straight or cyclic alkyl, alkenyl or alkynyl groups.

10. The process of claim 9, wherein the organic phosphinic acid is di-2, 4-trimethylamyl phosphinic acid (bis (2, 4-trimethylamyl) phosphinic acid) or an organic phosphinic acid having extraction characteristics similar to or the same as the extraction characteristics of di-2, 4-trimethylamyl phosphinic acid.

11. The method according to any one of claims 5 to 10, wherein the hydrocarbon diluent is an aliphatic or aromatic hydrocarbon solvent or a mixture thereof.

12. The method of claim 11, wherein the hydrocarbon diluent is kerosene.

13. The process according to any one of claims 6 to 12, wherein step a) and/or step b) is performed in the presence of a phase modifier or a combination of phase modifiers in any hydrocarbon diluent present in the hydrocarbon diluent.

14. The method of claim 13, wherein the phase modifier is selected from one or more of the group consisting of isodecanol, isotridecanol, 2-ethylhexanol, and tri-n-butyl phosphate.

15. The method according to any one of claims 5 to 14, wherein step c) of purifying the aqueous phase comprising purified cobalt comprises removing at least some of any copper from the aqueous phase comprising purified cobalt.

16. The method of claim 15, wherein the step of removing at least some of any copper from the aqueous phase comprising purified cobalt comprises contacting the aqueous phase comprising purified cobalt with iminodiacetic acid resin under conditions for binding with copper, and separating copper-loaded resin from the aqueous phase.

17. The process of any one of claims 5 to 16, wherein the step c) of purifying the aqueous phase comprising purified cobalt comprises removing at least some of any zinc from the aqueous phase comprising purified cobalt.

18. The method of claim 17, wherein the step of removing at least some of any zinc from the aqueous phase comprising purified cobalt comprises contacting the organic phase comprising purified cobalt with D2 EHPA-impregnated resin under conditions for binding with zinc and separating zinc-loaded resin from the aqueous phase.

19. The process of any one of claims 5 to 18, wherein said step c) of purifying said aqueous phase comprising purified cobalt comprises removing at least some of any manganese from said aqueous phase comprising purified cobalt.

20. The method of claim 19, wherein the step of removing at least some of any manganese from the aqueous phase comprising purified cobalt comprises contacting the aqueous phase comprising purified cobalt with an oxidant under conditions for oxidizing any manganese (II) to a higher oxidation state manganese (III/IV), and separating the manganese (III/IV) from the aqueous phase.

21. The method of claim 20, wherein the oxidant is selected from the group consisting of oxygen (air), ozone, SO at a ratio that acts as an oxidant ₂ /O ₂ (air) mixtures, peroxomonosulphuric acid (Caro's acid) and peroxodisulphuric acid.

22. The process of any one of claims 5 to 21, wherein the step c) of purifying the aqueous phase comprising purified cobalt comprises removing one or more of zinc, calcium, manganese, copper, cadmium, lead or other metallic impurities in the aqueous phase comprising purified cobalt by contacting the aqueous phase comprising purified cobalt with an organophosphate extractant in a hydrocarbon diluent under solvent extraction conditions, and separating the organic phase and the aqueous phase to produce a further aqueous phase comprising purified cobalt.

23. The method of claim 22, wherein the organophosphate extractant is of formula (RO) ₂ PO ₂ H, wherein each R group, which can be the same or different, is selected from optionally substituted branched, straight or cyclic alkyl, alkenyl or alkynyl groups.

24. The method of claim 23, wherein the organic phosphoric acid is di-2-ethylhexyl phosphoric acid or an organic phosphoric acid having similar or identical extraction characteristics to those of di-2-ethylhexyl phosphoric acid.

25. The process of any one of claims 5 to 24, wherein the step of recovering cobalt from the aqueous phase comprising purified cobalt comprises crystallizing cobalt sulfate from the aqueous phase comprising purified cobalt.

26. The method of any one of claims 5 to 25, wherein the step of recovering nickel from the aqueous phase comprising purified nickel comprises crystallizing nickel sulfate from the aqueous phase comprising purified nickel.

27. The process of any one of claims 5 to 26, further comprising stripping at least some of any one or more of zinc, calcium, manganese and copper present in the organic phase obtained in step a) by: (a) Treating the organic phase with sulfuric acid by controlling the calcium concentration below its saturation level to avoid gypsum formation; or (b) if the calcium concentration in the system is relatively high and there is a risk of gypsum formation, treating the organic phase with hydrochloric acid.

28. The method of claim 27, further comprising periodically subjecting the organic phase to a precipitation (crystallization) process by contacting the organic phase in step a) with a hydrochloric acid solution to remove some of any one or more of iron, aluminum, and other strongly bound metal ions from the organic phase.

29. The method of any one of claims 5 to 28, further comprising preloading one or more organic solutions used in the method with sulfate, carbonate, oxide or hydroxide salts of nickel, cobalt and/or magnesium.

30. The method of claim 29, comprising preloading one or more organic solutions used in the method with nickel sulfate.

31. The method of any one of claims 29 to 30, further comprising treating with an alkaline reagent selected from the group consisting of nickel hydroxide, sodium hydroxide or sodium carbonate, ammonia, ammonium hydroxide or ammonium carbonate, and magnesium oxide/hydroxide or magnesium carbonate to neutralize or pH control in the pre-load.

32. The method of any one of claims 29 to 30, comprising pre-neutralizing the organic solution with an alkaline reagent to produce a pre-neutralized organic phase for pre-loading nickel by exchange.

33. The method of claim 32, wherein the alkaline reagent is selected from the group consisting of sodium hydroxide or sodium carbonate, ammonia, and ammonium hydroxide or ammonium carbonate.

34. The method of any one of claims 30 to 33, further comprising washing the organic solution preloaded with nickel sulfate with an elution solution comprising water and/or sulfuric acid and/or nickel sulfate to remove entrained and extracted sodium or ammonium ions.

35. The method of any one of claims 5 to 34, further comprising directly neutralizing an acid generated during solvent exchange with ammonia, ammonium hydroxide, or ammonium carbonate under conditions to avoid formation of nickel ammonium double salts, and subsequently thermally decomposing an ammonium sulfate component in the hydrated nickel sulfate to remove the ammonium component.

36. The method of any one of claims 5 to 35, wherein any extraction step, any elution step and any stripping step in solvent extraction and any loading step, any washing step and any elution step in ion exchange comprise one or more stages operated in countercurrent mode or concurrent mode or a combination of the two modes.

37. A high purity nickel sulphate obtained using the method according to any one of claims 5 to 36.

38. A high purity cobalt sulphate obtained using the method according to any one of claims 5 to 36.