FR2717826A1 - Process for the extraction and separation of nickel and / or cobalt. - Google Patents

Abstract

The present invention also aims to provide a separation of nickel from cobalt by charging them, selectively, in an organic phase compatible with one or more of one of the preceding objects. The present invention therefore relates to a hydrometallurgical process intended for the recovery of metals in which is obtained, more particularly, an aqueous filler solution originating from an acid leaching and containing nickel and / or cobalt ions. The pH of the solution is maintained in a range between approximately 2 and 6. The aqueous loading solution is brought into contact with an organic phase, immiscible in water, which contains an extraction solvent in order to charge it with ions. nickel and / or cobalt metals so as to obtain an organic phase containing metals.

Description

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  The present invention relates to a process for the extraction and separation of nickel and / or cobalt.

  This invention is in the field of hydrometallurgy. It relates more particularly to the recovery and the separation of nickel and / or cobalt using a liquid-liquid extraction from aqueous solutions derived from the acid leaching of ores. In the solvent extraction processes of the prior art, organic phases consisting of an organic extraction solvent, an organic diluent and, optionally, soluble organic compounds, usually referred to as "phase modifiers ", are brought into contact with an aqueous phase charged with metals of interest in a counter-current technique, with transverse currents or else with parallel currents during one or more of a step. The organic phase is chosen in such a way that it is not miscible with the aqueous phase. The hydrogen ions from the organic phase are exchanged with the metal ions from the aqueous phase so that the organic phase becomes charged with metals of interest while the aqueous phase floats depleted in metals of interest. The pH of the aqueous phase is usually controlled to maintain the yield and to adjust the selectivity to metals of the exchange technique. After extraction, the organic phase loaded with metals is brought into contact with an acid in a counter-current, cross-flow or parallel-flow technique during one or more stages in order to transfer the metals of interest to the aqueous solution. The interesting metals from this

  aqueous solution can then be recovered by various means, for example, by electrolytic extraction.

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  Efficient recovery of nickel and cobalt from acid leaching solutions, such as those from the leaching of laterite ores is known to be possible by precipitation using hydrogen sulfide. When precipitation with hydrogen sulfide is carried out, the resulting precipitate based on mixed nickel / cobalt sulfide can be further refined by treatments which may optionally incorporate solvent extraction. Advantageously, the extraction by solvent is carried out directly on the leaching solution in order to eliminate the stage of precipitation of the sulphides. This direct solvent extraction route eliminates the costs associated with the difficult production and handling of hydrogen sulfide gas and has the potential advantage of directly preparing products on the market. Direct solvent extraction processes have been applied on an industrial scale for many years to recover copper. With respect to cobalt and nickel, solvent extraction has been limited almost exclusively to the refining of nickel-cobalt-based intermediate products (Bautista, R., "The Solvent Extraction of Nickel, Cobalt and their Associated Metals ", Extractive Metallurgy of Copper, Nickel and Cobalt, vol. I; Fundamental Aspects, R. Reddy and R. Weizenbach (Editeurs), The Minerals, Metals, and Materials Society, 1993, pp. 827-852). The only exception is for the direct recovery30 of nickel / cobalt from ammoniacal leaching liquors, as described, for example, in US Patents 3,907,966 and 3,981,968. Attempts to adapt extraction solvents intended for recovery of nickel and cobalt from solutions obtained, which come from

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  Direct acid leaching of ores or concentrates, using, for example, sulfuric acid have been, to a large extent, unsuccessful. A main reason is that these solutions typically contain significant amounts of manganese, magnesium and / or calcium, in the dissolved state and these metals are often extracted together with nickel and cobalt. For example, extraction solvents based on carboxylic or organophosphorous acid make it possible to extract cobalt and nickel but also also, in parallel, often even preferentially, manganese (and to a lesser extent calcium and magnesium). The co-extraction of these metal ions leads to the loss of a significant part of the carrying capacity of the extraction solvent and does not allow obtaining liquors of

  pure washing. This possibly makes the extraction solvent unacceptable on an industrial scale. In addition, excess aqueous solubility is typically a problem for extraction solvents, such as carboxylic acids.

  Extraction solvents which comprise a mixture of carboxylic acids and non-chelating oximes have demonstrated a selectivity for nickel and cobalt, greater than that for manganese, magnesium and calcium. However, non-chelating oximes usually have high aqueous solubilities and tend to be hydrolyzed. Extraction solvents based on chelating hydroxyoximes such as ketoximes and salicylic aldoximes, most of them having been developed on an industrial scale, for the extraction of copper (II) from leaching solutions with sulfuric acid, have also demonstrated selectivity for nickel and cobalt (II) over manganese, calcium and magnesium. However, a

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  when loaded into these chelating oximes, cobalt (II) tends to oxidize cobalt (III), which adversely affects washing and can degrade the oxime-type reagent. In addition, the rate of nickel extraction, using extraction solvents based on chelating oximes, has been reported to be very low (Szymanowski, J. Hydroxyoximes and Copper Hydrometallurgy, CRC Press, 1993, p. 281 ). Mixtures of chelating hydroxyoximes with di-nonyl naphthalene sulfonic acid (DNNS) have demonstrated an improved extraction of nickel, DNNS accelerates the degradation of oxime (Oliver, AJ and Ettel, VA, "LIX 65N and Dowfax 2A0 Interaction in Copper Solent Extraction and Electrolysis ", CIM 14th Annual Conf.,

Edmonton, August 1975, pp. 383-88).

  Brown et al., In US Patent No. 4,721,605 describes a process by which the metals selected from the group consisting of zinc, silver, cadmium, mercury, nickel, cobalt and copper, can be separated from calcium and / or magnesium, which are present in an aqueous solution by means of solvent extraction using dithiophosphinic acids. In addition, B.T. Tait reports in "Cobalt-Nickel Separation: The Extraction of Cobalt (II) and Nickel (II) by Cyanex 301.25 Cyanex 302 and Cyanex 272", Hydrometallurgy, 32 (1993) pp. 365-372, that the extracting agent called Cyanex 301 (Cyanex is a trademark to characterize the organophosphorous extraction solvents distributed by Cytec Canada Inc.) extracts both nickel and cobalt and can also be used to selectively remove cobalt from a solution containing nickel. However, the difference in the pH values for which 50% of the cobalt and 50% of the nickel are extracted, is a relatively small value35 of only 1.1 units. In this article, Tait note

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  also the drawback of the requirement of a strong acid to remove cobalt when using an extraction solvent of the Cyanex 301 type. Tait also suggests in "The Extraction of Some Base Metal Ions by Cyanex5 301, Cyanex 302 and Binary Extractant Mixtures with Aliquat 336 ", Solv. Extr. Ion Exch., 10 (5) (1992), pp. 799-809, that manganese is also extracted by Cyanex 301 for higher pH values than for nickel and cobalt. Sole et al. in "Solvent10 Extraction Characteristics of Thiosubstituted Organophosphinic Acid Extractants", Hydrometallurgy, 30 (1992) pp. 345-65, demonstrates that there is practically no separation between nickel and cobalt when using Cyanex 301. Unlike Tait, Sole et al. 15 indicated that Cyanex 301 has a slight preference for nickel over cobalt. In addition, Cote and Bauer described in "Metal Complexes with Organothiophosphorus Ligands and Extraction Phenomena," Reviews in Inorganic Chemistry, Vol. 10, N 1-3, (1989) 20 pp. 121-144, that the class of extraction solvents based on organothiophosphorous acids can be oxidized to disulfides by trivalent iron present in the solution as well as by trivalent cobalt which can form in the organic phase as a result of oxidation of bivalent cobalt by atmospheric oxygen. Cote and Bauer further noted that the oxidation of cobalt

  bivalent to trivalent cobalt can be avoided in the presence of oxygen-donating reagents in the organic phase, such as tri-octylphosphine oxide (TOPO), tri-butyl phosphate (TBP) or octanol (ROH).

  None of the foregoing references describes an industrially viable process for the selective recovery of metals, such as nickel and / or cobalt, rather than metals such as manganese, calcium and magnesium in solutions.

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  acids. Acid leaching from nickel-forming laterite ores, for example, produces leaching solutions containing nickel and cobalt, often combined with significant amounts of impurities, such as manganese and magnesium. Accordingly, an interesting contribution to this technique would be a process for the selective extraction by solvent, only of nickel and cobalt from aqueous solutions which contain these metals as well as manganese, magnesium and the like. After the main separation of nickel and cobalt from other metals using solvent extraction, additional extraction solvents are often required for the separation of nickel from cobalt. A single extraction solvent15 capable of separating nickel and cobalt from other metals and of separating nickel from cobalt, would further contribute to developing the field of recovery of nickel and cobalt. The subject of the present invention is a process for the selective recovery of metallic nickel and / or cobalt from acidic aqueous solutions in

  using solvent extraction and avoiding the co-extraction of other metals present in the same solution, such as, without limitation, manganese, calcium and magnesium.

  The present invention also aims to provide a simple and economical method, compatible with the preceding object. The present invention also aims to provide a

  organic phase exhausted, reusable, compatible with one or two of the preceding objects.

  The object of the present invention is further to provide a separation of nickel from cobalt by means of selective exhaustion from an organic phase.

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  charged, separation that is compatible with one or more of the foregoing goals. The present invention also aims to provide a separation of nickel from cobalt by charging them, selectively, in an organic phase compatible with one or more of one of the preceding objects. The present invention therefore relates to a hydrometallurgical process intended for the recovery of metals in which is obtained, more particularly, an aqueous filler solution originating from an acid leaching. The aqueous filler solution contains nickel and / or cobalt ions. The pH of the solution is maintained in a range between approximately 2 and 6. The aqueous loading solution is brought into contact with an organic phase, immiscible in water, which contains an extraction solvent in order to charge it with ions. nickel and / or cobalt metals so as to obtain an organic phase containing metals. The extraction solvent is at least one dithiophosphinic soluble organic acid or one of its alkali, alkaline-earth or ammonium salts. The aqueous filler solution has sufficiently low levels of chromium (VI) ions, ferric ions and copper ions to allow repeated use of the extraction solvent. The organic phase containing the metals is then separated from the aqueous filler solution containing metals. Finally after separation of the aqueous filler solution, the organic phase containing metals is brought into contact with an aqueous depletion solution in order to recover the charged nickel and / or cobalt originating from the organic phase containing the

  metals. The invention will be better understood using the following description of its embodiments

favorite.

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  It has been discovered that organic extraction solvents of the dithiophosphine type can be used effectively to separate nickel and / or cobalt from acid leaching solutions while maintaining chromium (VI), iron (III) ions. and copper at rates that allow repeated use of the extraction solvent. It has also been discovered that the nickel / cobalt separation is achieved by extracting nickel and cobalt together with an organic extraction solvent of the dithiophosphine type, and then selectively depleting the cobalt co-charged with the solvent. organic extraction of the dithiophosphine type with a dilute acid solution, soluble in water, while the nickel is depleted, subsequently, with a more concentrated solution of the same or a different acid, soluble in water. It has also been discovered that the nickel / cobalt separation can be carried out, as a variant, by selectively loading only the nickel onto an organic extraction solvent of dithiophosphine type, essentially leaving the cobalt in the aqueous refined product and in then extracting this cobalt with the same or another extraction solvent, by treatment in a separate circuit. After the preferential charge, the nickel and the cobalt are exhausted with solutions of the same type of water-soluble acid or of a different type, from an organic extraction solvent (s) ( s) .30 It has also been discovered that organic extraction solvents of the dithiophosphine type can be used to effectively separate, by solvent extraction, nickel and / or cobalt from manganese (II), which is present in acid leaching solutions of oxide ores. The solvent

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  of dithiophosphine type organic extraction easily combines with nickel ions and cobalt ions in the organic phase leaving the manganese ions in the aqueous refined product. The process of the invention uses an extraction solvent of dithiophosphine type for separating nickel and / or cobalt from acid leaching solutions. Examples of suitable ores for acid leaching include oxide ores, sulfide ores and manganese or marine nodules which contain nickel and / or cobalt. Most advantageously, the method of the invention is used to treat laterite ores. The leaching solution should be kept at a pH between about 2 and 6 before loading the nickel and / or cobalt ions on the extraction solvent. Advantageously, the leaching solution is maintained at a pH between about 3 and 6 before charging. Most advantageously, the leach solution is maintained at a pH between about 3 and 5.5 before loading. Advantageously, the leaching solution is partially neutralized in order to remove the free acid before the extraction step. Removal of free acid during partial neutralization minimizes or even eliminates the need for base addition during subsequent solvent extraction operations. During partial neutralization, the majority of the iron (III), chromium (III), aluminum and copper ions precipitate, leaving a majority of nickel and cobalt ions in the solution. After precipitation, the ions are easily separated from the aqueous filler solution in a solid / liquid separation step. In some cases, it may be desirable to oxidize ferrous ions to ferric ions before the partial neutralization step. So

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  advantageous, the ferrous ions are oxidized to ferric ions by contact with an oxygen-containing gas. In some cases, when manganese (IV) ions are present in the leach solution, these manganese (IV) ions are also precipitated during partial neutralization. The

  partial neutralization can be achieved using an appropriate basic reagent. Most advantageously, the pH of the leach solution is adjusted by means of calcium carbonate.

  Advantageously, after removal of the ferric ions, the remaining ferric ions are reduced to ferrous ions in order to avoid unwanted degradation of the extraction solvent. Ferric ions can be reduced using chemical reducing agents such as sulfur dioxide, sulfite, bisulfite, soluble sulfites and the like. In order to extract nickel and / or cobalt from the leaching solution, the latter is brought into contact with a soluble organic dithiophosphinic acid, or an alkali metal, alkaline earth metal or ammonium salt thereof. The extraction solvent of dithiophosphine type is advantageously represented by the formula:

R 'S R' S

P IP

R2 SM R SM

  in which R1 and R2 are the same or different and are alkyl, cycloalkyl, alkoxyalkyl, alkylcycloalkyl, aryl, alkylaryl, aralkyl, or substituted cycloaralkylaryl radicals, which has from 2 to 24 carbon atoms. Most advantageously, R1 and

  R2 represent each of the radicals 2,4,4-

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  trimethylpentyle; bis (2,4,4-trimethyl-

  The corresponding pentyl) dithiophosphine is available from Cytex Canada Inc. as the extraction solvent Cyanex 301. The substituent M can be hydrogen 5 when the extraction solvent is used in its acid form. Alternatively, M can be an alkali metal or alkaline earth metal ion or an ammonium ion when the extraction solvent is used in the form of its salt. Most advantageously, M is hydrogen. During solvent extraction, nickel and / or cobalt ions replace M, by charging

  thus the extraction solvent with metal ions. The extraction solvents are advantageously charged at temperatures between the freezing temperature and 15 85 C.

  While the metal is depleted, an acidic water-soluble solution provides the hydrogen necessary for

  replace the metal extracted in position M of the extraction solvent. The extraction solvent, exhausted in this way, is then recycled for another charge of nickel and / or cobalt ions.

  It has been found that chromium (VI) ions, if present in the aqueous loading solution, will cause a significant and rapid decrease in the metal extraction capacity of the organic extraction solvent of the dithiophosphine type. . Industrially viable operations require repeated use of the extraction solvent. Advantageously, the extraction solvent can be used at least ten times with only a reduction of 10% or less in the extraction capacity. Consequently, in order to protect the extraction solvent and / or to optimize its behavior during its use on a certain number of operations for the extraction and depletion of metals, oxidizing species which would not hydrolyze during the 'stage of

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  partial neutralization, such as chromium (VI) ions, are advantageously removed before solvent extraction using the organic extraction solvent of the dithiophosphine type. It is recognized that 5 when chromium (VI) concentrations are very low, a chromium (VI) removal step may not be required. Removal of chromium (VI) can be accomplished by a large number of techniques. For example, chromium (VI) can be easily removed by reduction and precipitation in the form of chromium (III) during the partial neutralization step. Advantageously, the reducing agent used to reduce chromium (VI) ions is a sulfur reducing compound, such as metabisulfide, gaseous sulfur dioxide or water-soluble sulfur. Alternatively, hydrogen peroxide can be used to reduce chromium (VI). Most advantageously, sulfur dioxide gas is used for the reduction of chromium (VI). It has further been found that copper ions, if present in the aqueous filler solution, bind very strongly with an organic extraction solvent of the dithiophosphine type. The bond formed between the dithiophosphine extraction solvent and the copper ions is so strong that it is theoretically impossible to exhaust the copper with the usual mineral acids. Consequently, in order to optimize the behavior of the extraction solvent, the copper ions are advantageously removed, before extraction by solvent using the diphosphine organic extraction solvent. It is recognized that, when the copper concentrations are very low, it is not necessary to carry out a copper elimination step. This removal of copper can be accomplished by a number of techniques. For example, copper ions can be

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  removed using an ion exchange resin. Most advantageously, the ion exchange resin is a chelating resin having iminodiacetic acid functionality. Other techniques which can be used for the removal of copper include, for example, carburizing and precipitation as copper sulfide. The organic dithiophosphine extraction solvent can be used in undiluted form. However, it is advantageous to use an organic diluent immiscible in water. This diluent can represent from 1 to 99% by volume of the diluent / organic extraction solvent mixture. Optionally, the diluent / solvent mixture of organic extraction can contain from 1 to 20 parts by weight of one or more of an additional organic compound soluble and immiscible with water, which is generally called general "phase modifiers", whose role, among others, is to improve the separation between the aqueous and organic phases. In addition, these compounds can help avoid the oxidation of cobalt (II) to cobalt (III) once loaded in the organic phase for example, when the solution is in contact with an oxidizing atmosphere such as air. A very large number of water-immiscible organic liquids can be used as a diluent. Suitable diluents include, but are not limited to kerosene, toluene, xylene, naphtha, hexane, decane, cyclohexane and the like. Advantageously, the diluent is a petroleum, aliphatic or aromatic product. Most advantageously, the diluent is an aliphatic petroleum liquid. The aliphatic petroleum liquid may contain, where appropriate, naphthenic and / or aromatic compounds. Examples of suitable phase modifiers include, without implying any

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  limitations, iso-decanol, tridecyl alcohol, nonyl-phenol, tributyl phosphate, trioctyl-phosphine oxide and the like. The solvent extraction technique can be carried out in an air atmosphere. However, when operating in air, some degradation of the extraction solvent can occur during solvent extraction (from the step of bringing the charged solution into contact with an organic phase up to 1 step 10 of bringing the charged organic phase into contact with a depletion solution). Thus, it is advantageous to use the solvent extraction technique under an inert gas or else a reducing gas atmosphere in order to avoid or limit the harmful effects, or the formation, of the oxidizing elements such as Fe (III ), and Co (III). For the purposes of the present invention, inert gas is defined as a gas which does not oxidize cobalt (II) to cobalt (III) or iron (II) to iron (III) in the aqueous solution and / or the organic phase. Examples of suitable gases include, without limitation, carbon dioxide, nitrogen, argon, sulfur dioxide and the like. Advantageously, if oxidizing elements such as Fe (III) are present in the charged aqueous solution, then the chemical reducing reagents, such as, without this providing any limitation, the anhydride

  sulfurous, sulfites, bisulfites, water-soluble sulfides and the like are advantageously added to reduce the oxidizing element. The reducing chemical reagent can be added before or during the extraction of metals.

  In order to implement the solvent extraction technique of the invention, mixing / decantation tanks, extraction columns such as pulse columns, columns with internal agitation

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  using rotary propellers, extraction columns with reciprocating trays, tubular reactors with circuit mixers and the like can be used.5 For a stable pH of less than about 4 and, advantageously, less than about 3, colbalt and nickel are loaded onto the organic dithiophosphine extraction solvent. Most advantageously, cobalt and nickel are loaded onto the organic dithiophosphine extraction solvent10 for a stable pH of less than 2.5 in order to ensure that the manganese is not co-loaded on the solvent d 'extraction. If the pH of the aqueous charge is greater than about 2.5, the addition of a base to neutralize the hydrogen ions released during extraction may not be necessary. Avoiding the addition of a base significantly facilitates the reduction of the operational costs of the solvent extraction process. Advantageously, the extraction pH is greater than about 1.0 in order to ensure efficient extraction of nickel and / or cobalt. Advantageously, at least about 60% of the nickel ions are loaded onto the extraction solvent. Most advantageously, at least about 95% of the nickel ions are charged to the extraction solvent. It has been discovered that a charge ratio of nickel to manganese of at least about 100 can be easily achieved when at least 60% of the nickel is extracted. In fact, separation ratios of at least 400 to 700 are typically achieved by the method of the invention. This exceptional ratio provides efficient separation of nickel and / or chromium, manganese, as well as calcium, magnesium and the like. The metal extraction reaction is very fast,

  which allows to operate at room temperature.

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  However, the extraction can also be carried out at high temperatures. Advantageously, the organic / aqueous mixture during the extraction is maintained at a temperature between the freezing temperature and 85 C. The ratio between the aqueous phase and the organic phase by extraction is advantageously maintained between 10 and 0 , 1, more advantageously between 5 and 0.5, and, most advantageously, between 3 and 1. After having loaded the organic dithiophosphine extraction solvent with nickel and cobalt, the metals nickel and cobalt can be exhausted with a water-soluble acid, separately or together. The cobalt ions can be exhausted separately, advantageously, using aqueous solutions having an acidity between 0.1 and 2.0 N, and more advantageously less than that of a 1N hydrochloric acid or its equivalent for a another acid or another combination of acids. Once the cobalt has been removed, the nickel can advantageously be exhausted with the same water-soluble acid or a different species of water-soluble acid, the concentration of the acid being at least that of '' hydrochloric acid 1, ON or its equivalent for another acid or a combination of acids. Most advantageously, the acid concentration is between about 2.0 N and 8.0 N for the removal of nickel. Depletion of the metal can be achieved using, for example, usual mineral acids such as sulfuric acid or hydrochloric acid, and the like, or mixtures thereof. Advantageously, either hydrochloric acid or sulfuric acid is used. Most advantageously, hydrochloric acid is used for the depletion of metals. Advantageously, the nickel is exhausted with the organic phase, the aqueous acid solution

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  being at a temperature between 45 C and 85 C. Advantageously, the acid depletion solutions are

  internally recycled during the depletion process to obtain depletion solutions5 more concentrated in nickel and / or cobalt.

  Alternatively, nickel and cobalt can be separated by selective charge of nickel relative to cobalt. Under conditions very close to the maximum metal loading capacity of the organic dithiophosphine extraction solvent, the nickel ions present in the aqueous loading solution can be loaded onto the extraction solvent by displacing the cobalt up to the aqueous phase. . The organic extraction solvent is then essentially charged only with nickel. The cobalt in the aqueous solution can be extracted, suitably, using the same extraction solvent or another in a separate extraction step. When separate extraction stages are used for cobalt, the final stage of extraction of cobalt may require an upward adjustment of the pH to obtain an improved yield. The displacement of the cobalt by the nickel during the extraction makes it possible to obtain a nickel / cobalt separation which can be advantageous on the selective nickel / cobalt depletion with different acid concentrations for situations in which the initial charge concentration in nickel is significantly higher than the cobalt concentration. Alternatively, nickel and cobalt can be used up together with the dithiophosphine extraction solvent charged with a water-soluble acid, the concentration of this acid being at least 1.0 N. More preferably, the acid and hydrochloric acid is used in concentrations between 2.0 N and 8.0 N. Nickel and cobalt

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  can then be separated later by means of

  known solvent extraction processes. Advantageously, the nickel and the cobalt are separated by selective extraction of the cobalt using an amino extraction solvent5. Most advantageously, the amino extraction solvent is triisooctylamine.

  It is advantageous, for economic reasons, to regenerate the acid from the nickel and / or cobalt depletion solutions. For example, thermal decomposition of the respective nickel and / or cobalt salts of the depletion solutions can be carried out in order to

  to obtain a nickel and / or cobalt oxide and to regenerate the acid so that the latter is advantageously recycled for another depletion of the nickel and / or cobalt.

  The following examples are for illustration purposes only and should not be considered as

  limiting the invention in any way, since modifications of the invention are possible which do not depart from the spirit or the scope of the appended claims.

  Example 1 This example shows that the complete extraction of nickel (II) and cobalt (II) is possible, without extract of manganese (II), calcium (II), magnesium (II) or chromium (III), using a dithiophosphine organic extraction solvent for low pH conditions. A sample of a 15% by volume solution of the extraction solvent Cyanex 301 in the diluent Isopar M (an aliphatic organic solvent from Imperial Oil) is brought into contact at a temperature of 23 ° C. and for different pH values (adjusted with a sodium hydroxide solution), for 5 minutes and a ratio between the aqueous phase and the organic phase (A / O) of 2,

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  using a sulfate solution containing, in g / l, 0.045 copper (II), 3.86 nickel (II), 0.35 cobalt (II), 0.002 iron (III), 2 , 24 of manganese (II), 0.54 of calcium (II), 1.54 of magnesium (II), 0.094 of zinc (II), 0.004 of chromium (III) and 0.005 of aluminum (III). Samples from each phase are taken after a contact time of 5 minutes. The metal concentrations analyzed in the resulting aqueous phase are specified in Table Ia below: 10 Table Ia pH Test on the refined product (g / l) Cu (II) Ni (II) Co (II) Mn (II) Zn (II)

1.46 <0.001 0.410 0.040 2.28 0.001

1.61 <0.001 0.57 0.033 2.28 <0.001

1.83 <0.001 0.006 0.016 2.23 <0.001

2.01 <0.001 0.002 0.008 2.19 <0.001

  2.54 <0.001 <0.001 <0.001 2.18 <0.001

  The concentrations of Cr (III), Al (III), Ca (II), and Mg (II) remain the same as those present in the aqueous charge. The respective extraction percentages for Ni (II), Co (II) and Mn (II) are specified in table lb below: Table lb pH Extraction (%) Ni Co Mn

1.46 89.4 88.6 0

1.61 98.5 90.6 0

1.83 99.8 95.4 0.4

2.01 99.95 97.7 2.2

2.54> 99.9> 99.9 2.7

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  Claim 2: This example illustrates a variant for

  selectively loading nickel (II) into a dithiophosphine organic extraction solvent in order to achieve an effective nickel / cobalt separation. 5 i) selective loading of nickel.

  A 15% by volume sample of the extraction solvent Cyanex 301 in an Isopar M diluent is brought into contact at a temperature of 23 ° C. for 5 minutes at an A / O ratio of 2 and at pH 2.5 (adjusted to 1 using a sodium hydroxide solution) with a sulphated filler solution containing, in g / l, 0.002 of copper (II), 2.15 of nickel (II), 0.25 of cobalt (II), <0.001 iron (III), 1.18 manganese (II), 0.51 calcium (II), 0.58 magnesium (II), 0.037 zinc (II), 0.020 chromium (III) and 0.007 aluminum (III). Once the two phases have been separated, the aqueous refined product contains in g / l, <0.001 copper (II), <0.001 nickel (II), <0.001 cobalt (II), <0.001 iron (III), 1 , 09 manganese (II), 0.51 calcium (II), 0.56 magnesium

  (II), <0.001 zinc (II), 0.028 chromium (III) and 0.004 aluminum (III).

  The charged organic phase is then brought into contact, for a second period of time, with another part of the solution charged with sulfate in an A / O ratio of 3 and, moreover, under the same conditions. After 5 minutes of contact time, followed by phase separation, the aqueous raffinate phase contains in g / l <0.001 copper (II), 0.78 nickel (II), 0.36 cobalt ( II), <0.001 iron (III), 1.2 manganese (II), 0.51 calcium (II), 0.58 magnesium (II), <0.001 zinc (II), 0.021 chromium (III ) and 0.006

aluminum (III).

  The charged organic phase is then brought into contact, for a third period of time, with another part of the sulfate-loaded solution for the

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  same A / O ratio of 3 and under the same other conditions. After 5 minutes of contact time, followed by phase separation, the aqueous raffinate contains in g / l, <0.001 copper (II), 2.30 nickel (II), 0.315 cobalt (II), <0.001 iron (III), 1.2 manganese (II), 0.52 calcium (II), 0.59 magnesium (II), 0.005 zin (II), 0.022 chromium (III) and 0.004 aluminum

(III).

  Following these three consecutive contacts of the organic phase with fresh portions of the same solution loaded with sulfate, the charged organic phase obtained

  is analyzed and has been found to contain, in g / l 0.023 of copper, 9.33 of nickel, 0.038 of cobalt, 0.004 of iron, <0.005 of manganese and 0.272 of zinc.

  ii) depletion of nickel A portion of organic phase, similarly charged, is brought into contact with a 5N hydrochloric solution for 40 minutes at a temperature of 55 C. After the phase separation, the exhaustion liquor has been found to contain in g / l, <0.001 copper (II), 5.99 nickel (II), 0.03 cobalt (II), <0.001 iron (III), 0.003 manganese (II), 0.002 calcium (II), 0.003 magnesium (II), 0.51 zinc (II),

  0.002 chromium (III) and 0.004 aluminum (III).

  Example: This example illustrates the depletion of nickel and cobalt from the charged organic dithiophosphinic extraction solvent, using sulfuric acid. A 15% by volume sample of the extraction solvent Cyanex 301 in the diluent Isopar M, loaded up to approximately 7.6 g / l of Ni (II), 0.5 g / l of Co (II), and 0.12 g / l of Zn (II) is brought into contact with a 3.0N sulfuric acid solution in an A / O ratio of 1 for a temperature of 55 ° C. for 50 minutes. The aqueous exhaustion liquor obtained contains 3.7 g / l of Ni (II), 0.5 g / l of Co (II) and 0.02 g / l of Zn (II), which 22a 2717826 is l 'equivalent of depletion at 45% nickel,> 99.9% cobalt and 15% zinc. Exemnl._e: This example illustrates the complete extraction of nickel (II) and cobalt (II) using a solvent 5 of organic dithiophosphinic extraction with the simultaneous total elimination of manganese (II), calcium ( II), magnesium (II) and chromium (III). This example further illustrates the separation of nickel (II) and cobalt (II) by selective exhaustion of the thiophosphinic organic extraction solvent in a counter-current, multi-step and continuous solvent extraction treatment. An aqueous sulphated solution containing in g / l, 05 of nickel (II), 0.53 of cobalt (II), <0.001 of iron (III), 2.93 of manganese (II), 0.48 of calcium ( II), 1.03 magnesium (II), 0.074 zinc (II), 0.044 chromium (III) and 0.005 aluminum (III), having a pH of 3.6 at a temperature of 22 C, is brought in contact, in a countercurrent manner in three consecutive extraction stages, (steps L1, L2 and L3; the aqueous solution enters into operation in step L3 and leaves the operation (as a refined product) in step L1) at a flow rate of 10 ml / min and at a temperature of 41 C using a 15% by volume solution of the extraction solvent Cyanex 301 in an Isopar M diluent. The organic solution enters the operating cycle in step L1 and has the same flow rate of 10 ml / min in order to obtain an A / O ratio of 1, with a retention time of 6 minutes per step. No base is added to any of the extraction steps for setting or controlling the pH. The charged organic solution leaving step L3 is brought into contact in a countercurrent manner in two consecutive depletion steps (steps Cl and C2) at a temperature of 33 C using a solution of 1N hydrochloric acid, at flow rate

23 2717826

  flow rate of 0.8 ml / min in order to obtain a ratio between the organic phase and the aqueous phase (O / A) of 12.5 (the 1N hydrochloric acid solution entering the operating cycle in step C2 and leaving the operating cycle5 (in the form of a cobalt depletion solution) in step Cl). The organic solution is eliminated in step C2 and then brought into contact in a countercurrent manner in a washing step (step W1) at a temperature of 30 C with water, which has a flow rate. 0.5 ml / min in order to obtain an A / O ratio of 20. The organic phase partially exhausted and washed and brought into contact, once it has left the backwashing stage in four stages consecutive exhaustion (stages N1, N2, N3 and N4) with a 6N hydrochloric acid solution, at a flow rate of 2.3 ml / min, in order to obtain an O / A ratio of 4.3 (the 6N hydrochloric acid solution enters the operating cycle at stage N4 and is then eliminated from the operating cycle in the form of a nickel depletion solution in stage N1). The depletion steps are maintained at a temperature of 60 C. The organic phase devoid of metals is eliminated in step N4 then is brought into contact against the current in a washing step (step W2) at a temperature of 34 C with water, at a flow rate of 0.4 ml / min in order to obtain an O / A ratio of 25. The organic phase, washed and depleted of metals, is then recycled to the extraction stages (step L1). Typical compositions of aqueous solution after

  each step, together with their pH values if any, are specified in Table 2.

24 2717826

Table 2

  Step Temp pH * Analysis of aqueous solutions (mg / l) "C Ni Co Mn Cr Ca Mg Zn

(II) (II) (II) (III) (II) (II) (II

  L1 (prod. 41 1.30 43 46 3.040 52 560 1.240 <1 refined)

  L2 41 1.53 680 990 3.030 52 560 1.230 <1

  L3 40 2.36 3.510 1.630 3.050 53 560 1.230 3

  Cl (liquor 33 0.28 1,960 3,730 2 3 <1 1,160 cobalt depletion)

  C2 33 0.23 1.260 550 <1 <1 <1 <1 110

  N1 (liquor 60 - 18,200 35 <11 4 <1 <1,270 of nickel exhaustion)

N2 60 - 5.380 2 <1 <1 <1 <1 <1

N3 60 - 1,580 <1 <1 <1 <1 <1 <1

N4 60 - 450 <1 <1 <1 <1 <1 <1

W2 34 2.36 <1 <1 <1 <1 <1 <1 <1

  * Measured at the corresponding temperature. Example 5: This example illustrates the treatment of an acid solution containing nickel and cobalt, which involves the reduction of chromium (VI) using dioxide.

  sulfur gas followed by partial neutralization.

  An aqueous sulphated solution, which contains in g / l, 0.017 of copper, 3.29 of nickel, 0.33 of cobalt, 0.24 of iron (III), 2.45 of manganese, 0.5 of chromium (VI ), 0.18 calcium, 0.89 aluminum, 0.079 zinc and 2.44 magnesium, which has a pH of about 1.0 and a redox potential of 800 mV, measured using

2717826

  a saturated calomel electrode, brought into contact with

  sulfur dioxide gas at about 60 C to the lower redox potential up to about 800 mV, measured against a saturated calomel electrode. 5 Following this treatment, calcium carbonate is added to the solution to reach a pH of 4.5 to 60 C.

  After removal of the precipitated solids, the solution contains, in g / l, <0.008 copper, 3.18 nickel, 0.31 cobalt, <0.01 iron, 2.18 manganese, 0.074 chromium (III ) (no trace of chromium (VI) is detected), 0.89 calcium, 0.01 aluminum, 0.077 zinc and 2.18 magnesium. Example 6: This example shows that relatively small amounts of copper (II) which may be present in the charged aqueous solution can be selectively removed prior to solvent extraction using ion exchange resins chelating. An aqueous solution loaded with sulphate, which contains in g / l, 0.20 of copper (II), 3.5 of nickel (II), 0.33 of cobalt (II), 2.2 of manganese (II), 0.5 of calcium (II), 1.5 of magnesium (II) and 0.087 of zinc (II), is introduced at an ascending flow rate of 1.2 m / h and at a temperature of 23 C through a column which contains 100 ml of Resin Tech SIR-300 chelating resin (from Resin Rech, Inc.) which exhibits iminodiacetic acid functionality. After the passage of 80 bed volumes of solution, the treated sulphated solution contains still less than 0.00130 g / l of copper (II), while the concentrations of nickel (II) and cobalt (II) remain the same as those in the loaded solution. The process of the invention provides several advantages. The subject of the invention is a method for selectively recovering the metals of interest

26 2717826

  nickel and / or cobalt from aqueous acid solutions using solvent extraction which avoids the co-extraction of manganese, calcium and magnesium. The process of the invention facilitates the selective, simple and economical recovery of nickel and / or cobalt. The organic phase is typically reusable during many extraction / depletion cycles. The method further provides efficient separation of nickel from cobalt by selective depletion options or selective charging methods. Finally, the addition of bases during the metal loading step is not always necessary when a partial neutralization is carried out in order to remove the impurities. It is clear that although the invention has been described and illustrated by embodiments

  Specific, it encompasses all modifications and variants, within the reach of ordinary skill in the art, which fall within the scope of the protection conferred on this invention by the appended claims.

27 2717826

Claims (58)

  1. A hydrometallurgical process for the recovery of metals, characterized by the steps of: a) implementing a charged aqueous solution, this charged aqueous solution originating from an acid leaching and containing at least one metal chosen from the group consisting of ions nickel and cobalt; b) maintain the pH of said aqueous solution in the range of about 2 to 6, c) contact said charged aqueous solution with an organic phase immiscible in water, which contains an extraction solvent in order to charge the metal of said aqueous solution loaded on said extraction solvent and of producing an organic phase containing metals, this extraction solvent comprising at least one soluble organic dithiophosphinic acid or one of its alkali or alkaline-earth metal salts or d ammonium and said charged aqueous solution having sufficiently low levels of chromium (VI) ions, iron (III) ions and copper ions to allow repeated use of said extraction solvent, d) separating said organic phase containing metals of said aqueous loaded solution containing metals, and e) contacting said organic phase containing metals with an aqueous depletion solution in order to recover said m charged stall originating from said organic phase containing metals. 30 2. The method of claim 1 comprising the additional step of removing copper ions from said charged aqueous solution before bringing it into contact with said water-immiscible organic phase. 3. The process according to claim 1, wherein the chromium (VI) ions are removed by reduction using 28 2717826   a reducing agent before being brought into contact with said water-immiscible organic phase. 4. The process according to claim 1, wherein said soluble organic dithiophosphinic acid or one of its alkali or alkaline earth metal salts or one of its ammonium salts is represented by the formula: R 'S R $ S p IP RI SM R {SM   in which R1 and R2 are chosen from the group consisting of alkyl, cycloalkyl, alkoxyalkyl, alkylcycloalkyl, aryl, alkylaryl, aralkyl or   substituted cycloalkylaryl which contain from 2 to 24 carbon atoms and in which M is hydrogen or an alkali metal or alkaline earth metal ion, or alternatively an ammonium ion.   5. The process of claim 1, wherein said extraction solvent is bis (2,4,4-   trimethylpentyl) dithiophosphine. 6. The method of claim 1, wherein   said organic phase immiscible in water comprises an organic diluent.   7. The method of claim 1, wherein said charged aqueous solution and said non-organic phase   miscible in water are brought into contact at a temperature from the freezing point to C. 8. The method of claim 1, wherein said aqueous depletion solution contains at least one   mineral acid selected from the group consisting of hydrochloric acid and sulfuric acid.   9. The process of claim 1, wherein said organic metal-bearing phase contains nickel and 29 2717826   cobalt, and said organic phase containing metals is brought into contact with said aqueous depletion solution having a pH of less than 2.5. 10. The method according to claim 1, in which said extraction solvent is loaded with nickel ions and cobalt ions, and the contacting of said organic phase containing metals with an aqueous exhaust solution comprises the steps of bringing said organic phase carrying metals into contact with a first aqueous depletion solution in order to recover the cobalt ions and of separating this first aqueous depletion solution from the organic phase carrying metals, after which said organic phase is brought into contact containing metals, once the separation of cobalt has been carried out with a second aqueous depletion solution in order to recover   the nickel ions of the organic phase containing metals and to obtain an organic phase devoid of cobalt / nickel, after which said second aqueous depletion solution is separated from the organic phase devoid of cobalt / nickel.   11. The method of claim 10, wherein said cobalt ions are depleted using the first aqueous depletion solution which has an acid concentration between about 0.1 and 2.0 N while the nickel ions are depleted using the second aqueous depletion solution which has an acid concentration of at least about 1.0 N. The method according to claim 1, wherein the charged aqueous solution contains nickel and cobalt ions and said extraction solvent is charged with nickel and cobalt ions while the charged cobalt ions are displaced by an additional charge of ions nickel from the charged aqueous solution to achieve 2717826   an organic phase loaded with nickel, free of cobalt and an aqueous solution rich in cobalt. 13. The method according to claim 1, wherein said charged aqueous solution contains nickel ions and cobalt ions while said extraction solvent is charged with nickel ions and cobalt ions, these nickel ions and these cobalt ions being recovered. jointly during contact with the aqueous depletion solution. 10 14. The method of claim 13, wherein the nickel ions and the cobalt ions are separated using a solvent extraction method using an amino extraction solvent. 15. The method according to claim 1, wherein said metal from the aqueous depletion solution is recovered in the form of oxide by thermal decomposition so that the regenerated acid from the aqueous acid depletion solution, free of metal is recycled in step e) .20 16. The method according to claim 1, in which the charged aqueous solution contains manganese ions and a majority of the manganese ions are not loaded on said extraction solvent. 17. The method according to claim 1, comprising   the additional step of reducing ferric ions to ferrous ions before or during step c).   18. The method according to claim 1, in which steps c) to e) are carried out under an atmosphere which limits the oxidation of an ion chosen from the group   consisting of Co (II) ions and Fe (II) ions in the aqueous charged solution or in the organic phase.   19. A hydrometallurgical process for the recovery of metals, characterized in which comprises the steps of: a) implementing a charged aqueous solution, this charged aqueous solution coming from a leaching 31 2717826   acid of an ore and comprising a first group of metals and a second group of metals, the first group of metals having at least one metal chosen from the group consisting of nickel and cobalt ions while the second group of metals comprises at least one metal chosen from the group of ferric or chromium, aluminum and copper ions, b) partially neutralize the charged solution up to a pH in the range of about 2 to 6, in order to remove the free acid from this charged aqueous solution and precipitating the metals of the second group of metals, this neutralization leaving a majority of ions from the first group of metals in the charged aqueous solution, c) separating the precipitated metal from the charged aqueous solution, d) bringing the aqueous solution loaded with an organic phase immiscible in water, which contains an extraction solvent in order to load the metal 20 of the first group of metals onto said extraction solvent and real iser an organic phase containing the metal, this extraction solvent comprising at least one soluble organic dithiophosphinic acid or one of its alkali or alkaline earth metal or ammonium salts while said charged aqueous solution has sufficiently low levels of ions chromium (VI), iron (III) and copper ions to allow repeated use of said extraction solvent, e) separating said organic phase containing metals from said aqueous loaded solution containing metals, and f) putting in contact with the organic phase containing metals with an aqueous depletion solution in order to 32 2717826   recovering said metal from said first group of metals in the organic phase containing the metals. 20. The method according to claim 19, comprising the additional step of removing the copper ions from said charged aqueous solution before bringing it into contact with said water-immiscible organic phase. 21. The method of claim 19, wherein the chromium (VI) ions are removed by reduction using   a reducing agent before being brought into contact with said water-immiscible organic phase.   22. The process according to claim 19, wherein said soluble organic dithiophosphinic acid or one of its alkali or alkaline earth metal salts or one of its ammonium salts is represented by the formula: R 'S R' S p IP R2 SM R SM   wherein R1 and R2 are selected from the group consisting of substituted alkyl, cycloalkyl, alkoxyalkyl, alkylcycloalkyl, aryl, alkylaryl, aralkyl or cycloalkylaryl radicals which have from 2 to 24   carbon atoms and in which M is hydrogen or an alkali metal or alkaline earth metal ion, or an ammonium ion.25 23. The process of claim 19, wherein said extraction solvent is bis (2,4,4-   trimethylpentyl) dithiophosphine. 24. The method of claim 19, wherein said water-immiscible organic phase comprises an organic thinner.   25. The method of claim 19, wherein said charged aqueous solution and said organic phase 33 2717826   immiscible in water are brought into contact with a   temperature from freezing point to 85 C.   26. The method of claim 19, wherein said aqueous depletion solution contains at least one mineral acid selected from the group consisting of hydrochloric acid and sulfuric acid. 27. The method of claim 19, wherein said organic phase carrying metals contains nickel and cobalt, and said organic phase containing metals is contacted with said aqueous depletion solution having a pH of less than 2.5 . 28. The method according to claim 19, in which said extraction solvent is loaded with nickel ions and cobalt ions, and the contacting of said organic phase containing metals with an aqueous exhaust solution comprises the steps of bringing said organic phase carrying metals into contact with a first aqueous depletion solution20 in order to recover the cobalt ions and of separating this first aqueous depletion solution from the organic phase carrying metals, after which said organic phase is brought into contact containing metals, once the separation of cobalt has been carried out, with a second aqueous depletion solution in order to recover the nickel ions from the organic phase containing   metals and to obtain an organic phase devoid of cobalt / nickel, after which said second aqueous depletion solution is separated from the organic phase devoid of cobalt / nickel.   29. The method of claim 28, wherein said cobalt ions are depleted using the first aqueous depletion solution which has an acid concentration between about 0.1 and 2.0 N while the nickel ions are exhausted using the second 34 2717826   aqueous depletion solution which has an acid concentration of at least about 1.0 N. 30. The method of claim 19, wherein the charged aqueous solution contains nickel and cobalt ions and said extraction solvent is charged with nickel and cobalt ions while the charged cobalt ions   are displaced by an additional charge of nickel ions from the charged aqueous solution in order to produce an organic phase charged with nickel, devoid of cobalt and an aqueous solution rich in cobalt.   31. The method according to claim 19, in which said charged aqueous solution contains nickel ions and cobalt ions while said extraction solvent is loaded with nickel ions and cobalt ions, these nickel ions and these cobalt ions being recovered. jointly during contact with the aqueous depletion solution. 32. The method of claim 31, wherein the nickel ions and the cobalt ions are separated using   of a solvent extraction process using an amino extraction solvent.   33. The method of claim 19, wherein said metal from the aqueous depletion solution is recovered as oxide by thermal decomposition so that the regenerated acid from the aqueous acid depletion solution, free of metal is recycled in step f). 34. The method according to claim 19, in which the charged aqueous solution contains manganese ions and   a majority of the manganese ions are not loaded on said extraction solvent.   35. The method of claim 19, wherein the charged aqueous solution is neutralized to a pH between about 3 and 6. 2717826   36. The process according to claim 19, wherein said charged aqueous solution is partially neutralized by means of calcium carbonate. 37. The method according to claim 19, comprising the additional step of reducing the ferric ions into ferrous ions after step c) and before or during step d). 38. The method according to claim 19, in which steps d) to f) are carried out under an atmosphere which limits the oxidation of an ion chosen from the group consisting of Co (II) ions and Fe ( II) in the aqueous loaded solution or in the organic phase. 39. A hydrometallurgical process for the recovery of metals, characterized in that it comprises the steps of: a) using a charged aqueous solution, this charged aqueous solution originating from an acid leaching of an ore of laterite type, this charged aqueous solution containing chromium (VI) ions and comprising a first group of metals, a second group of metals and a third group of metals, said first group of metals having at least one metal chosen from the group consisting of nickel ions and cobalt, while the second group of metals comprises at least one metal chosen from the group of ferric ions, chromium (III), aluminum and copper, the third group of metals having at least one metal chosen from the group consisting of manganese, calcium and magnesium. B) reduce the chromium (VI) ions present in the aqueous solution charged with chromium (III) ions and partially neutralize this aqueous leaching solution up to a pH between about 3 to 6, in order to eliminate the free acid of the charged aqueous solution 35 and of precipitating the metals of the second group of metals, 36 2717826   this neutralization leaving a majority of ions from the first group of metals in the charged aqueous solution, c) separating the precipitated metal from the charged aqueous solution, d) bringing the charged aqueous solution into contact with an organic phase immiscible in the water, which contains an extraction solvent in order to charge the metal of the first group of metals to said extraction solvent and to produce an organic phase containing the metal, this extraction solvent comprising at least one soluble organic dithiophosphinic acid or one of its alkali or alkaline earth metal or ammonium salts in order to conserve said ions of the third group of metals in a resulting solution of refined product, this charged aqueous solution having sufficiently low levels of chromium (VI) ions, of ions iron (III) and copper ions in order to allow repeated use of said extraction solvent, e) separating said organic phase containing nt metals of the said refined product solution which contains the ions of the third group of metals, and f) bringing the organic phase containing the metals into contact with an aqueous depletion solution in order to   recovering the metal of said first group of metals from the organic phase containing the metals.   40. The method of claim 39, including the further step of removing copper ions from   said charged aqueous solution before bringing it into contact with said water-immiscible organic phase.   41. The method of claim 39, wherein the chromium (VI) ions are removed by reduction using   a reducing agent of the sulfur dioxide gas type.   42. The process according to claim 39, wherein said soluble organic dithiophosphinic acid or one of its alkali or alkaline earth metal salts or one of its ammonium salts is represented by the formula: 5 R 'S RI S p IP R2 SM R / SM   wherein R1 and R2 are selected from the group consisting of alkyl, cycloalkyl, alkoxyalkyl, alkylcycloalkyl, aryl, alkylaryl, aralkyl or substituted cycloalkylaryl radicals which have from 2 to 24 carbon atoms and in which M is hydrogen or an ion of alkali metal or alkaline earth metal, or else an ammonium ion. 43. The method of claim 39, wherein said   extraction solvent is bis (2,4,4-trimethylpentyl) dithiophosphinic acid.   44. The method according to claim 39, wherein said water-immiscible organic phase comprises an organic diluent. 45. The method of claim 39, wherein said charged aqueous solution and said organic phase   immiscible in water are brought into contact at a temperature from the freezing point up to 85 C.   46. The method according to claim 39, wherein said aqueous depletion solution contains at least one mineral acid selected from the group consisting of hydrochloric acid and sulfuric acid. 47. The method of claim 39, wherein said organic metal-bearing phase contains nickel and cobalt, and said organic phase containing 38 2717826   metals is brought into contact with said aqueous depletion solution having a pH of less than 2.5. 48. The method according to claim 39, in which said extraction solvent is loaded with nickel ions and cobalt ions, and the contacting of said organic phase containing metals with an aqueous exhaust solution comprises the steps of bringing said organic phase carrying metals into contact with a first aqueous depletion solution 10 in order to recover the cobalt ions and of separating this first aqueous depletion solution from the organic phase carrying metals, after which said organic phase is brought into contact containing metals, once the separation of cobalt has been carried out with a second aqueous depletion solution in order to recover the nickel ions from the organic phase containing   metals and to obtain an organic phase free of cobalt / nickel, after which said second aqueous depletion solution is separated from the organic phase free of cobalt / nickel.   49. The process of claim 48, wherein said cobalt ions are depleted using the first aqueous depletion solution which has an acid concentration between about 0.1 and 2.0 N while the nickel ions are depleted using the second aqueous depletion solution which has an acid concentration of at least about 1.0 N. 50. The method of claim 39, wherein the charged aqueous solution contains nickel and cobalt ions and said extraction solvent is charged with nickel and cobalt ions while the charged cobalt ions   are displaced by an additional charge of nickel ions coming from the charged aqueous solution in order to produce an organic phase charged with nickel, devoid of cobalt and an aqueous solution rich in cobalt. 39 2717826   51. The method according to claim 39, wherein said charged aqueous solution contains nickel ions and cobalt ions while said extraction solvent is charged with nickel ions and cobalt ions, these nickel ions and these cobalt ions being recovered. jointly during contact with the aqueous depletion solution. 52. The method of claim 51, wherein the nickel ions and the cobalt ions are separated using   of a solvent extraction process using an amino extraction solvent.   53. The method according to claim 39, wherein said metal from the aqueous depletion solution is recovered in the form of oxide by thermal decomposition so that the regenerated acid from the aqueous acid depletion solution, free of metal is recycled in step f). 54. The method of claim 39, wherein the charged aqueous solution contains manganese ions and   a majority of the manganese ions are not loaded on said extraction solvent.   55. The method of claim 39, wherein the charged aqueous solution is neutralized to a pH between about 3 and 5.5.25 56. The method according to claim 39, wherein said charged aqueous solution is partially neutralized by means of calcium carbonate. 57. The method of claim 39, including the further step of reducing ferric ions to   ferrous ions after step c) and before or during step d).   58. The method according to claim 39, in which steps d) to f) are carried out under an atmosphere which limits the oxidation of an ion chosen from the group consisting of Co (II) ions and Fe ions ( II) 2717826   in the aqueous loaded solution or in the organic phase.