MXPA00001843A - Process for the extraction of metals from ammoniacal solution - Google Patents

Abstract

A process for the solvent extraction of metals, particularly copper, from aqueous ammoniacal solutions is provided. The extractant is an orthohydroxyarylketoxime of Formula (1), wherein R1 is a hydrocarbyl group, and R2 is an ortho-hydroxyaryl group and the extraction process is carried out in the presence of a kinetic modifier. Suitable thermodynamic modifiers which can be employed include alkylphenols, alcohols, esters, ethers and polyethers, carbonates, ketones, nitriles, amides, carbamates, sulphoxides, and salts of amines and quaternary ammonium compounds. Preferred orthohydroxyarylketoximes are 5-(C9 to C14 alkyl)-2-hydroxyacetophenone oximes. Preferred modifiers are highly-branched alkyl esters comprising from 10 to 30 carbon atoms, or highly-branched alkanols comprising from 14 to 30 carbon atoms, or trialkyl phosphates wherein the alkyl groups comprise from 4 to 14 carbon atoms. Extractant compositions comprising a ketoxime and modifier are also provided.

Description

PROCESS FOR THE EXTRACTION OF METALS FROM AN AMMONIACAL SOLUTION FIELD OF THE INVENTION The present invention concerns a solvent extraction process and especially a process for the extraction of metals, particularly copper, from aqueous ammonia solutions, especially solutions obtained by the leaching of minerals, with ammonia.

BACKGROUND OF THE INVENTION It is known to extract metals, especially copper, from aqueous solutions containing the metal in the form, for example, of a salt, by contacting the aqueous solution with a solution of an extraction solvent in an organic solvent immiscible in water and then separating the solvent phase loaded with metal, that is, containing at least a part of the metal in the form of a complex. The metal can then be recovered by reextraction with REF. : 32781 solution of lower pH, followed, for example, by the electrolytic extraction. What is most commonly presented is that the aqueous solutions containing the metal, for extraction, are the result of the acid leaching of the minerals. However, it is known that copper can be leached preferably from certain minerals, with ammoniacal solutions. This has the advantage that solutions containing especially high concentrations of copper are derived and that there is little contamination of the solution with iron. Extractive solvents which have been found to be favorable in recent years, particularly for the recovery of copper from aqueous acid solutions, include oxime reagents, especially o-hydroxyl esters. Although these reagents have been found to work extremely well in the recovery of copper from acid solutions, problems have been encountered in the application of these reagents to the extraction from ammoniacal solutions. One of these problems results from the high concentrations of copper ^ j ^ and ^^^ j found in the ammoniacal solution. This can cause a very high copper load in the organic solutions which results in the viscosity of the organic solution increasing to a point where the solution may be difficult to process on an industrial scale. EP-A-0 036 401 solves this problem by the use of an extraction composition comprising two extraction solvents, wherein one is a strong solvent for extraction of the copper, such as an oxime, and the other is a solvent of weak extraction, such as a bet a-di ce t ona. The use of be t-di ce tones is also described in WO 93/04208, where these are the preferred extraction solvent and the only type that is exemplified. It has now been discovered that beta-diketones can suffer from poor chemical stability in the presence of the aqueous ammoniacal solution, leaching, and therefore quickly lose their effectiveness and form undesirable impurities. Alternative extraction solvents, contemplated by WO 93/04208, or to hydroxyl aldoximes, which have been shown to be the most suitable extraction solvents MMte rt-k effective for copper, of acid solutions, also suffer from problems with stability under the conditions of ammoniacal leaching. In addition, most extraction solvents are designed for use in acid leach systems, and operate at a relatively low pH. WO 93/04208 discloses that using extraction solvents designed for use with acid solutions in an ammonia system leads to ammonia entrainment to the reextraction solution and results in an unacceptable loss of ammonia from the system. It is described that ammonia entrainment requires additional treatment of the organic phase to remove the charged ammonia. Among the reagents which are not beta-diketones, contemplated by WO 93/04208, there are three ketoximes, the oxime of 5-nonyl-2-hydroxyacetyone, the oxime of 5-nonyl-2-hydroxylbenzoinone and the oxime of 5-dodecyl-2-hydroxybenzofenone. These reagents are described as equivalent to aldoximes, as less preferred alternatives for beta-says tones. It is disclosed that the extraction solvents based on be t-diethione and oxime, contemplated by WO 93/04208, are soluble, to the necessary degree, in the water-immiscible solvents commonly employed in solvent extraction. WO 93/04208 discloses that for extraction solvents other than be t-di ce tona s and oximes, a solubility modifier such as an alcohol or an ester may be employed, where the solubility of the extraction solvent needs to be increased. . During the course of the studies that led to the present invention, it was discovered that one or more of the problems of poor chemical stability, solution viscosity and ammonia transfer could be alleviated by the use of an extraction solvent comprising an ortho dr ixoar i 1 ce t oxime and a thermodynamic modifier.

DESCRIPTION OF THE INVENTION In accordance with a first aspect of the present invention there is provided a process for the extraction of a metal, from an ammonia solution, in which an aqueous, ammoniacal solution, containing a dissolved metal, is contacted with a solvent composition. of extraction comprising a water-immiscible organic solvent and a water-immiscible extraction solvent, whereby at least a fraction of the metal is extracted into the organic solution, characterized in that the extracting solvent composition comprises an orthohydroxy and Ice toxima and a thermodynamic modifier. The metals that can be extracted in the process according to the present invention include copper, cobalt, nickel and zinc, most preferably copper. The oxo-hydroxy compounds used in the present invention are substantially insoluble in water and have the formula: NOH Formula (1) wherein R 1 is a hydrocarbyl group which is optionally substituted, R 2 is an optionally substituted or t-hydroxy group, and salts thereof. Although the invention is described herein with reference to a compound of Formula (1), it is understood that it refers to that compound in any possible tautomeric forms, and also the complexes formed between the orthohi drox iari Icet oximes and the metals, particularly Copper. The hydrocarbyl groups, optionally substituted, which may be represented by R 1 preferably comprise the optionally substituted alkyl and aryl groups, including combinations of these, such as the optionally substituted aralkyl and alkaryl groups. Examples of optionally substituted alkyl groups, which may be represented by R1, include groups in which the alkyl portions may contain from 1 to 20, especially from 1 to 4, carbon atoms. A preferred orthohydroxy alcohol is one in which R 1 is alkyl, preferably containing up to 20, and especially up to 10, and more preferably up to 3, aliphatic, saturated carbon atoms. Most preferably R1 is a methyl group. Examples of optionally substituted aryl groups include the optionally substituted phenyl groups. When R1 is an aryl group it is preferably a phenyl group unsubstituted. Optionally substituted ortho-hydroxy aryl groups, which may be represented by R2, include the optionally substituted phenols. Examples of optionally substituted phenols that may be represented by R 2 include those of Formula: where of R; R 'represent each independently, H or an alkyl group, linear or branched, of 1 to 22 carbon atoms, preferably of 7 to 15 carbon atoms.

Particularly, preferably, only R 5 represents an alkyl group of 1 to 22 carbon atoms, most preferably an alkyl group of 7 to 15 carbon atoms and R 3, R 4 and R 6 represent H. When R 1 or R 2 are substituted , the substituent (s) must be one (s) that does not adversely affect the ability of the tohydroxy or ice to form complexes with metals, especially with the copper. Suitable substituents include halogen, nitro, cyano, hydrocarbyl, such as alkyl of 1 to 20 carbon atoms, especially alkyl of 1 to 10 carbon atoms; hydrocarbonyl, such as alkoxy of 1 to 20 carbon atoms, especially alkoxy of 1 to 10 carbon atoms; hydroxy loxi carboni 1 or, such as alkoxycarbonyl of 1 to 20 carbon atoms, especially alkoxycarbonyl of 1 to 10 carbon atoms; acyl, such as alkylcarbonyl of 1 to 20 carbon atoms and arylcarbonyl, especially alkylcarbonyl of 1 to 10 carbon atoms and phenylcarbonyl; and acyloxy such as alkylcarboni loxi of 1 to 20 carbon atoms and aryloxycarbonyl, especially 1 to 1 carbon and 1 to 1 carbon atoms and 1 carboni 1 oxy. There may be more than one substituent, in which case the substituents may be the same or different. In many preferred embodiments, the orthohydroxy and the oxime employed is an oxime of - (alkyl of 8 to 14 carbon atoms) -2-hydroxyaceto fone, particularly the oxime of -nonyl-2-hydroxyacetophenone. The composition may comprise one or more different hydroxy derivatives in which the nature of the substituent groups represented by R 1 and R 2 differ between the component orthohydroxyaryl-oximes, especially where the component orthohydroxyaryl-oximes are isomeric. These isomeric mixtures may have a better solubility in organic solvents than a tohydroxy or 1-oxime alone. Orthohydroxyarylketoximes are often present in an amount of up to 60% by weight of the composition, commonly not more than 50%, and usually not more than 40% w / w. Often, orthohydroxy ar i Ice toxima comprises at least 5% by weight, commonly at least 10% by weight and usually at least 20% by weight of the composition, and preferably comprises from 25 to 35%, such as about 30% by weight of the composition. The thermodynamic modifiers employed in the present invention are substantially insoluble in water. Suitable thermodynamic modifiers may be alkylphenols, alcohols, esters, ethers and polyethers, carbonates, ketones, nitriles, amides, carbamates, sulfoxides, and salts of amines and quaternary ammonium compounds. The alkyl phenols which can be used as modifiers together with the extraction solvent, include the alkyl phenols containing from 3 to 15 carbon atoms, for example 4-t ert-but i 1 phenol, 4-heptane and 1 pheno 1,5 -me ti 1 - 4 -pent i 1 phenol, 2 - c loro- 4 -noni 1 pheno 1, 2-ci ano - 4 -noni 1 pheno 1, 4 - dode ci 1 pheno 1, 3-pent adeci 1 f 1 and 4-nonylphenol ene and mixtures thereof. The preferred phenols contain alkyl groups having from 4 to 12 carbon atoms, especially the mixed 4 -noni-1-phenes obtained by condensation of the phenol and the propylene trimer.

The alcohols which can be used as modifiers together with the extraction solvent include the saturated and unsaturated hydrocarbon alcohols, and polyols containing from 14 to 30, preferably from 15 to 25, carbon atoms. The alcohols are preferably highly branched and their hydroxyl group is located approximately half the length of the hydrocarbon structure. Especially preferred are the branched chain alcohols which can be produced by the condensation of short chain alcohols through the Guerbet process, and those alcohols are sometimes referred to as Guerbet alcohols. Optically the alcohols may contain an aromatic group or other functional group, particularly an ester group. Especially useful alcohols can be synthesized from highly branched precursors which lead to highly highly branched Guerbet alcohols, which contain a large number of terminal methyl groups. Examples of particularly efficient alcohol modifiers include highly branched isohexadecyl alcohol and suitable alcohol and alcohol, where the latter is 2- (1,3,3-trimethylbutyl) -5, 7, 7-tr ime ti loe t an- 1 -o 1. The esters that can be used as modifiers together with the extraction solvent, include aliphatic and aromatic esters -al i fát i eos, saturated and unsaturated, containing 10 to 30 carbon atoms. The esters may be monoesters or polyesters, especially di-esters. The esters are preferably highly branched. Optionally, the esters may contain other functional groups, particularly a hydroxyl group or an ether group. Where the ester is a product of the reaction of an alcohol and a monocarboxylic acid, it is preferred that the alcohol is an alkyl alcohol and that it comprises from 1 to 6 carbon atoms, and that the monocarboxylic acid comprises 2 to 16 carbon atoms. Where the ester is a product of the reaction of an alcohol and a dicarboxylic acid, it is preferred that the alcohol is an alkyl alcohol and that it comprises from 1 to 6 carbon atoms, and that the dicarboxylic acid comprises from 4 to 12 carbon atoms. Where the ester is a product of the reaction of a diol and a monocarboxylic acid, it is preferred that the diol is an alkyl diol and that it comprises up to 6 carbon atoms, and that the monocarboxylic acid comprises from 6 to 16 carbon atoms. Where the ester is a metal phosphate, the alkyl groups each typically comprise from 4 to 14 carbon atoms. Examples of useful esters include isodecyl acetate, methyl decanoate, 2-pentyl octanoate, n-hexyl hexanoate, methyl isooctanoate, 1,4-bu tiodiol dihexanoate, butyl adipate, isobutyl adipate, adipose of bi-2 -e toxinyl, dibenzoate of dipropylene glycol, propylene glycol dibenzoate, tributyl phosphate, trioctyl phosphate and phosphate of triethylamine, and particularly isobutyrate of 2, 2, 4- t rime t il- 1, 3-pent anodiol and the benzoate of 2, 2, 4-trimethyl-l, 3-pentanediol. The ethers that can be used as modifiers together with the solvent of - ~ - * ~. ^ * m ~ ae ^. . * y ^ - ^ _-., .., -. ^ .. ^ ^^.

Extraction include hydrocarbon ethers and polyethers, containing from 12 to 30, preferably from 15 to 25, carbon atoms. Examples of useful ethers and polyethers include the ether 2 - (2-butoxy, toxy) and the benzyl ether and the 2-butoxyethylbenzyl ether. The carbonates that can be used as modifiers together with the extraction solvent, include the carbonates that contain from 4 to 16 carbon atoms. Commonly carbonates are alkyl carbonates. Examples of useful carbonates include isobutyl carbonate, isotridecyl carbonate and a mixture of carbonates which comprises a mixture of alkyl groups of 8 and 10 carbon atoms. Ketones that can be used as modifiers together with the extraction solvent include the alkyl ketones in Wherein the alkyl group contains from 1 to 20 carbon atoms. Examples of useful ketones include the I s obu t i lhep t i 1 ce t ona s, the Ice tona diundeci and 5, 8-di e ldodecan- 6, 7-dione. 25 Nitriles that can be used as modifiers together with the extraction solvent, include the aliphatic and araliphatic hydrocarbons which comprise from 10 to 36 carbon atoms. Examples of useful nitriles include the undecyl ether and oleoni thyl. Amides that can be used as modifiers together with the extraction solvent include the amides containing from 8 to 20 carbon atoms. The amides include products that can be derived from the reaction of a primary or secondary amine with a monocarboxylic acid or dicarboxylic acid, or equivalent, in particular phosgene or equivalents. Examples of useful amides include N, N'-bis-2-ethylhexylurea, N, N'-bis-2-ethylhexyl-2-ethylhexanamide, N-hexyl 2-ylhexanamide, N, N'-dibutyl. lben zami da, N, N 'dibut i loct anamida, N' N-dime ti 1 oct anami da and N, N '-bi s - 2 - eti lhexi 1 ve rsat ami da. The carbamates that can be used as modifiers together with the extraction solvent include the alkyl and aryl carbamates. Examples of useful carbamates include the I s or tri deci 1 N-octyl carbamate and - ^^^^^^ gjglgltoigj ^ íá ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^ The sulfoxides that can be used as modifiers together with the extraction solvent include the alkyl sulfoxides. An example of a useful sulfoxide is the sulfoxide of di-2 -ethexhoxy lo. The salts of amines and the quaternary ammonium compounds which can be used as modifiers together with the extraction solvent include the tertiary amines and the quaternary ammonium compounds containing alkyl groups having from 8 to 18 carbon atoms and the salts thereof. sulphonic acid thereof. Examples of sulphonic acids include the dinon-free acid din 1 to sulfonic acid and toluene sulfonic acid. In the context of the present invention, "highly branched" as applied to alcohols and esters, means that the ratio of the number of methyl carbon atoms to the non-methyl carbon atoms is greater than 1: 5 and preferably greater than 1: 3 If desired, mixtures of compounds selected from the group consisting of alkylphenols, alcohols, esters, ethers, polyethers, carbonates, ketones, nitriles, amides, carbamates, sulfoxides, and salts of amines and quaternary ammonium compounds may be employed as modifiers. Particularly preferred are mixtures comprising a first compound selected from the group consisting of alkylphenols, alcohols, esters, polyesters, carbonates, ketones, nitriles, amides, carbamates, sulfoxides, and salts of amides and quaternary ammonium compounds and a second selected compound of the group consisting of alkanols having from 6 to 18 carbon atoms, an alkyl phenol in which the alkyl group contains from 7 to 12 carbon atoms, and tributyl phosphate. Modifiers often comprise up to 20% w / w of the composition, preferably from 5 to 15% w / w, and most preferably from 8 to 12% w / w. The weight ratio of the modifier to ketoxime is often in the range of 10: 1 to 1:10, commonly 5: 1 to 1: 5 and preferably 1: 1 to 1: 4. The aforementioned modifiers | Ú | ^^ ^ g ^ ijjk above may be used in the preparation of extraction compositions containing one or more extraction solvents and one or more modifiers. 5 Organic solvents which can be used for the extraction include any mobile organic solvent, or mixtures of solvents, which are immiscible with water and which are inert under the extraction conditions to the other materials present. Examples of suitable solvents include aliphatic, alicyclic and aromatic hydrocarbons, and mixtures of any of these as such, as well as chlorinated hydrocarbons such as t r icloroe t i lo l, percl oroe t il ene, t r i f luo ro e t and chloroform. Examples of suitable hydrocarbon solvents include hydrocarbon solvents with low aromatic content (< 1% w / w) such as ESCAID 110 available commercially on Exxon (ESCAID is a trademark), and ORFOM SXll commercially available at Phillips Petroleum (ORFOM is a trademark). The preferred solvents are the hydrocarbon solvents that include solvents with high flash point and that ----- - ~ ^ - ~. - ~ • -. -... l-M-iA.rf -.- t.t -; ^ i. , ^ íai,, ...-... ^. ^^ -. «. M- ^ have a high content of aromatic products such as SOLVESSO 150 commercially available from Exxon (SOLVESSO is a trademark) and includes solvents consisting essentially of a mixture of trime thiolbenzenes such as AROMASOL H, commercially available in Imperial Chemical Industries PLC (AROMASOL is a trademark). However, because of their low toxicity and their wide availability, hydrocarbon solvents with a relatively low aromatic content such as kerosene are especially preferred, for example ESCAID 100 which is a petroleum distillate comprising 20% aromatic products, 56.6% paraffins and 23.4% naphthenes, commercially available from Exxon (ESCAID is a trademark), or ORFOM SX7, commercially available from Phillips Petroleum (ORFOM is a trademark). In many embodiments, the composition comprises at least 35%, often at least 45% by weight, preferably 50 to 70% w / w hydrocarbon solvent immiscible in water ico. The composition will comprise at least one ^^^^^^^^^^^ "^^^^^^^^" j ^^^^^ jg ^^^^^^^ or tohidroxiar i ce t oxime 1 may be present in an amount of up to 54% w / w / and preferably from 25 up to 35% w / w. A modifier, particularly an alkylphenol, alcohol or ester modifier, can be present in an amount of up to 20%, preferably from 5 to 15% w / w. Compositions comprising an ortho-hydroxy-1-oxime which is present in an amount of 25 to 35% w / w and an alkylphenol, alcohol or ester modifier which is present in an amount of 5 to 15% w / w , they are particularly preferred. The compositions of the extraction solvent, particularly preferred are those comprising 25 to 35% w / w of 5- (alkyl from 8 to 14 carbon atoms) -2 -hydroxy ace tof enone, 5 to 15% p / p of tridecanol, tributyl 1-phosphate, or isobutyrate of 2, 2, 4-trime thi-1,3, -pent anodiol or the benzoic acid ester thereof, and from 50 to 70% solvent hydrocarbon miscible in water. The aqueous ammonia solution from which the metals are extracted by the process of the present invention often has a pH that ^^^^^^^ jjgjgg ^ aj ^^^^^^^^^^^^^. it varies from 7 to 12, preferably from 8 to 11, and most preferably from 9 to 10. The solution can be derived from the leaching of minerals, particularly chalcocite minerals, or it can be obtained from other sources, for example, waste streams containing metals such as baths for copper etching. The concentration of the metal, particularly copper, in the solution Aqueous ammonia, will vary widely depending, for example, on the source of the solution. Where the solution is derived from the leaching of minerals, the concentration of the metal is often up to 75 g / 1 and more often from 10 to 40 g / 1. Where the solution is a waste stream metal concentrations are somewhat higher than those of mineral leaching, for example up to 150 g / 1, usually 75 to 130 g / 1. The process of the present invention can be carried out by contacting the composition of the extraction solvent with the aqueous ammoniacal solution. You can use, if desired, ambient or high temperatures such as up to 75 ° C. Often a «Aifaga ^ u *» ..i. »-temperature that is in the range of 15 to 60 ° C, and preferably 30 to 50 ° C. The aqueous solution and the extraction solvent are usually stirred together to maximize the inter-facile areas between the two solutions. The volumetric ratio of the extraction solvent to the aqueous solution is commonly in the range of 20: 1 to 1:20, and preferably in the range of 5: 1 to 1: 5. In many embodiments, to reduce the size of the plant and to maximize the use of the extraction solvent, the ratios of the volumes of the organic components to the aqueous ones are close to 1: 1, such as 1.5: 1 or less, and preferably 1.3: 1 or less. The molar ratio of the tohydroxy alcohol and the maximum with respect to the copper transferred is selected so that it is in the range of 2.7: 1 to 2: 1. Preferably, to achieve improved hydrolyzed properties, such as reduced viscosity and improved phase disengagement, the molar ratio of oxime to copper transferred is from 2.3: 1 to 2.0: 1. After contact with the solution t? tl? i m m A ^^^ & j ^^? In aqueous ammoniacal, the metal can be recovered from the extraction solvent by contact with a reextraction solution, aqueous, having a pH lower than that from which the metal was extracted. The aqueous reextraction solution, with lower pH, employed with the process according to the present invention, is usually acidic, and commonly has a pH of 2 or less, and preferably a pH of 1 or less, for example, a pH that is in the range of -1 to 0.5. The reextraction solution commonly comprises a mineral acid, particularly sulfuric acid, nitric acid or hydrochloric acid. In many embodiments, acid concentrations, particularly for sulfuric acid, are in the range of 130 to 200 g / 1 and preferably 150 to 180 g / 1. A low acid concentration can be used but at least one reextraction solution containing 4M chloride should be used as described in European Patent Application No. 93301095.1 (Publication No. 0 562 709 A2) or in the publication of International Application No. WO95 / 04835 (both of which are incorporated herein by reference). When the extracted metal is copper or zinc, the preferred reextraction solutions comprise respectively extracted or spent electrolyte from a cell for the electrolytic extraction of copper or zinc, typically comprising up to 80 g / 1 of copper or zinc, often more than 40 g / 1 of copper or zinc and preferably 50 to 70 g / 1 of copper or zinc, and up to 200 g / 1 of sulfuric acid, often more than 130 g / 1, and preferably 150 to 180 g / 1 of sulfuric acid. The volumetric ratio of the organic solution to the aqueous reextraction solution, In the process of the present invention, it is commonly selected to be such that transfer is achieved, per liter of reextraction solution, of up to 50 g / 1 of metal, especially copper, to the solution of reextraction from the organic solution. In many industrial electrolytic copper extraction processes, at least 10 g / 1, preferably 25 to 35 g / 1, are often transferred from the organic solution. especially about 30 g / 1 copper - _? * - £ - 'per liter of reextraction solution. Volumetric relationships are commonly used, from organic solution to aqueous solution, from 1: 2 to 15: 1 and preferably from 1: 1 to 5: 10: 1, especially less than 3: 1. A preferred embodiment of the present invention comprises a process for extracting a metal from an aqueous ammoniacal solution in which: in step 1, a water immiscible extraction solvent composition, comprising a tohydroxyar and Ice toxima and a thermodynamic modifier, first comes into contact with the aqueous ammoniacal solution that contains the metal, in step 2, the solvent extraction composition containing the metal complex and extraction solvent is separated from the aqueous ammoniacal solution; In step 3, the extraction solvent composition containing the metal complex and extraction solvent is contacted with an aqueous reextraction solution of a pH lower than that of the solution. ammonia, to effect the reextraction of the copper of the immiscible phase of water; in step 4, separate the composition of the extraction solvent without metal, from the aqueous solution of lower pH. The metal can be recovered from the aqueous reextraction solution by conventional methods, for example by electrolytic extraction. The invention is further illustrated, but not limited, by the following examples.

Examples 1 and 2 and comparison A A test was carried out in a miniature facility to investigate the performance of the different extraction solvent compositions, in the extraction of copper from a typical, ammoniacal, solution. copper. The process comprised two extraction stages, a washing step and a re-extraction step. In each stage, mixers-settlers were used, countercurrent, of 500 ml, stirred at 1,000 rpm. The stages of extraction were operated at a ratio of organic compound: aqueous compound (0: A) of 1.2: 1, and the washing and stripping steps were worked at a ratio of organic compound: aqueous compound (0: A) to 1: 1. The 5 residence times in each stage were approximately 3 minutes. The copper ammonia solution comprised 30 g / 1 copper, 45 g / 1 ammonia and 75 g / 1 sulphate. The wash solution was a sulfuric acid solution diluted with a pH of 2. The reextraction solution was an aqueous solution of copper sulfate comprising 30 g / 1 of copper and 180 g / 1 of sulfuric acid. Three different solvent compositions of extraction. In Example 1 the extraction solvent comprised 282 g / 1 oxime of 5- noni 1 - 2 -hi drox i ace tofenone and 11% w / w of isobutyrate of 2, 2, - tr ime ti 1- 1, 3-pent anodiol in the hydrocarbon solvent ORFOMMR SX7. At EXAMPLE 2 The extraction solvent comprised 247 g / 1 of 5-noni 1-2-hydroxy acetoacetate oxime and 9.7% w / w of isobutyrate of 2, 2, 4 - 1 r ime ti 1 - 1, 3-pent anodium 1 in the hydrocarbon solvent and ORFOMMR X7. In the comparison To the solvent of extraction comprised 282 g / 1 oxime of 5- nonyl-2-hydroxyl acetonide in the hydrocarbon solvent ORFOMMR SX7. During each of the tests, the copper content of the advancing electrolyte produced from the reaction solution was determined at periodic intervals and was used to calculate the percentage of copper recovery based on the copper content. of the aqueous ammonia solution. The percentages of copper recoveries achieved were as follows: Copper recovery test% E j empl o 1 100 (average of 7 terminations) E g p e 2 100 (average of 4 determinations) Comparison A 90.3 (average of 3 determinations) The results of Examples 1 and 2 clearly demonstrate the improved performance of the process according to the present invention, compared with the results for the comparison A (which is not in accordance with the present invention) in which a process which omits the thermodynamic modifier.

Examples 3, 4, 5, 6, 7 and 8, and Comparisons B and C In a separate test, extraction and reextraction isotherms were determined for the extraction solvent compositions. In each case the extraction solvent comprised 118 g / 1 (0.56 M) of 5-nonyl-2-hydroxy acetone oxime, the Comparison (B and C) compositions had no modifier and the compositions of the Examples contained 85 g / 1 of selected tridecanol modifier (Examples 3 and 6), isobutyrate of 2, 2, 4-t r ime t i 1- 1, 3-pent anodium 1 (Examples 4 and 7) or tributyl phosphate (Examples 5 and 8), in the hydrocarbon solvent ORFOMMR SX7. The charge isotherm was generated using a feed composition comprising 30 g / 1 copper and 45 g / 1 ammonia (2 to 3 g / 1 free ammonia) at 40 ° C. This was carried out by contacting the formulated reagent at different ratios of organic compound: aqueous compound (0: A), allowing the phases to reach equilibrium and then separating the phases and analyzing each phase with respect to the values of the metals. The reextraction isotherm was generated by contacting an organic phase charged with copper, with a reextraction acid composition comprising 35 g / 1 of copper and 150 g / 1 of sulfuric acid at 40 ° C. This was carried out at different ratios of organic compound: aqueous compound (0: A), allowing The phases will reach equilibrium and then separate them and analyze each phase with respect to the values of the metals. For Examples 3 and 6, the reextraction isotherm was measured at 0: A ratios of 2: 1, 1.5: 1, 1: 1, 1: 2, 1: 6, 1:10 and the extraction isotherm was measured at 0: A ratios of 1: 2, 1: 3, 1: 5, 1:10. For Examples 4 and 7 the reextraction isotherm was measured at 0: A ratios of 3: 1, 2: 1, 1.5: 1, 1: 1, 1: 2, 1: 4, 1:10 and the Extraction isotherm was measured at 0: A ratios of 1: 2, 1: 3, 1:10. For Examples 5 and 8, the reextraction isotherm was measured at 0: A ratios of 2: 1, 1.5: 1, 1: 1, 1: 2, 1: 5 and the extraction isotherm measured at ratios of 0: A of 1.5: 1, 1: 1, 1: 1.5, 1: 3. For the Comparisons B and C, the reextraction isotherm was measured at 0: A ratios of 3: 1, 2: 1, 1.5: 1, 1: 1, 1: 1.5, 1: 5 and the extraction isotherm was measured at ratios from 0: A of 1.5: 1, 1: 1, 1: 2, 1: 3. The expected recoveries were then predicted by iterative means using a McCabe-Thi construction, using the isotherm data generated from experimental data. The expected recoveries for a process of 2 extractions and one reextraction, at the 0: A ratios marked for the extraction and reextraction stages were: Modifier Relation O / A Extraction Reextraction Recovery Comparison - 1: 1 1: 1 51.45 B Example 3 DA 1: 1 1: 1 55.75 Example 4 TXIB 1: 1 1: 1 55.73 Table (continued) Modifier Relation O / A Extraction Reextraction Recovery Example 5 TBP 1: 1 1: 1 56.42 Comparison - 2.02: 1 1: 1 96.68 C Example 6 TDA 2.17: 1 1: 1 99.68 Example 7 TXIB 1.97: 1 1: 1 99.91 Example 8 TBP 2.14: 1 1: 1 98.33 TDA = Tridecanol TXIB = isobutyrate of 2,2, -Tri ethyl- 1,3-pentanediol TBP = Tributyl phosphate The results clearly demonstrate that an improved performance of the process, according to the present invention, can be achieved for a range of modifiers, compared to the results of comparisons B and C (which are not in accordance with the present invention) in which a process that omits the thermodynamic modifier was employed. . - 4j *? & * t * 4tot SL & mii & It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following: fifteen twenty

Claims (11)

1. A process for extracting a metal from an ammonia solution, in which an aqueous ammonia solution containing a dissolved metal, is contacted with an extraction solvent composition comprising an organic solvent immiscible with water and an extraction solvent. immiscible in water, whereby at least a fraction of the metal is extracted in the organic solution, characterized in that the composition of the extraction solvent comprises one or two hydroxides and a thermodynamic modifier.

2. A process according to claim 1, characterized in that the metal is copper, zinc, cobalt or nickel, and preferably is copper.

3. A process according to claim 1 or 2, characterized in that the tohydroxycarboxylic acid is selected from the class of compounds represented by the g | g ^^^ Fo rmul a 1) Formula (l wherein R 1 is an optionally substituted hydrocarbyl group, and R 2 is an optionally substituted ortho-hydroxyl group; and you come out of them.

4. A process according to claim 3, characterized in that the tohydroxycarbonate and Ice oxime has the general chemical formula: wherein R to R represent, each independently, H or an alkyl group, linear or branched, of 1 to 22 carbon atoms, ÍS ^? ^^^^^^ i m ^ < ^^ ¡^^^ j / ^^^ ¡^^^^^^^^^^^ preferably from 7 to 15 carbon atoms.

5. A process according to claim 4, characterized in that the The hydroxide is preferably an oxime of 5- (alkyl of 9 to 14 carbon atoms) -2- hydroxyacetylene, preferably oxime of 5-nonyl-2-hydroxyacetophenone.

6. A process in accordance with any of the preceding indications, characterized in that the thermodynamic modifier is an alkyl phenol, alcohol, ester, ether, polyether, carbonate, ketone, Nitrile, amide, carbamate, sulfoxide, or a salt of an amine or a quaternary ammonium compound.

7. A process according to any of claims 1 to 5, characterized in that the thermodynamic modifier is a mixture comprising a first compound selected from the group consisting of the alkyl phenols, alcohols, esters, ethers, polyethers, carbamates, WlM MilggfeB ^ yrt'foli '* g' ^ g »* 'fc * - ^' ^ '-g -« ^ aA ^ MgA «gfe¡gsgSS ^ g¡" -i ^ ,,, ^^^ - - « The compounds of the present invention are ketones, nitriles, amides, carbamates, sulfoxides, and salts of amines and quaternary ammonium compounds, and a second compound selected from the group consisting of alkanols having from 6 to 18 carbon atoms. , an alkyl phenol in which the alkyl group contains from 7 to 12 carbon atoms, and tributyl phosphate.

10. A process according to claim 6 or claim 7, characterized in that the modifier comprises a highly branched alkyl ester comprising from 10 to 30 carbon atoms, or a Highly branched alkanol comprising from 14 to 30 carbon atoms, or a trialkyl phosphate wherein the alkyl groups comprise from 4 to 14 carbon atoms.

9. A process for extracting copper from an ammonia solution, in which an aqueous ammoniacal solution containing dissolved copper, is contacted with an extraction solvent composition that 25 comprises an organic solvent immiscible in water and a water-immiscible extraction solvent, whereby at least a fraction of the copper is extracted into the organic solution, characterized in that the extraction solvent composition comprises from 25 to 35% w / w of 5- (oxime) alkyl from 8 to 14 carbon atoms) - 1-hydroxy acetophenone, from 5 to 15% w / w tridecanol, tributyl phosphate, or isobutyrate of 2, 2, 4 - 1 r ime ti 1- 1, 3-pent anodium 1 or 10 the benzoic acid ester thereof, and a hydrocarbon solvent immiscible in water.

10. An extraction solvent composition, characterized in that it comprises a 15 water-immiscible organic solvent, a water-insoluble hydroxide and a water insoluble thermodynamic modifier.

11. A composition according to claim 10, characterized in that the extracting solvent composition comprises from 25 to 35% w / w of 5-oxime (alkyl of 8 to 14 carbon atoms) - 2-hydroxylation f enone, from 5 to 15% w / w of tridecanol, tributyl phosphate, 25 or isobutyrate of 2, 2, 4-tr ime ti 1 - 1, 3 -pent anodium 1 - ^ Aifc * '^ --- .-------- i «iÉIMki ------- ÉI or the ester of benzoic acid thereof, and a hydrocarbon solvent immiscible in water. ífci ». 'L .ge ^^? ^? ^ A PROCESS FOR THE EXTRACTION OF METALS FROM AN AMMONIACAL SOLUTION SUMMARY OF THE INVENTION A process is provided for solvent extraction of metals, particularly copper, from aqueous ammonia solutions. The extraction solvent is an ortho-hydroxy-1-oximetry of Formula (1), Formula a (I) where R1 is a hydrocarbyl group, and R2 is a 15 group or rt o -hi drox i ar i 1 o and the extraction process is carried out in the presence of a kinetic modifier. Suitable thermodynamic modifiers that may be employed include alkylphenols, alcohols, esters, 20 ethers and polyethers, carbonates, ketones, nitriles, amides, carbamates, sulfoxides, and salts of amines and quaternary ammonium compounds. Preferred orthohydroxyaryl-oximes are oximes of 5- (alkyl of 9 to 25 14 carbon atoms) - 2-hydroxy acetone. The ^^ ¡¡¡¡¡¡¡¡? ^^^ ¿¡¡¡¡¡^ ^? ^ Gi? Preferred modifiers are highly branched alkyl esters comprising from 10 to 30 carbon atoms, or highly branched alkanols comprising from 14 to 30 carbon atoms, or chemical trioral phosphates wherein the alkyl groups comprise 4 to 14 carbon atoms. Extraction compositions comprising a ketoxime and a modifier are also provided.