Modified oxime extractant formulation

Abstract

A solvent extraction composition that is particularly useful for the extraction of metals from a solution containing the metals. The solvent extraction composition includes an orthohydroxyaryloxime extractant, at least one water immiscible organic solvent, and an effective amount of a substantially water insoluble equilibrium modifier. The equilibrium modifier includes at least one of an aliphatic, aromatic or araliphatic compound comprising three or more ester functional groups. A method for the solvent extraction of a metal such as copper from an aqueous solution using the solvent extraction composition is also provided.

1 . A solvent extraction composition, comprising:
 an orthohydroxyaryloxime extractant;   at least one water immiscible organic solvent; and   an effective amount of a substantially water insoluble equilibrium modifier selected from the group consisting of aliphatic, aromatic, and araliphatic compounds, the equilibrium modifier comprising three or more ester functional groups.   
     
     
         2 . The composition recited in  claim 1 , wherein the orthohydroxyaryloxime extractant comprises a compound according to Formula (1): 
       
         
           
           
               
               
           
         
         and salts, tautomers or metal complexes thereof, wherein R 1  is an optionally substituted C 1 -C 20  hydrocarbyl group and R 2  is an optionally substituted C 6 -C 20  orthohydroxyaryl group. 
       
     
     
         3 . The composition recited in  claim 1 , wherein the orthohydroxyaryloxime extractant comprises a compound according to Formula (2): 
       
         
           
           
               
               
           
         
         and salts, tautomers or metal complexes thereof, wherein R 3  is an optionally substituted C 6 -C 20  orthohydroxyaryl group. 
       
     
     
         4 . The composition recited in  claim 1 , wherein the orthohydroxyaryloxime extractant comprises a compound selected from the group consisting of: 5-(C 8  to C 14  alkyl)-2-hydroxyacetophenone oximes, 5-(C 8  to C 14  alkyl)-2-hydroxybenzaldoximes, and mixtures thereof. 
     
     
         5 . The composition recited in  claim 1 , wherein the equilibrium modifier comprises up to 80 carbon atoms. 
     
     
         6 . The composition recited in  claim 1 , wherein the ester functional groups are selected from butyrates, propanates and mixtures thereof. 
     
     
         7 . The composition recited in  claim 1 , wherein the equilibrium modifier is selected from the group consisting of trihydroxy alcohols, tetrahydroxy alcohols, polyhydroxy compounds, tricarboxylic acids, tetracarboxylic acids and mixtures thereof. 
     
     
         8 . The composition recited in  claim 1 , wherein the equilibrium modifier comprises a trihydroxy alcohol. 
     
     
         9 . The composition recited in  claim 8 , wherein the trihydroxy alcohol comprises up to 20 carbon atoms and an optionally substituted monocarboxylic acid containing 1-20 carbon atoms. 
     
     
         10 . The composition recited in  claim 8 , wherein the trihydroxy alcohol is selected from the group consisting of: glycerol; 1,1,1-tris(hydroxymethyl)propane; 1,1,1-tris(hydroxymethyl)ethane; 1,2,6-hexanetriol; 3-methyl-1,3,5-pentanetriol; 1,3,5-triazine-2,4,6-triol; 1,2,4-butanetriol; 1,3,5-trihydroxybenzene; pyrogallol; and isomers of these compounds. 
     
     
         11 . The composition recited in  claim 1 , wherein the equilibrium modifier comprises a tetrahydroxy alcohol. 
     
     
         12 . The composition recited in  claim 11 , wherein the tetrahydroxy alcohol comprises up to 20 carbon atoms and a optionally substituted monocarboxylic acid containing 1-20 carbon atoms. 
     
     
         13 . The composition recited in  claim 11 , wherein the tetrahydroxy alcohol is selected from the group consisting of pentaerythritol and erythritol. 
     
     
         14 . The composition recited in  claim 11 , wherein the equilibrium modifier is pentaerythritol tetrapropionate. 
     
     
         15 . The composition recited in  claim 1 , wherein the equilibrium modifier comprises a polyhydroxy compound. 
     
     
         16 . The composition recited in  claim 15 , wherein the polyhydroxy compound comprises 5 or more alcohol functional groups having up to 40 carbon atoms and an optionally substituted monocarboxylic acid containing 1-20 carbon atoms. 
     
     
         17 . The composition recited in  claim 15 , wherein the polyhydroxy compound is selected from the group consisting of dipentaerythritol, carbohydrates and carbohydrate polyols. 
     
     
         18 . The composition recited in  claim 17 , wherein the polyhyroxy compound is selected from the group consisting of monosaccharide, disaccharide, oligosaccharide and polysaccharide. 
     
     
         19 . The composition recited in  claim 15 , wherein the equilibrium modifier comprises a mixture of at least one carbohydrate and at least one carbohydrate polyol, mannitol, sorbitol, xylitol, lactitol, maltitol, erythritol, isomalt, 1,6-GPS, 1,1-GPS, 1,1-GPM, hydrogenated starch hydrolyzate, hydrogenated glucose syrup and mixtures thereof. 
     
     
         20 . The composition recited in  claim 19 , wherein the equilibrium modifier comprises a carbohydrate polyol selected from the group consisting of a C 5 -polyol, a C 6 -polyol and mixtures thereof. 
     
     
         21 . The composition recited in  claim 19 , wherein the equilibrium modifier comprises a disaccharide polyol. 
     
     
         22 . The composition recited in  claim 21 , wherein the disaccharide polyol is selected from the group consisting of arabitol, xylitol, ribitol, inositol, mannitol, sorbitol, galactitol, and mixtures thereof. 
     
     
         23 . The composition recited in  claim 1 , wherein the equilibrium modifier comprises a tricarboxylic acid. 
     
     
         24 . The composition recited in  claim 23 , wherein the tricarboxylic acid comprises up to 20 carbon atoms and a monohydroxy alcohol containing 1-20 carbon atoms. 
     
     
         25 . The composition recited in  claim 23 , wherein the tricarboxylic acid is selected from the group consisting of: benzene-1,2,4-tricarboxylic acid; trimesic acid; tricarballylic acid; aconitic acid; and mixtures thereof. 
     
     
         26 . The composition recited in  claim 1 , wherein the equilibrium modifier comprises a tetracarboxylic acid. 
     
     
         27 . The composition recited in  claim 26 , wherein the tetracarboxylic acid comprises up to 20 carbon atoms and a monohydroxy alcohol containing 1-20 carbon atoms. 
     
     
         28 . The composition recited in  claim 26 , wherein the tetracarboxylic acid is 1,2,4,5-benzenetetracarboxylic acid. 
     
     
         29 . The composition recited in  claim 1 , wherein the equilibrium modifier compound comprises alcohol functional groups that have been ethoxylated, propoxyated, or ethoxylated and propoxylated. 
     
     
         30 . The composition recited in  claim 1 , wherein the equilibrium modifier has a ratio of carbon atoms to ester functional groups of from about 7:1 to about 3:1. 
     
     
         31 . The composition recited in  claim 1 , wherein the equilibrium modifier has a ratio of carbon atoms to ester functional groups of from about 6:1 to about 4:1. 
     
     
         32 . The composition recited in  claim 1 , wherein the equilibrium modifier comprises at least one ether or alcohol functional group and has a ratio of carbon atoms to oxygen atoms of from about 3.5:1 to about 2:1. 
     
     
         33 . The composition recited in  claim 1 , wherein the molar ratio of the orthohydroxyaryloxime extractant to the equilibrium modifier is at least about 0.02. 
     
     
         34 . The composition recited in  claim 1 , wherein the molar ratio of the orthohydroxyaryloxime extractant to the equilibrium modifier is not greater than about 1.5. 
     
     
         35 . The composition recited in  claim 1 , wherein the composition comprises from about 1 wt. % to about 70 wt. % of the orthohydroxyaryloxime extractant. 
     
     
         36 . The composition recited in  claim 1 , wherein the composition comprises at least about 5 wt. % and not greater than about 30 wt. % of the orthohydroxyaryloxime extractant. 
     
     
         37 . The composition recited in  claim 1 , wherein the orthohydroxyaryloxime extractant comprises a mixture of aldoxime and ketoxime, and wherein the weight ratio of the aldoxime:ketoxime is from about 90:10 to about 30:70. 
     
     
         38 . The composition recited in  claim 1 , wherein the organic solvent has an aromatic hydrocarbon content of not greater than about 30 wt. %. 
     
     
         39 . The composition recited in  claim 1 , wherein the organic solvent has an aromatic hydrocarbon content of not greater than about 23 wt. %. 
     
     
         40 . The composition recited in  claim 1 , wherein the composition comprises from about 30 wt. % to about 95 wt. % of the organic solvent. 
     
     
         41 . The composition recited in  claim 1 , further comprising an anti-degradation additive. 
     
     
         42 . The composition recited in  claim 41 , wherein the composition comprises from about 0.1 wt. % to about 10 wt. % of the anti-degradation additive. 
     
     
         43 . A process for recovering a metal from an aqueous solution, comprising the steps of:
 contacting an aqueous solution containing a metal with a solvent extraction composition recited in  claim 1 , thereby forming a metal-solvent extractant complex in a water-immiscible phase; and   contacting the metal-solvent extractant complex in the water-immiscible phase with an aqueous acidic strip solution, thereby stripping the metal from the water-immiscible phase.   
     
     
         44 . The process recited in  claim 43 , wherein the aqueous solution is an acidic solution. 
     
     
         45 . The process recited in  claim 43 , wherein the metal is chosen from the group consisting of copper, iron, cobalt, nickel, manganese, zinc and mixtures thereof. 
     
     
         46 . The process recited in  claim 43 , wherein the volume ratio of solvent extractant to aqueous acidic solution is from about 20:1 to about 1:20. 
     
     
         47 . The process recited in  claim 43 , wherein the volume ratio of solvent extractant to aqueous acidic solution is from about 5:1 to about 1:5. 
     
     
         48 . The process recited in  claim 43 , further comprising the step of recycling the solvent extractant or the aqueous acidic solution. 
     
     
         49 . The process recited in  claim 43 , wherein the aqueous acidic strip solution is a mineral acid selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid and mixtures thereof.