Indium recovery by supported liquid membrane with strip dispersion

Abstract

The present invention provides a process for the removal and recovery of indium from waste waters and process streams. The process of the present invention utilizes a combination of a supported liquid membrane (SLM) and a strip dispersion to improve extraction of indium while increasing membrane stability and decreasing processing costs. This novel process selectively removes indium from the feed stream, provides the increased flexibility of aqueous strip/organic volume ratio, and produces a concentrated strip solution of indium.

1 . A combined supported liquid membrane (SLM)/strip dispersion process for the removal and recovery of indium from a feed solution containing the indium comprising
 (1) treating a feed solution containing indium on one side of the SLM embedded in a microporous support material to remove the indium by the use of a strip dispersion on the other side of the SLM, the strip dispersion being formed by dispersing an aqueous strip solution in an organic liquid comprising an extractant using a mixer; and   (2) allowing the strip dispersion or a part of the strip dispersion to separate into two phases, the organic liquid phase and the aqueous strip solution phase containing a concentrated indium solution.   
     
     
         2 . The process of  claim 1 , wherein the feed solution is treated to remove indium to a concentration of 5 parts per million (ppm) or lower. 
     
     
         3 . The process of  claim 1 , wherein the aqueous strip solution of the strip dispersion comprises an acid. 
     
     
         4 . The process of  claim 3 , wherein the acid is selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, and mixtures thereof. 
     
     
         5 . The process of  claim 1 , wherein the organic liquid of the strip dispersion further comprises a modifier in a hydrocarbon solvent or mixture. 
     
     
         6 . The process of  claim 1 , wherein the organic liquid of the strip dispersion comprises about 2 volume % to about 100 volume % extractant and about 0 volume % to about 20 volume % modifier in a hydrocarbon solvent or mixture. 
     
     
         7 . The process of  claim 6 , wherein the organic liquid of the strip dispersion comprises about 5 volume % to about 40 volume % extractant and about 1 volume % to about 10 volume % modifier in a hydrocarbon solvent or mixture. 
     
     
         8 . The process of  claim 5 , wherein the modifier is selected from the group consisting of alcohols, nitrophenyl alkyl ethers, trialkyl phosphates, and mixtures thereof. 
     
     
         9 . The process of  claim 8  wherein the alcohol is selected from the group consisting of hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadacanol, octadecanol, and mixtures thereof. 
     
     
         10 . The process of  claim 8  wherein the nitrophenyl alkyl ether is selected from the group consisting of o-nitrophenyl octyl ether (o-NPOE), o-nitrophenyl heptyl ether, o-nitrophenyl hexyl ether, o-nitrophenyl pentyl ether (o-NPPE), o-nitrophenyl butyl ether, o-nitrophenyl propyl ether, and mixtures thereof. 
     
     
         11 . The process of  claim 8 , wherein the trialkyl phosphate is selected from the group consisting of tributyl phosphate, tris(2-ethylhexyl)phosphate, and mixtures thereof. 
     
     
         12 . The process of  claim 5 , wherein the hydrocarbon solvent is selected from a group consisting of n-decane; n-undecane; n-dodecane; n-tridecane; n-tetradecane; isodecane; isoundecane; isododecane; isotridecane; isotetradecane; isoparaffinic hydrocarbon solvent having a flash point of 92° C., a boiling point of 254° C., a viscosity of 3 cp at 25° C., and a density of 0.791 g/ml at 15.6° C.; and mixtures thereof. 
     
     
         13 . The process of  claim 1 , wherein the microporous support material is selected from the group consisting of polypropylene, polytetrafluoroethylene, polyethylene, polysulfone, polyethersulfone, polyetheretherketone, polyimide, polyamide, polyaramide, and mixtures thereof. 
     
     
         14 . The process of  claim 1 , wherein the microporous support material is polypropylene. 
     
     
         15 . The process of  claim 1 , wherein the extractant comprises a dialkyl phosphoric acid. 
     
     
         16 . The process of  claim 15 , wherein the dialkyl group of the dialkyl phosphoric acid is paraffinic (saturated) and has from 6 to 26 carbon atoms. 
     
     
         17 . The process of  claim 15 , wherein the dialkyl phosphoric acid is selected from the group consisting of di(2-ethyl-hexyl)phosphoric acid (D2EHPA), di(2-butyl-octyl)phosphoric acid, di(2-hexyl-decyl)phosphoric acid, di(2-octyl-decyl/2-hexyl-dodecyl)phosphoric acid, di(2-octyl-dodecyl)phosphoric acid, di(hexyl)phosphoric acid, di(heptyl)phosphoric acid, di(octyl)phosphoric acid, di(nonyl)phosphoric acid, di(decyl)phosphoric acid, di(undecyl)phosphoric acid, di(dodecyl)phosphoric acid, di(tridecyl)phosphoric acid, di(tetradecyl)phosphoric acid, di(pentadecyl)phosphoric acid, di(hexadecyl)phosphoric acid, di(heptadecyl)phosphoric acid, di(octadecyl)phosphoric acid, di(nonadecyl)phosphoric acid, di(decadecyl)phosphoric acid, di(undecadecyl)phosphoric acid, di(dodecadecyl)phosphoric acid, di(tridecadecyl)phosphoric acid, di(tetrdecadecyl)phosphoric acid, di(pentadadecyl)phosphoric acid, di(hexadecadecyl)phosphoric acid, and mixtures thereof. 
     
     
         18 . The process of  claim 15  wherein the dialkyl phosphoric acid is di(2-ethyl-hexyl)phosphoric acid (D2EHPA). 
     
     
         19 . The process of  claim 1  wherein the extractant comprises an alkyl phenylphosphonic acid. 
     
     
         20 . The process of  claim 19  wherein the alkyl group of the alkyl phenylphosphonic acid is paraffinic (saturated) and has from 6 to 26 carbon atoms. 
     
     
         21 . The process of  claim 19  wherein the alkyl phenylphosphonic acid is selected from the group consisting of 2-butyl-1-octyl phenylphosphonic acid (BOPPA), 2-hexyl-1-decyl phenylphosphonic acid, 2-octyl-1-decyl/2-hexyl-1-dodecyl phenylphosphonic acid, 2-octyl-1-dodecyl phenylphosphonic acid, hexyl phenylphosphonic acid, heptyl phenylphosphonic acid, octyl phenylphosphonic acid, nonyl phenylphosphonic acid, decyl phenylphosphonic acid, undecyl phenylphosphonic acid, dodecyl phenylphosphonic acid, tridecyl phenylphosphonic acid, tetradecyl phenylphosphonic acid, pentadecyl phenylphosphonic acid, hexadecyl phenylphosphonic acid, heptadecyl phenylphosphonic acid, octadecyl phenylphosphonic acid, nonadecyl phenylphosphonic acid, decadecyl phenylphosphonic acid, undecadecyl phenylphosphonic acid, dodecadecyl phenylphosphonic acid, tridecadecyl phenylphosphonic acid, tetrdecadecyl phenylphosphonic acid, pentadadecyl phenylphosphonic acid, hexadecadecyl phenylphosphonic acid, and mixtures thereof. 
     
     
         22 . The process of  claim 19  wherein the alkyl phenylphosphonic acid is 2-butyl-1-octyl phenylphosphonic acid (BOPPA).