Selectively stripping iron ions from an organic solvent

Claim 2

A process for selectively stripping iron ions into an aqueous phase from an organic solvent (A), which process comprises bringing an organic solvent (A) containing one or more compounds selected from the group consisting of alkyl phosphoric acid, alkyl--aryl phosphoric acid, alkyl thio phosphoric acid and alkyl-aryl thio phosphoric acid together with a petroleum hydrocarbon as a diluent and iron and zinc ions into contact with an aqueous solution containing NH 4 + and F - ions.

Claim 3

A process according to claim 1 in which the organic solvent (A) containing the iron and zinc ions has been obtained by bringing the organic solvent into contact with an aqueous phase containing mainly iron and zinc ions.

Claim 4

A process for treating solid raw material containing mainly iron and zinc, which process comprises: (a) a 1st step of dissolving solid raw material containing mainly iron and zinc with acid; (a') if dissolved iron from the 1st step is not already present as Fe 3+ ions, converting dissolved iron to Fe3+ ions; (b) a 2nd step of selectively extracting Fe 3+ ions from the resultant aqueous solution by contacting the solution with an organic solvent (A); (c) a 3rd step of regenerating the organic solvent (A) by contacting the organic solvent (A) containing Fe 3+ ions from the 2nd step with an aqueous solution containing NH 4 + and F ions; and (d) a 4th step of recycling aqueous solution resulting from the 2nd step back to the 1st step.

Claim 5

A process for treating solid raw material containing mainly iron and zinc, which process comprises: (a) a 1st step of dissolving solid raw material containing mainly iron and zinc with acid; (a') if dissolved iron from the 1st step is not already present as Fe 3+ ions, converting dissolved iron to Fe3+ ions; (b) a 2nd step of selectively extracting Fe 3+ ions from the resultant aqueous solution by contacting the solution with an organic solvent (A); (c) a 3rd step of regenerating the organic solvent (A) by contacting the organic solvent (A) containing Fe 3+ ions from the 2nd step with an aqueous solution containing NH 4 + and F ions; and (d) a 4th step of recycling aqueous solution resulting from the 2nd step back to the 1st step.

Claim 6

A process according to claim 3 wherein the acid used in the 1st step is an aqueous solution containing one or more acids selected from the group consisting of HNO 3 , H 2 SO 4 and HC1.

Claim 7

A process for recovering zinc in the form of metallic zinc, zinc oxide, zinc chloride, zinc sulphate or zinc nitrate from a solid raw material containing zinc, which process comprises: (a) a 1st step of leaching the solid raw material with an organic solvent (B) comprising (i) one or more compounds selected from the group consisting of carboxylic acids together with (ii) a petroleum hydrocarbon as a diluent; (b) a 2nd step of recovering organic solvent (B) remaining in the leached residue from the 1st step by dissolution with an aqueous solution containing one or more acids selected from the group consisting of HC1, H 2 S0 4 and HN0 3 ; (b') if dissolved iron in the aqueous solution which results from the 2nd step is not already present as Fe 3+ ions, converting dissolved iron to Fe 3+ ions; (c) a 3rd step of selectively extracting Fe 3+ ions from the aqueous solution which contains them and which contains'mainly iron and zinc ions by contacting the solution with an organic solvent (A); and (d) a 4th step of regenerating organic solvent (B) from the organic solvent (B) containing zinc which results from the 1st step, by contacting the organic solvent (B) containing zinc with an aqueous solution containing HCl , H2S04 , HN03 or NH 4 + and F - ions.

Claim 8

A process for recovering zinc in the form of metallic zinc, zinc oxide, zinc chloride, zinc sulphate or zinc nitrate from a solid raw material containing zinc, which process comprises: (a) a 1st step of leaching the solid raw material with an organic solvent (B) comprising (i) one or more compounds selected from the group consisting of carboxylic acids together with (ii) a petroleum hydrocarbon as a diluent; (b) a 2nd step of recovering organic solvent (B) remaining in the leached residue from the 1st step by dissolution with an aqueous solution containing one or more acids selected from the group consisting of HC1, H 2 S0 4 and HN0 3 ; (b') if dissolved iron in the aqueous solution which results from the 2nd step is not already present as Fe 3+ ions, converting dissolved iron to Fe 3+ ions; (c) a 3rd step of selectively extracting Fe 3+ ions from the aqueous solution which contains them and which contains'mainly iron and zinc ions by contacting the solution with an organic solvent (A); and (d) a 4th step of regenerating organic solvent (B) from the organic solvent (B) containing zinc which results from the 1st step, by contacting the organic solvent (B) containing zinc with an aqueous solution containing HCl , H2S04 , HN03 or NH 4 + and F - ions.

Claim 9

A process according to claim 5 wherein an aqueous solution containing NH 4 + and F - ions is employed in the 4th step and the resulting zinc salt is converted to metaalic zinc or zinc oxide.

Claim 10

A process according to claim 5 or 6 wherein the organic solvent (B) contains one or more compounds containing the hydroxime group in the range of from 0.1 to 15 volume %.

Claim 11

A process according to any one of claims 5 - 7 wherein lead and cadmium are coextracted with the zinc into the organic solvent (B) in the 1st step, and lead and cadmium are then selectively removed from the organic solvent (B) by contact with an aqueous solution of pH under 5.

Claim 12

A process according to any one of claims 5 - 8 wherein organic solvent (A) is regenerated from the organic solvent (A) containing Fe ions by contacting the organic solvent (A) containing Fe ions with an aqueous solution containing NH 4 + and F - ions.

Claim 13

A process according to any one of claims 5 - 9 wherein the solid raw material contains zinc oxide.