Patent ID: 8609063

Claim:
A method of reducing degradation of a hydrometallurgical solvent extraction composition comprising an orthohydroxyaryloxime compound, or salts, tautomers or metal complexes thereof, the method comprising: adding to the solvent extraction composition, and/or a solvent extraction circuit containing said solvent extraction composition, an anti-degradation agent chosen from a member selected from the group consisting of: i) a phenol compound substituted with a member selected from the group consisting of 2 t-butyl groups; from 1 to 2 t-butyl groups and a C 1 -C 4 alkyl group; from 1 to 3 alkaryl groups; and a cumyl group; ii) a catechol compound substituted with a solubilizing group chosen from a member selected from the group consisting of an optionally substituted C 6 -C 20 alkyl; and an optionally substituted C 6 -C 20 aryl; iii) a resorcinol compound substituted with a solubilizing group chosen from a member selected from the group consisting of an optionally substituted C 6 -C 20 alkyl; and an optionally substituted C 6 -C 20 aryl; and iv) mixtures of (i)-(iii), thereby stabilizing the orthohydroxyaryloxime compound or salts, tautomers or metal complexes thereof, and reducing degradation of the solvent extraction composition.