Process for extracting metals

摘要

A process for extracting metal values especially zinc values from aqueous solutions of metal salts which comprises contacting the aqueous solution with an organic phase comprising a compound of the formula: <IMAGE> I wherein each of R1, R2, R3 and R4, independently, represents a substituted hydrocarbyl or hydrocarbyloxy group or R1 and R2 together with the attached phosphorus atom and/or R3 and R4 together with the attached phosphorus atom form a 5- to 8-membered heterocyclic ring.