IMPROVEMENT IN THE PROCESS OF RECOVERY OF METALS

摘要

An improved process for the extraction of a metal from an aqueous ammoniacal solution comprising: (i) contacting the aqueous ammoniacal solution with an extraction reagent comprised of a water insoluble extractant for the metal, to provide an organic phase, now containing metal values, and an aqueous phase from which metal values have been extracted; (ii) contacting the organic phase with an aqueous stripping solution to provide an aqueous strip phase, now containing metal values, and an organic phase from which metal values have been stripped; and (iii) recovering the metal values from the aqueous stripping solution; the improvement wherein (a) the extraction reagent contains an ammonia antagonist having only hydrogen bond acceptor properties; (b) the stripping solution is an aqueous highly acidic solution; and (c) the organic phase is washed with a weakly acidic aqueous solution prior to stripping with the highly acidic aqueous stripping solution. The extractant is preferably an oxime extractant, either a ketoxime or an aldoxime. The preferred hydrocarbon solvent is kerosene and the preferred antagonist is 2,2,4-trimethylpentane-1,3-diol diisobutyrate.