Refining of noble group metals

Abstract

This invention relates to the separation and purification of platinum group metals and, in particular to the separation of mixtures of rhodium, platinum and irridium. According to one specific form of the invention, the platinum, rhodium and iridium are present as salts in aqueous solution and the separation and purification is accomplished by A. adjusting the pH, as necessary, to provide an acidic solution; B. contacting the acidic solution with an oxidizing agent sufficient to effect the oxidation of all irridium to Ir(IV); c. contacting the oxidized solution with a nitrogen-containing organic compound selected from the group consisting of secondary amines, tertiary amines and quaternary ammonium compounds; and D. removing from contact with the oxidized solution an organic phase containing substantially all of the platinum and iridium present in association with the nitrogen-containing organic compound used in step (c).

Dependencies are inferred from the claim text.