BACKGROUNDChanges to the process flowsheet and increasing zinc content of the feed materials to the Anglo American Platinum Rustenburg Base Metals Refinery circuit resulted in increasing deportment of zinc to the nickel product and necessitated a dedicated zinc-removal circuit to ensure continued consistent quality of the nickel cathode. RESULTSThe development of an ion-exchange process for the removal of 0.03gL(-1) Zn from a stream containing 70gL(-1) Ni, 0.2gL(-1) Co is described. Batch testwork compared the di(2-ethylhexyl)phosphoric acid-impregnated resin, Lewatit VP OC 1026, with the aminophosphonic acid resin, Purolite S950, and identified the most suitable resin for this application with respect to loading capacity and selectivity. Continuous column testwork then allowed determination of the mass transfer zone length, on which the full-scale plant design was based. CONCLUSIONA plant treating 15m(3)h(-1) was installed for removal of zinc from the selected process stream using Lewatit VP OC 1026. The zinc content of the nickel cathode was reduced by 40% following commissioning of this ion-exchange plant, allowing the target product specification to be consistently met. (c) 2014 Society of Chemical Industry.