RECOVERY OF COBALT FROM POLYMETALLIC CONCENTRATES-NICO DEPOSIT,NWT, CANADA - PILOT PLANT RESULTS

摘要

This paper provides an overview of the NICO deposit process development work throughout the past decade, with emphasis on the latest results on the recovery of cobalt. The results presented in the paper were produced by an integrated pilot plant carried out in 2008. The NICO "IOCG" (iron oxide-copper-gold) type deposit is located in the Mazenod Lake district near the Snare hydroelectric complex, approximately 160 km northwest of Yellowknife, Northwest Territories, Canada. Cobalt is recovered by flotation into a concentrate wherefrom it is leached by pressure oxidation followed by solution purification (involving copper solvent extraction and iron removal), ion exchange, precipitation and electrowinning. The pressure oxidation occurs with selective rejection of arsenic and iron allowing environmentally acceptable tailings disposal as ferric arsenate. The process relies entirely on commercially proven unit operations and equipment and the integrated pilot exercise proved its technical feasibility. This paper summarizes the results of the purification of the cobalt solution and its electrowinning as cathode.