PRODUCTION OF HIGH-PURITY COBALT

摘要

PROBLEM TO BE SOLVED: To stably obtain high-purity Co at a low cost by electrolytically extracting cobalt from an electrolyte contg. cobalt sulfate, regulating the electrolyte tailings with cobalt hydroxide, removing the insoluble impurities to purify it and recycling the purified electrolyte tailings. SOLUTION: Co is electrolytically extracted from an electrolyte contg. CoSO4 . The electrolyte tailings are regulated to the same performance as the original injection soln. contg. 50-90 g/L Co and kept at pH 2-4 by the use of Co(OH)2 . The Co(OH)2 is preferably prepared by adding aq. ammonia to an aq. CoSO4 soln. and blowing ammonia gas into the soln. Further, the insoluble impurities contg. Ni, Fe, Mn, Al, Cu, Cd, etc., formed in the electrolysis and regulation are filtered off from the tailings. Consequently, the highly refined electrolyte tailings are recycled as an electrolyte. A high-purity >=5 N Co of a sputtering target material is efficiently obtained by such a simple process.