Process for producing cobalt compound and process for producing solution of cobalt sulfate

摘要

PROBLEM TO BE SOLVED: To efficiently remove ammonium and nitric acid radicals in a cobalt compd. up to a low concn. with low energy by roasting the cobalt compd. contg. ammonium nitric acid ions as impurities in an inert gaseous atmosphere or together with a reducing agent and to efficiently prepare a cobalt sulfate soln. SOLUTION: Sulfuric acid and at least one reducing agent selected from methanol, ethanol, sodium sulfite and gaseous SO2 are dissolved in a cobalt compd.-contg. soln. at >=50 deg.C. Gaseous SO2 used as the reducing agent is added so as to attain 300-700 mV oxidation-reduction potential of the cobalt compd.- contg. soln.