PRODUCTION OF HIGH PURITY COBALT SOLUTION

摘要

PROBLEM TO BE SOLVED: To provide a method for producing a high purity cobalt solution by efficiently removing various impurities from a cobalt solution. SOLUTION: This method is composed of a 1st process for precipitating iron, manganese and a part of copper by keeping the cobalt solution containing iron, manganese, zinc, calcium and copper as the impurities to >=600 mV oxidation reduction potential in the standard of a Ag/AgCl electrode while oxidizing to be pH <=4.0 and if necessary, further keeping to >=600 mV oxidation reduction potential in the standard of the Ag/AgCl electrode and pH <=4.0 to precipitate the almost of all copper and neutralizing to remove the generated precipitate, a 2nd process for solvent-extracting zinc and calcium in the cobalt solution and a trace quantity of the impurities remaining in the 1st process with an alkyl phosphoric acid, a 3rd process for cleaning an organic phase containing the resultant impurities and a part of cobalt with an aq. solution adjusted in pH and recovering cobalt co-extracted with the impurities in the organic phase and a 4th process for treating the resultant organic phase with a mineral acid to strip the impurities remaining in the organic phase to regenerate the organic phase.