Patent ID: 6048506
Filing Date: 2000-04-11
Classification: C22B,Y02P

Abstract:
A process for selectively separating unwanted ferric iron and zinc impurities from a cobalt sulphate solution containing said iron and zinc impurities, as well as at least one of chloride and nitrate ion impurities, said process including the steps of:(i) contacting the cobalt sulphate solution with bis(2,4,4-trimethylpentyl)phosphinic acid in aliphatic kerosene at an initial pH of less than 2.8 to selectively extract the majority of the unwanted ferric iron impurities from the cobalt sulphate solution; and(ii) raising the pH of the solution to about 3.5 while maintaining contact with the bis(2,4,4-trimethylpentyl)phosphinic acid in aliphatic kerosene in order to extract zinc impurities and any remaining ferric iron impurities from the cobalt sulphate solution.