Separation of cobalt from zinc sulfate solutions by synthetic cation exchange resins

The purpose of the present research is primarily to investigate the possibility of the separation and recovery of cobalt from zinc sulfate solutions by means of cation exchange resins. It is thought that such an investigation, seemingly of academic interest, might throw some light on determining the possibility of processing some industrial solutions containing both cobalt and zinc. Cobalt, for instance, has been well known as one of the most detrimental impurities in zinc electrolytic solutions. In spite of various purification treatments, small amounts of cobalt are often present in the electrolytic solution, causing a reduction in current efficiency and the production of irregular cathodic zinc. The question was whether an efficient separation of the cobalt could be obtained by the use of cation exchange resins. As shown by the experiments presented later, the carboxylic acid resin does bring about considerable separation of cobalt from zinc when a proper elutriant is employed. However, since zinc, rather than cobalt, is preferentially retained by the resin, this process does not offer a practical method for purifying the zinc electrolytic solution --Introduction, page 2-3