China Nonferrous Metallurgy

Raw materials for zinc smelting used by Bayannaoer Zijin Nonferrous Metal Co., Ltd. are characterized by a high content of Fe, Co and S and a low content of Zn. Supernatant produced from neutral leaching contains a high content of cobalt up to 50~100mg/L. In order to control the cost, the company makes an exploration of the cobalt removal process by antimony salt, β-naphthol and new reagent and draws a conclusion as follows. During the practical production, cobalt removal and purification process by antimony salt is characterized by a frequent fluctuation of cobalt content, unstable cobalt removal, larger consumption of zinc powder and great difficulty in on-site operation. Hence it is suitable for zinc sulfate purification process with a low cobalt content Cobalt removal and purification process with naphthol shows a good effect, with stable system and simple on-site operation, but it only works for cobalt removal rather than other impurity elements. When impurity elements such as Fe, Ni, As and Ge in the zinc sulfate solution are at a high content, it is still necessary to take other measures for removal. Cobalt removal process with new reagent can remove miscellaneous impurities, which not only yields a good cobalt removal result but also works well for other impurity elements in the zinc sulfate solution with simple on-site operation and continuous and steady production. Among three purification processes, the last one features the minimum unit consumption (cathode zinc per ton) of zinc powder and processing cost.