China Nonferrous Metallurgy

The method of preparing crude cobalt hydroxide by using active magnesium oxide slurry to precipitate cobalt ions in the cobalt raffinate has the problem of unstable cobalt product quality when using the low-cobalt solution as raw material. In response to this problem, this paper investigated the effects of magnesium oxide mass concentration, reaction temperature, end pH, cobalt and copper ion concentration, washing liquid-solid ratio on the cobalt content and magnesium content in the cobalt hydroxide. The results show that it has little effect on the quality of crude cobalt hydroxide when the mass concentration of active magnesium oxide is 2%~10%. It will improve the efficiency of preparation of crude cobalt when the temperature and end pH reach 45℃ and 7.3, respectively. In addition, the higher concentration of cobalt ions and the lower concentration of copper ions are in the solution, the more cobalt grade is in the crude cobalt hydroxide. Industrial production shows that crude cobalt hydroxide which contains higher magnesium can reach the industry second-class product standards after being washed with water.