Abstract:The effects of neutralizer dosage, time and Co/Mn ratio on the precipitation of cobalt and impurities in a low grade cobalt solution were investigated in a one-stage precipitation process using active magnesium oxide as neutralizer. The results showed that on the condition of MgO dosage of 1.20 times, 8 h, and the Co/Mn ratio of 5.95, the precipitation rates of Co and Mn were 88.30% and 44.80%, respectively. The content of Co in cobalt hydroxide products was 36.85%, and the impurities Mg and Mn were 2.15% and 2.73%, respectively. Based on the optimal conditions of one-stage cobalt precipitation, two-stage cobalt precipitation cycle tests were conducted. The results showed that the overall precipitation rates of Co and Mn were 96.63% and 34.67%, respectively, on the condition of MgO dosage of 1.20 times, Co/Mn ratio of 5.95, 8 h in the first stage and 3 h in the second stage. In cobalt hydroxide precipitation, Co was 37.16%, and impurities Mg and Mn were 2.48% and 2.56%, respectively. Compared with the one-stage cobalt precipitation, the two-stage had higher cobalt precipitation rate and lower impurity manganese precipitation rate. The two-stage cobalt precipitation process was suitable for treating the low cobalt solution.