Abstract:In order to extract nickel and cobalt from crude nickel cobalt hydroxide more efficiently, two-stage leaching process was used to leach nickel and cobalt from Ruimu crude nickel cobalt hydroxide (MHP). The effects of pH value, temperature and time of first-stage leaching, and sulfuric acid dosage and time in second-stage leaching on the leaching effect of nickel, cobalt and manganese were investigated. The results show that under the conditions of the first stage leaching temperature of 70 ℃, pH value of 2.0~2.5, leaching time of 1.5 h, and sulfuric acid addition of second stage is 50%~70% of the first stage, the nickel and cobalt leaching effect is the best, which can reach 100% and 98.99% respectively, manganese leaching rate can be inhibited at 36.82%, and the slag rate is 5.32%. The cobalt and manganese content in slag is 0.71% and 55.55%, respectively. The total acid consumption is about 760 kg/t. According to the conditions of the small-scale experiment, the continuous expansion test results of 300 kg/d can achieve the leaching effect of the small-scale test.