Pretreatment study on chloridizing segregation and magnetic separation of low-grade nickel laterites

The chloridizing segregation and magnetic separation of low-grade nickel laterites from Yunnan province of China was investigated. The nickel laterites were characterized by microscopic investigations, using X-ray diffractometry (XRD) and energy dispersive spectrometry (EDS) techniques. The pellets, which were prepared with magnesium chloride and coke as chloride agent and reductant respectively, were heated to a high temperature, and the pellets after cooling were crushed for magnetic separation. A series of experiments were conducted to examine the effect of chlorinating agent dosage, reductant dosage, chloridizing temperature and chloridizing time on enrichment grade of Ni and Co. The results indicate that the four factors have significant effects on the extractions of Ni and Co. The optimum conditions are as follows: the amounts of magnesium chloride and coke are 6% and 2%, respectively, chloridizing temperature is 1 253 K, and chloridizing time is 90 min. Under the conditions, extractions of Ni and Co reach 91.5% and 82.3%, respectively.