Direct Extraction of Nickel and Copper from Low-Grade Nickel Sulfide Ore by Chlorination Roasting with Mixed MgCl2 center dot 6H(2)O and NaCl

A new extraction technology of chlorination roasting with a mixture of MgCl2 center dot 6H(2)O and NaCl was investigated to co-extract nickel and copper from low-grade nickel ores. The effects of some key factors on the extraction of nickel, copper, and iron were studied, and the results show that,when the roasting temperature is 850 degrees C, the roasting time is 1.5 h, the mass ratio of magnesium chloride hexahydrate to sodium chloride is 5:2, the mass ratio of ore to chlorination agent is 1:0.6, and the ore particle size is 180-200 mesh, the extraction of nickel and copper can reach 83.6% and 81.3%, respectively, but less than 3% of impurity iron enters the leach solution. XRD and SEM were used to analyze the mineral phase of the roasted products and leach residue to determine the phase transformation. The kinetics of the chlorination process were investigated by the Kissinger and Flynn-Wall-Ozawa method to determine the average activation energy and the kinetic equation.