Co-extraction of valuable metals and kinetics analysis in chlorination process of low-grade nickel-copper sulfide ore
(1. School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004, China;
2. School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China;
3. School of Metallurgy, Northeastern University, Shenyang 110819, China;
4. GE-HPEC-NTC Energy Services (Qinhuangdao) Co., Ltd., Qinhuangdao 066000, China)
2. School of Materials Science and Engineering, Northeastern University, Shenyang 110819, China;
3. School of Metallurgy, Northeastern University, Shenyang 110819, China;
4. GE-HPEC-NTC Energy Services (Qinhuangdao) Co., Ltd., Qinhuangdao 066000, China)
Abstract: To efficiently co-extract Ni and Cu from low-grade nickel-copper sulfide ore, chlorination roasting with NH4Cl followed by a water leaching process was investigated. The results show that 98.4% Ni and 98.5% Cu can be synchronously extracted when the ore particle size is 75-80 μm, the roasting time is 2 h, the mass ratio of NH4Cl to ore is 1.6:1 and the roasting temperature is 550 °C. The evolution behavior of various minerals was elucidated using X-ray diffraction (XRD) coupled with scanning electron microscopy (SEM). The kinetics of the chlorination process based on the differential thermal and thermogravimetric analysis (DTA-TG) data was analyzed by Kissinger method and Flynn-Wall-Ozawa (FWO) method. The chlorination process of low-grade nickel-copper sulfide ore mainly contains two stages: the decomposition of NH4Cl and the chlorination of ore. The maximum apparent activation energies (Ea) at two stages are determined to be 114.8 and 144.6 kJ/mol, respectively. The condensed product of exhaust gas is determined to be ammonium chloride, which can be recycled as the reactant again, making the process economic and clean.
Key words: low-grade nickel-copper sulfide ore; chlorination roasting; synchronous extraction; phase evolution; kinetics