1 School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, China; 2 Beibu Gulf New Materials Co., Ltd., Beihai 536000, Guangxi, China
Upgrade of nickel and iron from low-grade nickel laterite by improving direct reduction-magnetic separation process
1 School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, China; 2 Beibu Gulf New Materials Co., Ltd., Beihai 536000, Guangxi, China
摘要 Low-grade saprolite nickel laterite, characterized by complicated minerals composition and fine-grained and complex dissemination, was commonly treated with a low recovery efficiency of Ni and Fe by conventional methods. Hence, an improved direct reduction and magnetic separation process was proposed. Meanwhile, the mechanisms on the enhanced growth of the Ni–Fe particles and the phase transformation in the nickel laterite pellets were explored. The low-nickel concentrates as a nucleating agent can obviously decrease the activation energy for growth of Ni–Fe alloy particles during the improved direct reduction process from 197.10 to 154.81 kJ/mol when the low-nickel concentrates were added from 0 to 20%. Hence, it is able to decrease nucleation barrier, induce the growth of Fe–Ni alloy particles and increase their average size. As a result, the size of Ni–Fe particles in the pellets from less than 10 lm grew to more than 20 lm, which is beneficial for the full liberation and recovery of Ni and Fe in subsequent magnetic separation process. Therefore, the preferable Ni–Fe alloy concentrates with 6.44% Ni and 82.48% Fe can be prepared with corresponding recovery rates of 96.90% and 95.92%, respectively, when adding 20% low-nickel concentrates.
Abstract：Low-grade saprolite nickel laterite, characterized by complicated minerals composition and fine-grained and complex dissemination, was commonly treated with a low recovery efficiency of Ni and Fe by conventional methods. Hence, an improved direct reduction and magnetic separation process was proposed. Meanwhile, the mechanisms on the enhanced growth of the Ni–Fe particles and the phase transformation in the nickel laterite pellets were explored. The low-nickel concentrates as a nucleating agent can obviously decrease the activation energy for growth of Ni–Fe alloy particles during the improved direct reduction process from 197.10 to 154.81 kJ/mol when the low-nickel concentrates were added from 0 to 20%. Hence, it is able to decrease nucleation barrier, induce the growth of Fe–Ni alloy particles and increase their average size. As a result, the size of Ni–Fe particles in the pellets from less than 10 lm grew to more than 20 lm, which is beneficial for the full liberation and recovery of Ni and Fe in subsequent magnetic separation process. Therefore, the preferable Ni–Fe alloy concentrates with 6.44% Ni and 82.48% Fe can be prepared with corresponding recovery rates of 96.90% and 95.92%, respectively, when adding 20% low-nickel concentrates.
Hong-yu Tian,Zheng-qi Guo,Ruo-ning Zhan, et al. Upgrade of nickel and iron from low-grade nickel laterite by improving direct reduction-magnetic separation process[J]. Journal of Iron and Steel Research International, 2022, 29(08): 1164-1175.
2022, Vol. 29 
