The Aggregation and Growth of Ferronickel Particles During the Reduction of Laterite Nickel Ore

The main source of nickel has gradually become the recovery of ferronickel concentrate from low-grade laterite nickel ore. In this work, high-grade ferronickel concentrate was prepared by a reduction roasting-magnetic separation process, and low-grade ferronickel concentrate and CaF2 were used as composite additives to promote the aggregation and growth of ferronickel particles in the reduction roasting stage. The results showed that when the amount of low-grade ferronickel concentrate added was 30 wt.% and the amount of CaF2 added was 9 wt.%, high-grade ferronickel concentrate with nickel grade of 7.76 wt.% and iron grade of 67.27 wt.% could be obtained; the recovery rates for nickel and iron were 98.90% and 85.17%, respectively. Adding only ferronickel concentrate caused a small effect on the aggregation and growth of ferronickel particles. When ferronickel concentrate and CaF2 were added, the aggregation effect of ferronickel particles was obvious, and the maximum particle size and average particle size increased significantly. The XRD and FTIR analyses indicated that after CaF2 was added, the silicate structure in the raw ore changed from serpentine to forsterite and tremolite, which lowered the melting point and promoted the aggregation and growth of ferronickel particles.{GRAPHIACAL ABSTRACT}