Effect of Co-Reduction Conditions of Nickel Laterite Ore and Red Mud on Ferronickel Particle Size Characteristics and Grindability of Carbothermic Reduction Products

Abstract

The carbothermic co-reduction of nickel laterite ore and red mud realized the simultaneous reduction of nickel, iron in laterite ore, and iron in red mud at high efficiency. Nickel and iron in nickel laterite ore and iron in red mud were recovered in the form of ferronickel. The size characteristics of ferronickel particles and grindability of carbothermic reduction products are essential for obtaining good technical indicators. The influence of co-reduction conditions on ferronickel particle size and relative grindability was investigated by a carbothermic reduction test, particle size analysis, and relative grindability determination. The mean size of ferronickel particles increased and the proportion of coarse particles grew with improving carbothermic reduction temperature, increasing appropriately anthracite dosage, and prolonging carbothermic reduction time. However, the relative grindability of carbothermic reduction products deteriorated when reduction temperature was improved and the reduction time was extended. The relative grindability was negatively correlated to the ferronickel particle size. The carbothermic reduction temperature had the most dominant effect on the ferronickel particle size and relative grindability, followed by the anthracite dosage and reduction time. More nickel-bearing and iron-bearing minerals were reduced to metallic state with raising reduction temperature and increasing appropriate anthracite dosage. The fine ferronickel particles agglomerated and merged into bulk ferronickel grains with a prolonged reduction time. The results will provide theoretical guidance for the recovery of nickel and iron by co-reduction of nickel laterite ore and red mud.