Nickel recovery from reject laterite.

摘要

Falconbridge Dominicana C. Por A. operating in the Dominican Republic produces nickel as an iron-nickel alloy from laterite ore. Material that is rejected from their mining operations due to its incompatible chemistry is currently being stockpiled against mine depletion. Recent interest in recuperating nickel from this reject material led to the examination of the suitability of carbothermic reduction followed by magnetic separation for nickel recovery from this reject ore. Five parameters were considered in a Design of Experiment framework, namely: heating time; temperature; material type, coke addition and oxygen partial pressure. Magnetic separation was conducted with a Davis Tube and a low intensity hand magnet.; It was found that this reject material can successfully be treated using a carbothermic reduction process to produce 50 to 75 mum diameter metallic components within a gangue matrix. The recovery of nickel ranged from 61.7% to 21.9% to 16.4% in the high, low and non magnetic fractions, respectively, separated from the reduced material. The grade of nickel ranged from 1.97 wt% Ni to 1.58% to 0.75 wt% Ni in the high, low and non magnetic fractions, respectively.; Heating temperature had the greatest positive influence on the performance of the process followed by material type and heating time. Oxygen activity and coke addition were seen not to influence the performance. The Boudouard reaction was considered to be the rate controlling step and a maximum possible operating temperature was considered to depend on the physical properties of the material, specifically the softening temperature.