Intensifying the selective sulfidation of nickel in saprolitic laterites by sodium salts

Nickel sulfide concentrate was an important raw material for battery-grade nickel sulfate. To efficiently separate nickel from saprolitic laterite to product nickel sulfide concentrate, a novel and clean sulfidation-flotation process aimed to enhance selective sulfidation and particle growth through sodium carbonate was proposed herein. The effects of temperature, time, sulfur dosage, Na salts, and carbon additions on the selective sulfidation of nickel are systematically studied. Experimental results show that sodium carbonate can destroy the silicate structure, release nickel in the silicate, and form a low-melting point phase, promoting the aggregation of nickel sulfide, thereby achieving the purpose of promoting the sulfidation of nickel and the growth of synthetic nickel matte particles. Under the optimal conditions, 85.7% Ni and 27.1% Fe could be sulfated.