Recovery Of Valuable Metals From Low-grade Heterogenite

Cobalt is an important strategic resource. With the continuing exploitation of cobalt resource, high-grade cobalt ores become less and less. Therefore, recovery of metal values from low-grade cobalt ores has received extensive attentions. A technological process of recovering copper and cobalt from low-grade heterogenite by acid leaching and ammonia leaching process was investigated in this paper.In acid leaching process, the influences of the type of reducing agent, leaching temperature, acid concentration, etc on leaching rate of cobalt and copper were investigated through single-factor experiments. The optimal conditions at which the leaching efficiency of copper and cobalt were 99.06% and 98.87% were as follows: T = 60℃, c ( H 2SO4) = 3 mol/L, L/S ratio = 2:1, time = 60 min, and the dosage Na 2SO3 is 10% wt of the heterogenite. And a flowsheet of Fe removal by jarositeâ†'Al removal by Na 2CO3â†'Ca , Mg removal by NaFâ†'Cu recovery by N902â†'Co recovery by evaporative crystallization is used. Extraction rate of Cu reaches 98.00% , stripping rate > 99.90%, loss rate of Co is less than 4.00%, recovery rate of Cu and Co is about 91% and 88% respectively, which achieves recovery of copper and cobalt in acid leaching liquid.In ammonia leaching process, the influences of the amount of reducing agent, leaching temperature, liquid-solid ratio, etc on leaching rate of cobalt and copper were investigated. The optimal conditions at which the leaching efficiency of copper and cobalt were 96.07% and 98.24% were as follows: time = 5 h, T = 50℃, the amount of ammonia is 1.2 times of theoretical, C(NH3):C [(NH4)2SO4] =1:3, L/S ratio = 3:1, and the dosage of Na 2SO3 is 0.5 times of the heterogenite's mass. And a flowsheet of Cu recovery by Lix54â†'Co recovery by evaporative crystallization is used. Counter current extraction and cross current extraction are compared with their relative metits. The result shows the former superior to the latter, the extraction rate of Cu > 98.00%, stripping rate reaches 100%, and Co free of losses, recovery rate of Cu and Co is about 94% and 98% respectively, which achieves recovery of copper and cobalt in ammonia leaching liquid.Acid leaching process has the advantages of short leaching time, high leaching rate and more mature follow-up process. And selective leaching of valuable metals was achieved in ammonia leaching process. Both of them can be applied in the extraction of metal values from heterogenite and similar materials effectively in industry.