The Study Of Recovery Of Copper And Cobalt From Cobalt-enriched Copper Converter Slag

The high value-added Co or Ni from copper-concertrated ore is enriched in converter slag from the process of converter blowing insmelting process.But Co or Ni can not be effectively recycled through electric furnace or mineral separating method.So it’s urgent to develop technologies of extrating valueable metals from converter slag.The converter slag is supplied by Chambishi Copper in Zambia.In order to enrich,separate and extract these valuable metals,the theory was studied in detail in this paper.The XRD analysis of the converter slag have been conducted.Result showed that the main phase were fayalite and magnetite,with lesser amount of glass.Copper is entrapped in the slag mostly as chalcocite and metallic copper.But most copper exists as metallic copper.Cobalt is concentrated in fayalite and magnetite as solid solution by replacing Fe2+in their lattices.The leaching test for the cobalt-rich copper converter slag were studied by sulfuric acid.Test result showed that:leaching at sulfuric acid initial concentration of2mol/L, leaching temperature of85℃, leaching time of2.5h, liquid-to-solid ratio of6:1(ml/g).The average leaching efficiency of Co and Cu reach95.4%and42.3%.To decrease the pH of the solution to2by two cycle leaching.then we tested the extraction of copper with16%Lix973N-kerosene system under the phase of ratio (O/A)=1:1from the second stage leaching solution,which containing22g/L Cu2+,the solution pH≈2and high concentration of Fe3+.The result showed that the copper concentration in raffinate could be decreased to about0.17g/L through four stage cross-flow extraction.It meant a high efficient extraction recovery of copper could be reached from high concentration of copper and iron.The copper loaded organic phase was stripped with180g/l of sulfuric acid solution with36.7g/L Cu2+,Result showed that when the phase ratio decreased from5:1to8:1,the stripping ratio of Cu2+ increased from25.48%to88.75%,which meant a high efficient stripping recovery of copper could be achieved.During the processes of iron removing by sodium jarosite,.reaction temperature,reaction time,endpH have been researched.The result showed that:under the best conditions of reaction temperature90℃,reaction time4h,endpH≈2-2.5.The ratio of iron removing could reach over96%and the loss of Co2+was3.2～3.5%,achieving the purpose of removing iron and reserving cobalt.After extracting copper and removing iron from leaching solution,16%Lix973N-kerosene system was selected to remove the residual copper and5%P204-kerosene system was selected as the extraetant for the advanced removal of iron.Then we get cobalt sulfate solution.Cobalt oxalate was obtained by oxalate precipitating at last.