Theoretical Research On Short-process Copper Smelting From Chalcopyrite Mixed Chalcopyrite And Experimental Verification Of Optimal Slag Type

The smelting-blowing two-stage technology was still the main method in the current pyrometallurgical copper smelting process.With the problems of flue gas fluctuate and the SO₂ leak because of intermittent operation of conventional copper smelting process,resulting in serious low-level pollution.As the requirements of environmental protection and energy saving and emission reduction became more and more strict,the direct-to-blister smelting technology had been received attention gradually,which would become the focus of future research in the pyrometallurgical copper industry.The process also had the characteristics of strengthening the smelting process,improving productivity and simplifying the smelting process.The subject based on high-grade copper sulfide concentrates of chalcocite to study the operability of the direct-to-blister smelting process through thermodynamic analysis and experimental results with addition of chalcopyrite concentrates.The theoretical thermodynamic data of chalcocite and chalcopyrite concentrates smelting directly were respectively calculated by Fact Sage thermodynamics software,which were used as raw materials in the article.Based on the premise of slag type and heat complementary,adjusting the chalcocite and chalcopyrite addition ratio to the smelting iron-silicon ratio of 0.4,0.6,0.9 and 1.2,using additive Ca O to reduce the viscosity of the slag,discussed the relationship between phase balance,slag composition,element content in blister copper and copper direct yield with temperature at1100?1350?,and analyzed the smelting parameters such as slag type,copper direct yield,blister copper grade,S content in blister copper,copper content in slag,slag viscosity and slag make at 1300?.With the analysis of thermodynamic results,the optimal slag-type feasibility control experimental program was verified experimentally,and the effects of gas injection rate,blowing time and settling time on the direct copper yield were investigated.The experimental results obtained under the best optimal conditions were analyzed by means of chemical element analysis,XRD,EPMA and compared with the theoretical data.The normal smelting could not be carried out due to the precipitation of Si O₂ in direct smelting of chalcocite,which led the viscosity of the slag increase and the fluidity was poor.And direct smelting of chalcopyrite was also difficult because of difficult slag formation and insufficient self-heating ability,and the high content of spinel in slag.By adjusting the chalcocite and chalcopyrite addition ratio,using additive Ca O to reduce the viscosity of the slag,could get the copper direct yield was 83.31%?95.53%and the copper content in slag was 4.26%?16.45%,and the direct-to-blister smelting of chalcocite mixed with chalcopyrite could be realized theoretically.The experimental verification of chalcocite mixed with chalcopyrite showed that under the optimal conditions of 0.4 min/L injection rate,1.4 times blowing time of theoretical time and 2 h settling time,the copper direct yield was 71.83%?83.79%and the copper content in slag was 15.84%?18.02%.Because the mechanical entrainment made the copper content in the slag higher,resulting in a lower copper yield than the theoretical value.We could form a theoretical guide for the direct-to-blister production process of chalcocite mixed with chalcopyrite from the research of the subject.