Experimental Study On Separation Of Lead Sulfide And Antimony Sulfide From Brittle Sulfide-lead Antimony Ore By Vacuum Distillation

After the lead-antimony alloy was obtained by the smelting of jamesonite,due to the physical and chemical properties of lead and antimony are similar,it is difficult to completely separate them,and the current treating process of jamesonite is complicated,the cost is high,and the pollution is serious.The National Engineering Laboratory for Vacuum Metallurgy,Kunming University of Science and Technology have applied vacuum thermal decomposition-fractional condensation process in treating jamesonite.For the purpose of obtaining lead sulfide and antimony trisulfide products,This process directly separates lead and antimony in the form of PbS and Sb₂S₃,which provides a reference for efficient utilization of jamesonite.However,it has problems such as the reaction temperature is too high,the purity of PbS and Sb₂S₃are not enough.To this end,this paper proposes a vacuum thermal decomposition-two step distillation method to separate lead sulfide and antimony trisulfide from jamesonite concentrate.The following work was carried out:?1?TG-DSC thermal analysis shows that the thermal decomposition temperature of FePb₄Sb₆S₁₄ is 859K.Atmospheric thermal decomposition experiments show that FePb₄Sb₆S₁₄ can't be completely decomposed even temperature reach 1273K,and Pb₂Sb₂S₅ is the main intermediate phase.The thermal vacuum decomposition experiments indicate that FePb₄Sb₆S₁₄ starts decompose at 823K and completely decompose at 973K.?2?The thermal stability of Sb₂S₃,FeS and ZnS was theoretically calculated.The thermal stability of PbS was theoretically calculated and experimentally studied.The results show that at 10Pa,823¹123K,Sb₂S₃ will only evaporate,ZnS won't have any reaction below 1273K,at the temperature lower than 1809K,FeS won't have any reaction;PbS starts sublimation at 996K,gaseous lead sulfide could decompose.Experimental result indicates gaseous lead sulfide decompose at 1023K,but by expanding its volatilization area,accelerating its condensation,lead sulfide won't decompose,only sublimate.?3?The vacuum distillation experiments show that:at 10Pa,973K,with holding time of 60 min,the direct yield of antimony is 99%,the residual antimony content is less than 1%,and the purity of condensed antimony trisulfide is higher than 96%.The residue after one-step distillation was distilled again at 1123 K,with holding time of60 min.The direct yield of lead was 99.5%,the residual lead content was less than0.6%,and the purity of condensed lead sulfide was higher than 98%.The results show that through vacuum decomposition-two step distillation process,the experimental temperature was reduced by 350K compared with vacuum decomposition-fractional condensation process,and the purity of lead sulfide and antimony trisulfide is also increased from 94% to 96% to 96% and 98% respectively.