Experimental Study On Vacuum Distillation Of Crispy Sulfur And Lead Antimony Concentrate

Jamesonite is a kind of significant sulphide ores, the existing smelting process of jamesonite concentrate is thermometallurgy of sintering-shaft furnance smelting-converting, these difficulties in separating of Pb and Sb, the long process flow and the low level recovery of metal are the main disadvantages of existing process. Vacuum Metallurgy is a pollution-free, clean and efficient metallurgical method. This paper was trying to use the technology of vacuum metallurgy to achieve the target of separating Pb and Sb, by means of special structure of concentrate, and aiming at exploring a new process.It was characterized the elements and structure of jamesonite concentrate for first. It turned out that the concentrate contained jamesonite, pyrite and sphalerite. The analysis of TG-DSC shown that, the endothermic peak of DSC curve at 856.3K、 1260.8K andl420.3K indicated the decompositions of FePb4Sb6S14 and FeS2, the fusion of FeS.It was discussed the stability of PbS, Sb2S3, ZnS and FeS in the temperature range of 673K to 1073K by classical thermodynamics algorithm, results indicated that, PbS(s) was stable when the pressure was higher than 1Pa and temperature was lower than 1197K, and Sb2S3(1) was 1Pa,1066K, and ZnS(s) was 10Pa,1202K, and FeS could be stable all the time. The experiment of decomposition in vacuum furnace indicated that the low pressure would promote the decomposition of jamesonite concentrate, when the pressure reduced to 5～20Pa, the decomposition temperature dropped from 856.3K below 773K. The XRD spectrum of residue of 773K experiment indicated that FePb4Sb6S14 was decomposed into PbS, Sb2S3 and FeS.The theoretical calculation indicated that the order of volatility was Sb2S3, PbS and FeS. The distillation of stibnite demonstrated that the Sb2S3(Sb content 66.98wt%) can be successfully extracted from stibnite which Sb content was 27.82wt% at the temperature of 773K, keeping time of 30min and pressure of 5～15Pa. The distillation of jamesonite during 673K-1073K shown that the lowest Sb content in concentrate was 0.0088wt% when the temperature was 1073K and the keeping time was 90min, and the highest Sb content in condensation was 61.52wt% when the temperature was 873K and the keeping time was 20min. The distillation of jamesonite during 1173K～1673K shown that the optimum efficiency of separation Pb-Sb was when the temperature was 1473K. and the keeping time was 60min, the Pb and Sb content in the PbS condensation were 69.47wt% and 2.47wt%, and in Sb2S3 condensation were 3.11wt% and 70.54wt%. It demonstrated separating Pb-Sb by vacuum distillation was feasible.