Research On A New Process For Removing Copper From Crude Tin

Coarse tin refining and produce lots of sulfur residue after sulfur in addition to copper,sulphur residue is a backlog of large amounts of valuable metals in sulfur residue efficient processing has been a technical problem of the tin smelting,carry out effective economic crude tin copper removal method,the maximum to avoid the difficulty of producing sulfur and recycling,is currently the tin smelting technology problem to be solved in this paper puts forward a kind of the SnS alternative S except Cu used to refining crude tin method,and has carried on the related research,the following main conclusions:（1）505 ～ 1154 k under the condition of SnS is difficult to decompose,volatile;Cu₂S will not volatilize or decompose at 1357～1403K.Under the same pressure condition,the volatilization relationship of Cu Sn Cu₂S SnS with the increase of temperature is as follows :SnS > Cu₂S> Sn> Cu.Under the pressure of 1×10⁵Pa,SnS can react with Cu at 690 K.1×10⁵Pa pressure under the condition of Cu₂S and Snto reaction,but reduce the system pressure,after reaction with SnCu₂S easier,also decreases the temperature of the reaction,when the pressure of 50 pa Cu₂S and Snreaction temperature is 1123 k thermodynamic analysis results show that,by changing the temperature and pressure conditions,can realize SnS and Cu in the reaction of Cu₂S and Sn,namely the SnS alternative S except Cu used,realize coarse tin refining in addition to copper,on the thermodynamics is feasible;（2）in the reaction between SnS and Cu,the conversion rate of Cu increased with the increase of reaction temperature.When the temperature was 1173 K,the conversion rate of Cu was 75.31% for 15 min.Under the same temperature,the conversion rate of Cu increased with the extension of reaction time,and the conversion rate of Cu reached 83.83% when the reaction time was 30 min.When Snexist in the reaction,SnS and displacement reaction of Cu was suppressed,Snand Cu quality ratio of 9:1,temperature of 1173 k,the reaction time for 30 min,Cu conversion rate of 55.82%,then add excess SnS can significantly improve the conversion rate of Cu,SnS and Cu when mass ratio for two times,the conversion rate can increase to 94% Cu combining the reality of crude tin refining copper removal,when Cu transfer rate is greater than 80%,the content of Cu is less than 0.1% in crude tin,pure tin products can be got through the follow-up production The results of the reaction between Cu₂S and Snshow that the reaction between Cu₂S and Sncan occur when the system pressure is reduced,and the effect of pressure on the reaction between Cu₂S and Snis greater than that of the reaction time.When the pressure is 50 Pa,the reaction temperature is 1123 K,and the holding time is 20 min,the copper conversion rate is 85%.（3）EPMA 、EDS analysis results of crude tin show that: in typical crude tin,impurity elements Fe and As will form the intermetallic compound AsFe,which occurs in the form of AsFe in crude tin;The impurity element Pb was separately enriched in the tin.The experimental results showed that the raw tin containing 91.55%Snand 0.33%Cu,the SnS content was 2 times the mass of Cu,the temperature was 1173 K,the reaction time was 30 min to remove Cu,and the copper slag produced by adding SnS to remove copper was 50 Pa,the temperature was 1173 K,and the heating time was 20 min.The direct yield of Snin the whole process was 93%,and that of Cu in tin containing copper was 97%.In tin removing copper,the direct yield of copper is 97%.Compared with the traditional method,SnS is used as the crude tin removing Cu agent.The new process of crude tin removing Cu combined with vacuum distillation has the advantages of simple flow,high efficiency and high copper removal rate of recycling with small SnS pollution.