氯化物体系中微量金的协同萃取分离研究

Synergistic Extraction and Separation of Trace Gold in Chloride System

研究了用DIBK(二异丁基酮,HA)和TBP(磷酸三丁酯,B)协同萃取体系分离和富集氯化物体系中的金,考察了萃取体系及组成、萃取时间和温度、水相中氯离子浓度、萃取相比(V_(O)/V_(A))对金萃取分离性能的影响,并采用斜率法初步探究萃取机制。结果表明:在协同萃取体系为TBP-DIBK、萃取剂总浓度1.5 mol/L、n(TBP)∶n(DIBK)=1∶4、萃取时间20 min、萃取温度20℃、V_(O)/V_(A)=2/1、水相中氯离子浓度6 mol/L条件下,金萃取率可达98.82%,最大金/铜萃取分离系数为1189.05;斜率法研究表明,萃合物组成可能为[AuCl_(6)·3A·B],其萃取化学反应式可改写为Au^(3+)+6Cl^(-)+3HA+B→[AuCl_(6)·3A·B]+3H^(+)。

The separation and enrichment of precious metal gold in chloride system with synergistic extraction system composed of DIBK(HA)and TBP(B)was stuied.The effects of extraction system and composition,extraction time,extraction temperature,aqueous chloride ion concentration,and extraction ratio(V_(O)/V_(A))on the separation performance of gold extraction was investigated,and the extraction mechanism was preliminarily explored by slope method.The results indicate that under the conditions of synergistic extraction system of TBP-DIBK,total extractant concentration of 1.5 mol/L,n(TBP)∶n(DIBK)=1∶4,extraction time of 20 min,extraction temperature of 20℃,V_(O)/V_(A)=2/1,aqueous chloride ion concentration of 6 mol/L,the extraction rate of gold can reach 98.82%.The maximum gold/copper extraction separation coefficient is 1189.05.Gradient method suggests that the composition of the extract may be[AuCl_(6)·3A·B].The extraction chemical reaction formula can be rewritten as:Au^(3+)+6Cl^(-)+3HA+B→[AuCl_(6)·3A·B]+3H^(+).