针对现行湿法炼锌综合回收铟过程中存在的铟分散损失严重和直收率低的问题,采用直接萃取法从次氧化锌酸性浸出液中回收铟,考察了萃取剂浓度、混合时间、硫酸浓度和萃取温度等因素对铟及主要金属离子萃取率及盐酸浓度和相比对铟反萃率的影响,绘制了萃取平衡等温线和反萃平衡等温线,进行了小型模拟实验和连续逆流萃取-反萃实验,重点考察主要金属离子在萃取和反萃过程中的分布与走向.结果表明,以10%P204为有机相,在相比(A/O)为2/1、逆流萃取级数为3级的条件下,浸出液中铟萃取率达99.9%,杂质铁、锌和镉的萃取率分别为1.5%,0.5%和1.1%.得到的负载有机相采用6 mol/L盐酸反萃,相比为1/5时4级反萃后,铟反萃率达100%,镉、锌和铁基本被全部反萃,反萃后的贫有机相可循环使用.
In order to improve the comprehensive recovery rate of indium from the zinc hydrometallurgy process,a direct solvent extraction process was employed to selectively extract indium from the leaching solution of zinc oxide.The extraction rates of indium and other ions with P204 were studied under different parameters such as concentration of extractant,contact time,acid concentration,and temperature.Besides,the effects of concentration of HCl and phase ratio on the stripping rate of indium were carried out.Extraction and stripping isotherm were prepared to determine the number of stages required for quantitative extraction and stripping of indium at the chosen aqueous to organic phase ratio(A/O ratio).A pilot test and continuous countercurrent extraction test were developed to study the behavior of various metal ions.Quantitative indium was extracted by 10% P204 with three stages countercurrent extraction at A/O ratio of 2/1.The extraction rate of indium reached 99.9%,while the extraction rates of iron,zinc and cadmium were 1.5%,0.5% and 1.1%,respectively.Indium in the P204 loaded organic was effectively stripped by 6 mol/L HCl with four stages at A/O ratio of 1/5 and the stripped organic phase can be reused in the extraction process.