含铟酸性溶液二段中和法富集铟的生产实践

Production practice of indium enrichment by two-stage neutralization of indium-containing acid solution

某湿法炼锌厂以含铟酸性溶液为原料,采用石灰二段中和工艺富集回收溶液中的铟,该工艺在生产实践中存在预中和渣含铟损失高、预中和底流矿浆难过滤及中和沉铟底流矿浆难过滤等问题。通过把预中和石灰石浆由直管加入改为盘管加入,按35→25→15→10 g/L梯度控制预中和酸度,合理配料降低预中和前液的铁离子浓度,可降低预中和石膏渣含铟~100 g/t,并能改善预中和矿浆的过滤性能;通过把中和沉铟pH值由4.6提高至5.0并稳定控制,增加一个中和沉铟槽延长中和沉铟反应时间,可改善中和沉铟矿浆的过滤性能。

A zinc hydrometallurgy plant used lime two-stage neutralization process to enrich and recover indium from indium-containing acid solution,In production practice,this process has disadvantages of high loss of indium in pre neutralization slag,difficult filtration of pre neutralization underflow pulp,and difficult filtration of neutralization precipitation underflow pulp.By changing pre neutralization limestone slurry from straight pipe to coil pipe,controlling pre neutralization acidity according to gradient of 35→25→15→10 g/L,and reducing concentration of iron ion in pre neutralization solution by rational proportioning,the indium in pre neutralized gypsum slag could be reduced to~100 g/t and filtration performance of pre neutralized pulp was improved.Filtration performance of neutralization indium slurry was improved by raising pH value of neutralization indium from 4.6 to 5.0 and stably controlled,and adding a neutralization indium tank to prolong reaction time.