铟直萃工艺降低萃余液TOC含量的研究

Research on Reducing the TOC Content of Extraction Residue in Indium Direct Extraction Process

在湿法锌冶炼时锌精矿通过焙烧浸出产生的氧化锌酸上清中含有有价金属铟,目前国内回收铟普遍采取直接萃取的工艺,由于萃取剂P204为有机物,萃余液会夹带TOC,生产中采用活性碳吸附除TOC,借助活性碳能够富集萃余液中TOC的原理,让活性碳与萃余液充分接触,降低萃余液中的TOC含量。由于不同厂家的活性炭质量存在差异且当溶液中TOC含量低于200 mg/L时活性碳的除TOC率大幅降低。文章通过对影响萃余液TOC的原因进行分析,探索出酸洗、碱洗、温度、比重等各类因素对萃余液TOC的影响,确定了降低萃余液TOC的工艺改进措施,稳定控制萃余液TOC≤35 mg/L。

During wet zinc smelting,the zinc concentrate contains valuable metal indium in the zinc oxide acid supernatant produced by roasting and leaching.Currently,direct extraction is commonly used to recover indium in China.Due to the organic nature of the extmactant P204,the rffrate will cary T0C,and activated carbon is used to.adsorb and remove T0C in production.By utilizing the principle that activated carbon can enrich T0C in the raffinate,the activated carbon can come into contact with the heavy roots of the raffinate,reducing the TOC content in the rafinate.Due to differences in the quality of activated carbon from different manufacturers,and when the T0C content in the solution is below 200 mg/L,the TOC removal rate of activated carbon si gnificantly decreases.This article analyzes the reasons that affect the TOC of the raffinate,explores the effects of various factors such as acid w ashing,alkali washing,temperature,and specific gravity on the T0C of the rffinate,and determines process improvement measures to reduce the T0C of the rffnate,stably controlling the T0C of the rffnate to≤35 mg/L.