白烟尘两段逆流浸出工艺研究

Study on Two-stage Countercurrent Leaching Process of White Dust

针对白烟尘既富含铜、铅、锌、铋等多种有价金属,又含有砷、镉等有害元素的特点,提出一种两段逆流浸出工艺。采用该工艺进行实验处理某铜冶炼厂生产的白烟尘,分别考察了酸浸方式、初始硫酸质量浓度、酸浸液固比、酸浸温度、酸浸时间对铜砷浸出的影响。探索出最佳工艺条件液固比为4∶1,初始硫酸质量浓度80g/L,反应温度为80℃,反应时间为2 h。二次浸出液返回继续浸出白烟尘,此时白烟尘铜、锌、砷浸出率分别为95.7%、98.5%、92.2%,而浸出渣中铜、锌、砷品位降至0.42%、0.50%、1.28%。铅、铋的品位实现有效富集,二次酸浸渣中品位分别为47.73%和9.72%,相比原料分别富集约2.6倍和4.5倍。

According to the characteristics of white dust,which is rich in many valuable metals such as copper,lead,zinc,bismuth and other harmful elements such as arsenic and cadmium,the paper puts forward a two-stage countercurrent leaching process.The process was used to treat white dust from a copper smelter,which investigate the effects of acid leaching method,initial sulfuric acid mass concentration,acid leaching liquid-solid ratio,acid leaching temperature and acid leaching time on copper and arsenic leaching.The optimal process conditions were obtained:the liquid-solid ratio of 4∶1,the initial sulfuric acid mass concentration of80 g/L,the reaction temperature of 80℃,and the reaction time of 2 h.The secondary leaching solution recycles for continuous leaching of white dust.At this time,the leaching rates of copper,zinc and arsenic in the white dust are 95.7%,98.5%and 92.2%respectively,while the grades of copper,zinc and arsenic in the leaching residue are reduced to 0.42%,0.50%and 1.28%.The grades of lead and bismuth are effectively enriched.The grades of lead and bismuth in the secondary acid leaching residue are 47.73%and9.72%respectively,which are about 2.6 times and 4.5 times richer than the raw materials.