浸锌渣夹带水溶锌的湿法提取工艺试验

Experiments on Hydrometallurgical Process for Extraction of Water-Soluble Zinc from Leaching Residues

针对湿法炼锌产出的铅银渣和铁矾渣夹带水溶锌含量高的问题,采用洗涤—净化—萃取工艺回收锌,考察反应温度、酸度、时间等因素的影响,得到优化工艺条件。在室温、液固比5∶1、洗水酸度5g/L、洗涤时间30min的条件下进行洗涤,铅银渣和铁矾渣中锌的回收率可分别达到61.4%和79.6%。以熟石灰为中和剂对溶液进行中和净化,控制终点pH4.0,溶液中的铁可完全沉淀去除,锌几乎没有损失(<0.9%)。在有机相组成30%P204+70%磺化煤油、萃取相比O/A=2/3、萃取混合时间3min条件下萃取锌,经三级逆流萃取,锌萃取达到96%以上,再用锌电积贫液反萃,得到富锌溶液。该工艺操作简单,实现了浸锌渣中夹带水溶锌的资源化利用,还可与原有湿法炼锌工艺有机衔接。

Address to high content of water-soluble zinc in Pb-Ag residue and jarosite residue produced by zinc hydrometallurgy,washing-purification-solvent extraction process was adopted to recover zinc.Effects of reaction temperature,acidity and time on zinc recovery were investigated to obtain the optimum process conditions.Zinc recovery in Pb-Ag residue and jarosite residue is 61.4%and 79.6%respectively when washing is carried out at room temperature with L/S=5,washing water acidity of 5 g/L and washing time of 30 min.Solution after washing is neutralized and purified with hydrated lime as neutralizer by controlling final pH value at 4.0.Iron in solution can be completely precipitated and removed,while zinc loss is 0.9%below.Zinc extraction rate of three-stage countercurrent extraction is 96%above under the conditions including organic phase composition of 30%P204+70%sulfonated kerosene,extraction ratio O/A=2/3,and extraction time of 3 min.Zinc-rich solution is obtained by stripping with zinc electrowinning lean solution.This hydrometallurgical process is simple in operation and realizes resource utilization of water-soluble zinc entrained in zinc leaching residues.It can be integrated with the original zinc process.