氨法浸出氧化锌烟尘制取活性氧化锌

Preparation of activated zinc oxide from zinc oxide dust by ammonia leaching process

为实现冶锌废渣中锌资源的再利用,以商洛炼锌厂冶锌过程中产生的氧化锌烟尘为原料,采用氨法浸出-微波蒸氨-火法焙解工艺制得粒度分布均匀的球状活性氧化锌.对锌的浸出工艺及氧化锌前驱体的热解工艺进行研究,并利用TG/DTA、XRD、SEM等测试手段对产品进行结构及物相表征.研究表明,氨法浸出过程中总氨浓度为8 mol/L、pH为10.0、液固比为4∶1、浸出温度为40℃时,锌的浸出率最高可达92.05%.浸出液经两段净化除杂后,80℃下蒸氨25 min时,制得前驱体碱式碳酸锌.在400℃焙解120 min制得平均粒径约为3μm,六方晶系的球状活性氧化锌.此法对设备要求不高,生产成本低,工艺流程短,具有较强的实用性.

For the purpose of reuse of zinc resources from zinc residues, spherical activated zinc oxide withuniform size distribution was synthesized from zinc oxide dust via ammonia leaching, ammonia distillation withmicrowave, and calcination, which was brought from zinc smelting process by Shangluo Smelter. Then, theprocess of zinc leaching and pyrolysis of precursor was studied, and the product was characterized by TG/DTA, XRD and SEM. The results indicated that with the total ammonia concentration of 8 mol/L, the pHvalue of 10.0, the liquid-solid ratio of 4∶1, the leaching temperature of 40 ℃, the leaching efficiency couldreach the maximum value of 92. 05%. Basic zinc carbonate, the precursor of activated zinc oxide, wasprecipitated from the leaching solution by two-stage purification and ammonia distillation by microwave for25 min at the constant temperature of 80 ℃. Then, spherical activated zinc oxide, a kind of hexagonal sheetcrystal with average diameter of 3 μm, was formed under calcination temperature of 400 ℃ for 120 min.Because of the advantages of short flow, 1ow cost and low equipment requirement, the method was of greatvaluable, which provided a new approach for the reuse of secondary zinc resources.