Recovery of Lead and Zinc from Complex Industrial Waste of Zinc Process with Ammonium Acetate

Abstract

Zinc filter cakes (ZFCs) have economic values as secondary sources, but also are classified as hazardous waste and have negative effects on human health and the environment because they contain several heavy metals. Especially the extraction and recovery of lead and zinc metals from ZFCs will provide economic and environmental benefits. Therefore, in this study, extraction of lead and zinc with a weak acid (ammonium acetate, AmAc) leaching was investigated, and then cementation of dissolved Pb from the pregnant leach solution using zinc metal powder was studied. The effects of parameters such as AmAc concentration, leaching temperature, leaching time, and solid/liquid ratio on lead and zinc extraction were revealed with single factor. Lead recovery from leach solution was also examined in different time and temperature ranges. As a result of experimental studies, 81% of lead and 34% of zinc were extracted from ZFC under selected leaching condition; 3 M AmAc concentration, 70°C temperature, 1 h time, and 1/10 g/mL solid/liquid ratio. Cementation processes with zinc powder under 45°C and 120 min showed that 70% of lead ions were recovered from leach solution. Also, the activation energy for lead extraction with zinc powder was calculated as 33.4 kj/mole.