環境

[2P0115-20-04] Effects of Al powder addition on Pb removal from zinc leach residues in acidified chloride solution

○Marthias Silwamba^1,3, Ryota Hashizume¹, Tomoki Fukushima¹, Carlito. B Tabelin², Ilhwan Park¹, Sanghee Jeon¹, Kawawa Banda³, Meki Chirwa³, Imasiku Nyambe³, Mayumi Ito¹, Naoki Hiroyoshi¹ (1. Hokkaido University, 2. The University of New South Wales, 3. The University of Zambia)

Keywords:Leaching, Cementation, Zinc leach residues, Lead

Zinc leach residues (ZLRs), the solid waste produced during zinc hydrometallurgical extraction processes, are widely known to be hazardous to the environment because they contain toxic heavy metals like lead (Pb). In this study, Pb removal from ZLRs that were produced and dumped more than 35 years ago in Kabwe, Zambia, was investigated. ZLRs was leached in NaCl-HCl solution of different compositions with and without Al powder addition. In case when ZLRs were leached with Al powder, Pb were extracted from ZLRs into leaching solution and it was sequestered from the leaching pulp via cementation with Al powder. Cemented Pb agglomerated and was separated from the leaching pulp by sieving. Compared to Pb removal without Al powder, the addition of Al powder drastically increased Pb removal from 2.8 to 36% for 0.05 M HCl and 3.5 to 68% for 0.1 M HCl solution containing 0.5 M NaCl.