Papers

Peer-reviewed
Aug, 2020

Detoxification of lead-bearing zinc plant leach residues from Kabwe, Zambia by coupled extraction-cementation method

Journal of Environmental Chemical Engineering
  • Marthias Silwamba
  • Mayumi Ito
  • Naoki Hiroyoshi
  • Carlito Baltazar Tabelin
  • Tomoki Fukushima
  • Ilhwan Park
  • Sanghee Jeon
  • Toshifumi Igarashi
  • Tsutomu Sato
  • Imasiku Nyambe
  • Meki Chirwa
  • Kawawa Banda
  • Hokuto Nakata
  • Shouta Nakayama
  • Mayumi Ishizuka
  • Display all

Volume
8
Number
4
First page
104197
Last page
104197
Language
English
Publishing type
Research paper (scientific journal)
DOI
10.1016/j.jece.2020.104197
Publisher
Elsevier BV

Zinc plant leach residues (ZPLRs) are hazardous solid wastes generated from zinc metal production owing to their substantial contents of lead (Pb), a toxic heavy metal. This study investigated the detoxification of historic ZPLRs from Kabwe, Zambia by removing Pb using a coupled extraction-cementation method in chloride media. For the coupled extraction-cementation method, micro-scale zero-valent iron (mZVI) was added during ZPLRs leaching in acidified chloride solution. Cemented Pb on the surface of mZVI was recovered easily from the leaching pulp by magnetic separation. Pb removal was evaluated in different solution compositions (NaCl:1-5.13 M, HCl: 0-0.1 M) with and without the addition of mZVI. The addition of mZVI during ZPLRs leaching (i.e., coupled extraction-cementation) increased Pb removal from 3% to 24%, 1.3% to 27.5%, 5.2% to 34.9%, and 6.5% to 55.8% when NaCl concentration was fixed at 0.86 M and HCl concentrations were 0 M, 0.01 M, 0.05 M and 0.1 M, respectively. When NaCl concentration was increased above 3.42 M and HCl maintained at 0.1 M HCl, Pb removal increased to 80%. Analysis of the Pb-loaded mZVI (magnetic fraction) by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and X-ray photoelectron spectroscopy (XPS) revealed that Pb was recovered during leaching via cementation as Pb degrees. The toxicity characteristic leaching procedure (TCLP) and in vitro solubility and bioavailability research consortium gastric phase (SBRC-G) tests for Pb of ZPLRs before and after treatment decreased drastically from 11.3 to 3.5 mg/L (below 5 mg/L threshold) and 12 300 to 2 840 mg/Kg, respectively.

Link information
DOI
https://doi.org/10.1016/j.jece.2020.104197
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000562074700008&DestApp=WOS_CPL
ID information
  • DOI : 10.1016/j.jece.2020.104197
  • ISSN : 2213-3437
  • eISSN : 2213-3437
  • Web of Science ID : WOS:000562074700008

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