Removal of metallic Al and Al/Zn alloys in MSWI bottom ash by alkaline treatment

Dongxing Xuan, Chi Sun Poon

Research output: Journal article publicationJournal articleAcademic researchpeer-review

26 Citations (Scopus)

Abstract

In order to reduce the leaching of pollutants and remove the Al and Zn/Al alloy from municipal solid waste incineration bottom ash (MSWIBA), an optimized alkaline pre-treatment procedure was developed in this study. The influences of alkaline conditions on the removal rate of Al and Zn/Al alloy were investigated, including [OH]−concentration, temperature, particle size, liquid/solid ratio and treatment duration. The experimental results showed that the optimized alkaline pre-treatment conditions to efficiently remove the Al and Zn/Al alloy was by using a minimum of 1.0 mol/l [OH]−, at 55 °C and with a minimal liquid/solid ratio of 5. The removal rate of Al and Zn/Al alloy followed an S-shape curve, in which the slow beginning stage was attributed to the protection of the oxidation layer and the quenched product around the Al and Al/Zn alloy. After 3 h of the optimized alkaline pre-treatment, the leaching of Cr, Cu, Pb and Zn of the treated MSWIBA was reduced by more than 90% of that of the original MSWIBA. The alkali-silica reaction test further indicated that the expansion of concrete prepared with the pre-treated MSWIBA was significantly reduced and there was no macro-crack or spalling damage on the surface of the tested specimens.
Original languageEnglish
Pages (from-to)73-80
Number of pages8
JournalJournal of Hazardous Materials
Volume344
DOIs
Publication statusPublished - 1 Jan 2018

Keywords

  • Alkali-silica effect
  • Alkaline treatment
  • Heavy metals
  • Incineration bottom ash
  • Metallic Al and alloy

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis

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