Stabilisation/solidification of municipal solid waste incineration fly ash by phosphate-enhanced calcium aluminate cement

Liang Chen, Yan Shuai Wang, Lei Wang, Yuying Zhang, Jining Li, Lizhi Tong, Qing Hu, Jian Guo Dai, Daniel C.W. Tsang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

22 Citations (Scopus)


Landfill disposal of municipal solid waste incineration fly ash (MIFA) presents significant environmental and economic burden. This study proposed a novel and high-efficiency approach for stabilisation/solidification (S/S) of MIFA by phosphate-modified calcium aluminate cement (CAC). Experimental results showed that the presence of Pb (the most leachable metal contaminant in the MIFA) retarded the early-stage reaction of CAC, resulting in an extension of setting time and a significant decline of compressive strength of CAC pastes. The incorporation of phosphate additives (10 wt% of binder), especially for trisodium phosphate, in CAC system effectively mitigated the negative impact of Pb on the CAC reaction and reduced the Pb leachability. Elemental mapping results illustrated that Pb2+ coordinated with phosphate to generate insoluble precipitates (e.g., Pb3(PO4)2). The S/S treated MIFA samples fulfilled the compressive strength and leachability requirements for on-site reuse. Overall, this study demonstrated that phosphate-modified CAC is a promising binder for S/S of hazardous MIFA.

Original languageEnglish
Article number124404
JournalJournal of Hazardous Materials
Publication statusAccepted/In press - 2020


  • Green and sustainable remediation
  • Hazardous waste treatment
  • High-alumina cement
  • Metal leachability
  • Phosphate additives

ASJC Scopus subject areas

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

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