Electrolytic manganese residue-based cement for manganese ore pit backfilling: Performance and mechanism

Jirong Lan, Yan Sun, Hong Tian, Wei Zhan, Yaguang Du, Hengpeng Ye, Dongyun Du, Tian C. Zhang, Haobo Hou

Research output: Contribution to journalArticlepeer-review

Abstract

Slag backfilling with electrolytic manganese residue (EMR) is an economical and environmentally-friendly method. However, high ammonium-nitrogen and manganese ions in EMRs limit this practice. In this study, a method of highly efficient simultaneous stabilization/solidification of ultrafine EMR by making EMR-based cementitious material (named EMR-P) was proposed and tested via single-factor and response surface optimization experiments. Results show that the stabilization efficiency of NH4+ and Mn2+ were above 95%, and the unconfined compressive strength of the EMR-P was 18.85 MPa (megapascal = N/mm2). The mechanistic study concluded that the soluble manganese sulfate and ammonium sulfate in EMR were converted into the insoluble precipitates of manganite (MnOOH), gypsum (CaSO4), MnNH4PO4·H2O, and struvite (MgNH4PO4∙6 H2O), leading to the stabilization of NH4+ and Mn2+ in the EMR-P. Leaching tests of EMR-P indicated that NH4+, Mn2+, and others heavy metals in the leachate were within the permitted level of the GB/T8978-1996. The novelty of this study includes the addition of phosphate and magnesium ions to precipitate ammonium-nitrogen and the combination between calcium ions (from CaHPO4∙2 H2O) and sulfate (from the EMR) to form calcium sulfate to improve the stability and unconfined compressive strength of cementitious materials (EMR-P).

Original languageEnglish (US)
Article number124941
JournalJournal of Hazardous Materials
Volume411
DOIs
StatePublished - Jun 5 2021

Keywords

  • Ammonium sulfate
  • Cement-based stabilization/solidification
  • Electrolytic manganese residue
  • Manganese ore pit backfilling
  • Manganese sulfate

ASJC Scopus subject areas

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

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