Simultaneous stabilization/solidification of Mn2+ and NH4+-N from electrolytic manganese residue using MgO and different phosphate resource

Ecotoxicol Environ Saf. 2018 Feb:148:220-227. doi: 10.1016/j.ecoenv.2017.10.027. Epub 2017 Nov 6.

Abstract

This study examined simultaneous stabilization and solidification (S/S) of Mn2+ and NH4+-N from electrolytic manganese residue (EMR) using MgO and different phosphate resource. The characteristics of EMR NH4+-N and Mn2+ S/S behavior, S/S mechanisms, leaching test and economic analysis, were investigated. The results show that the S/S efficiency of Mn2+ and NH4+-N could reach 91.58% and 99.98%, respectively, and the pH value is 8.75 when the molar ratio of Mg:P is 3:1 and the dose of PM (MgO and Na3PO4·12H2O) is 8wt%. In this process, Mn2+ could mainly be stabilized in the forms of Mn(H2PO4)2·2H2O, Mn3(PO4)2·3H2O, Mn(OH)2, and MnOOH, and NH4+-N in the form of NH4MgPO4·6H2O. Economic evaluation indicates that using PM process has a lower cost than HPM and HOM process for the S/S of Mn2+ and NH4+-N from EMR at the same stabilization agent dose. Leaching test values of all the measured metals are within the permitted level for the GB8978-1996 test suggested when the dose of PM, HPM and HOM is 8wt%.

Keywords: Electrolytic manganese residue; Leaching test; Phosphate resource; Stabilization/solidification.

MeSH terms

  • Ammonium Compounds / chemistry*
  • Electrolysis
  • Electrolytes
  • Ions
  • Magnesium Oxide / chemistry*
  • Manganese / chemistry*
  • Nitrogen / chemistry*
  • Phosphates / chemistry*
  • Refuse Disposal / methods*
  • Solid Waste / analysis

Substances

  • Ammonium Compounds
  • Electrolytes
  • Ions
  • Phosphates
  • Solid Waste
  • Magnesium Oxide
  • Manganese
  • Nitrogen