TY - JOUR
T1 - Electrolytic manganese residue-based cement for manganese ore pit backfilling
T2 - Performance and mechanism
AU - Lan, Jirong
AU - Sun, Yan
AU - Tian, Hong
AU - Zhan, Wei
AU - Du, Yaguang
AU - Ye, Hengpeng
AU - Du, Dongyun
AU - Zhang, Tian C.
AU - Hou, Haobo
N1 - Funding Information:
This work was financially supported by the National Sci-Tech Support Plan ( 2015BAB01B03 ); Major Innovation Projects of Hubei Province, P.C. China ( 2019ACA156 ) and National Natural Science Foundation of China ( 51804354 ), which are greatly appreciated; Also, we are highly thankful to Dr. Rao Y. Surampalli of the U.S. Environmental Protection Agency (USEPA) for his advises and supports on this study.
Publisher Copyright:
© 2021
PY - 2021/6/5
Y1 - 2021/6/5
N2 - 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).
AB - 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).
KW - Ammonium sulfate
KW - Cement-based stabilization/solidification
KW - Electrolytic manganese residue
KW - Manganese ore pit backfilling
KW - Manganese sulfate
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U2 - 10.1016/j.jhazmat.2020.124941
DO - 10.1016/j.jhazmat.2020.124941
M3 - Article
C2 - 33858079
AN - SCOPUS:85099616477
VL - 411
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
SN - 0304-3894
M1 - 124941
ER -