Effect of CO 2 Mineralization on the Composition of Alkali-Activated Backfill Material with Different Coal-Based Solid Wastes

Binbin Huo, Jixiong Zhang (), Meng Li, Nan Zhou, Xincai Qiu, Kun Fang () and Xiao Wang
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Binbin Huo: School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Jixiong Zhang: School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Meng Li: State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou 221116, China
Nan Zhou: School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Xincai Qiu: Jining Energy Bureau, Jining 272067, China
Kun Fang: School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Xiao Wang: School of Mines, China University of Mining and Technology, Xuzhou 221116, China

Sustainability, 2023, vol. 15, issue 6, 1-13

Abstract: Research focusing on waste management and CO 2 mineralization simultaneously has been a popular topic in the mining community, and a common approach is to mineralize CO 2 with coal-based solid waste (CSW, e.g., gangue (CG), fly ash (FA), coal gasification slag (CGS)) produced by mining activities. Despite the understanding of CO 2 mineralization by cementitious materials, the mineralization capacity of alkali-activated CSWs remains unknown. Therefore, the mineral composition evolution and mineralization capacity of different alkali-activated materials (prepared with CG, FA, CGS, and sodium hydroxide (which works as the alkali-activator), respectively) are investigated with the adoption of Gibbs Energy Minimization Software (GEMS). The results indicate that the abovementioned three alkali-activated CSWs are majorly composed of calcium silicate hydrate, magnesium silicate hydrate, kaolinite, sodium zeolite, and liquid. Due to the difference in the chemical composition of different CSWs, the amount of hydration products varies. Specifically, the alkali-activated CSWs made with CGS have the maximum calcium silicate hydrate (C-S-H), while those prepared with FA enjoy the lowest porosity. In addition, the CO 2 mineralization process will result in the formulation of carbonate and, theoretically, the maximum quantity of mineralized CO 2 is less than 20% of the binder used. Furthermore, compared with CG and CGS, FA is characterized with the highest mineralization capacity. The findings in this study contribute to the understanding of CO 2 mineralization with alkali-activated CSWs.

Keywords: coal-based solid waste; coal mining; backfill; alkali-activated materials; CO 2 mineralization (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2023
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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