Xiao Bolin, Wang Jiandong, Wu Aixiang, Guo Ruiming
State Key Laboratory of High-Efficient Mining and Safety of Metal Mine Ministry of Education, University of Science and Technology Beijing, Beijing 100083, China.
School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China.
Gels. 2024 Sep 27;10(10):623. doi: 10.3390/gels10100623.
As more and more mines utilize the cemented paste backfill (CPB) mining method, the demand for reducing backfill cost and carbon footprint is increasing and becoming more critical. In this work, a new backfill gel binder made with 40 wt.% of low-quality Class F fly ash (FCM) is proposed to replace ordinary Portland cement (OPC). The binder hydration and gel hardening properties were experimentally investigated through X-ray diffraction, Mercury intrusion porosimetry, uniaxial compression, and thermogravimetric analysis. Three different mine tailings were used to verify the FCM's applicability. Results show that the strength performance of FCM-CPB is 72% of that of OPC-CPB, while FCM production cost is almost less than half of OPC. The hydration process of the FCM-CPB can be divided into five stages, and the main hydration products are ettringite and gel-like hydrates. The 31.2% porosity of FCM-CPB at 28-day curing is higher than that of 7-day curing, while the average pore size is lower, and the structure is denser. The FCM can meet the strength requirement of three different mine tailings regarding different subsequent filling and cut-and-fill mining methods. The proposed FCM provides a feasible alternative with economic and environmental benefits.
随着越来越多的矿山采用胶结膏体充填（CPB）采矿方法，降低充填成本和碳足迹的需求日益增加且愈发关键。在这项工作中，提出了一种由40 wt.%的低品质F类粉煤灰（FCM）制成的新型充填胶凝材料来替代普通硅酸盐水泥（OPC）。通过X射线衍射、压汞法、单轴压缩和热重分析等实验研究了该胶凝材料的水化和凝胶硬化性能。使用三种不同的尾矿来验证FCM的适用性。结果表明，FCM-CPB的强度性能为OPC-CPB的72%，而FCM的生产成本几乎不到OPC的一半。FCM-CPB的水化过程可分为五个阶段，主要水化产物是钙矾石和凝胶状水化物。FCM-CPB在养护28天时的孔隙率为31.2%，高于养护7天时的孔隙率，而平均孔径更小，结构更致密。FCM能够满足三种不同尾矿对于不同后续充填和上向分层充填采矿方法的强度要求。所提出的FCM提供了一种具有经济和环境效益的可行替代方案。
