School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China; Key Laboratory of High-efficient Mining and Safety of Metal Mines, Ministry of Education, Beijing 100083, China.
School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China; Key Laboratory of High-efficient Mining and Safety of Metal Mines, Ministry of Education, Beijing 100083, China.
J Hazard Mater. 2021 Aug 5;415:125625. doi: 10.1016/j.jhazmat.2021.125625. Epub 2021 Mar 12.
This study focused on classifying and disposing Circulating fluidized bed (CFB) fly ashes from the level of its origin, and proposed an optimal formulation system for clinker-free cemented backfill materials. CFB fly ash-blast furnace slag (BFS)-based cemented backfill materials with unequal strength grades are used in different locations of the goaf that require more than 1 Mpa and 4 Mpa, respectively, and the leaching levels of all toxic components are lower than the underground III water quality standard limit when the additional amount of CFB fly ash does not exceed 60 wt.%. The stable S/S of Cl is due to the combined effect of chemical fixation of HCC and physical adsorption of the C-S-H/C-A-S-H phase. B2(20 wt.% CFB fly ash) exhibits more functional hydration products and higher degree of polymerization with the hydration age extension. Ettringite is the major effective product of CFB fly ash-BFS-based cemented system due to low level of chlorine environment and HCC transformation. CFB fly ash with appropriate active AlO can dissolve and promote [AlO] to substitute [SiO] to form the C-A-S-H phase with longer chains and higher degree of polymerization with increase in Al/Si ratio of C-A-S-H/C-S-H phase.
本研究从来源角度对循环流化床（CFB）飞灰进行分类和处置，并提出了一种无熟料水泥胶结充填料的最优配方体系。CFB 飞灰-矿渣（BFS）基胶结充填料在采空区的不同位置使用，分别需要超过 1MPa 和 4MPa 的强度等级，当 CFB 飞灰的添加量不超过 60wt.%时，所有有毒成分的浸出水平均低于地下 III 类水质标准限值。Cl 的稳定 S/S 是由于 HCC 的化学固定和 C-S-H/C-A-S-H 相的物理吸附的共同作用。B2（20wt.% CFB 飞灰）随着水化龄期的延长表现出更多的功能水化产物和更高的聚合度。由于低氯环境和 HCC 转化，钙矾石是 CFB 飞灰-BFS 基胶结系统的主要有效产物。具有适当活性 AlO 的 CFB 飞灰可以溶解并促进[AlO]取代[SiO]形成具有更长链和更高聚合度的 C-A-S-H 相，随着 C-A-S-H/C-S-H 相的 Al/Si 比增加。
