In order to promote the resource utilization of coal gasification slag (CGS) solid waste, the use of modified coal gasification slag (MCGS) to replace the cement in the cemented backfill materials is an effective way to improve the utilization rate of CGS resources, reduce the backfill cost and reduce the environmental pollution of the cement industry. In this paper, the dosage of sodium sulfate (SS) in the MCGS cemented backfill materials (MCGS-CB) system composed of MCGS–cement–aeolian sand is optimized, and the curing mechanism of MCGS-CB under the action of SS is revealed. The results show that the addition of MCGS delays the early hydration reaction process, accelerates the consumption of sulfate in the system, and shows the phenomenon of sulfate deficiency; The pozzolanic reaction of MCGS increased the ratio of Al/Ca, Si/Ca, S/Ca and Na/Ca of hydration products, changed the structure of hydration products, promoted the formation of hydration products such as C-S(A)-H, C-N-S(A)-H and AFt, increased the density of matrix, reduced the pore volume of harmful pores, and increased the compressive strength. Under the action of SS, the hydration reaction process of the early MCGS-CB was accelerated, the time of the sulfate depletion (SD) point was delayed, and the reaction time of the MCGS was advanced; The consumption of Al and Si ions drives the dissolution of the aluminosilicate glass body in the MCGS, thereby further promoting the formation of hydration products such as C-S(A)-H, C-N-S(A)-H and AFt, and increasing its matrix compactness. About 4% SS has a good excitation effect on MCGS, and excessive SS addition will cause microcracks in MCGS-CB, resulting in a reduction in strength. The results of this study can provide theoretical guidance for the ratio design and field application of sulfate-coal gasification slag-cement cementation system.

为促进煤气化渣（CGS）固废资源化利用，采用改性煤气化渣（MCGS）替代胶结回填材料中的水泥，是提高煤气化渣资源利用率、减少回填成本，减少水泥行业的环境污染。本文对MCGS-水泥-风积砂组成的MCGS胶结回填材料（MCGS-CB）体系中硫酸钠（SS）的用量进行了优化，揭示了MCGS-CB在SS作用下的固化机理。 . 结果表明，MCGS的加入延缓了早期水合反应过程，加速了体系中硫酸盐的消耗，出现了缺硫酸盐现象；这MCGS的火山灰反应增加了水合产物的Al/Ca、Si/Ca、S/Ca和Na/Ca比，改变了水合产物的结构，促进了CS(A)-H、CNS等水合产物的形成(A)-H和AFt，增加了基体的密度，减少了有害孔隙的孔容，提高了抗压强度。在SS的作用下，早期MCGS-CB的水合反应过程加快，硫酸盐耗尽（SD）点的时间延迟，MCGS的反应时间提前；Al和Si离子的消耗驱动MCGS中的铝硅酸盐玻璃体溶解，从而进一步促进CS(A)-H、CNS(A)-H和AFt等水合产物的形成，提高其基体致密性. 4%左右的SS对MCGS有很好的激发作用，SS添加过多会导致MCGS-CB产生微裂纹，导致强度降低。本研究结果可为硫酸盐-煤气化矿渣-水泥胶结体系配比设计和现场应用提供理论指导。