Purposes Coal gasification fine slag is a solid waste formed during the coal gasification process. Methods To improve its utilization rate, in this research, the substitution of part of cement with coal gasification fine slag was conducted. The setting time of paste, workability, and mechanical properties of the mortar were investigated. Besides, the hydration mechanism of the coal gasification fine slag-cement composite was analyzed by using isothermal calorimetry, XRD, scanning electron microscopy, and thermodynamic simulation. Results The results indicate that as the content of coal gasification fine slag increasing, the setting time of pure cement paste is prolonged, and the workability of the mortar gradually decreases. When the coal gasification fine slag content is 10%, the 28 d compressive strength of the mortar reaches the level of the control group. Adding an appropriate amount (not exceeding 10%) of coal gasification fine slag into cement-based materials reduces heat of hydration of cement, decreases cement consumption, and improves the utilization rate of coal gasification fine slag without significantly affecting the performance indicators of cement-based materials.
图6显示了砂浆在相同龄期的抗压强度。与抗折强度类似,随着养护龄期的增加,砂浆的抗压强度逐渐增大;随着煤气化细渣掺量增加,砂浆的抗压强度逐渐降低。不同的是,随着养护龄期的增加,C1的抗压强度十分接近C0。在3 d 时,C1的抗压强度相较于C0下降幅度最大,达到12.42%;在养护28 d后,二者差距仅为0.3%。C2的抗压强度相较于C0下降了24.3%~29.4%;C3的抗压强度相较于C0下降了47.6%~60.5%。可见,高掺量的煤气化细渣对砂浆的抗压强度影响更加显著。
ZhaoY, QiuJ, MaZ,et al.Eco-friendly treatment of coal gangue for its utilization as supplementary cementitious materials[J].Journal of Cleaner Production,2021,285:124834.
[3]
SkibstedJ, SnellingsR.Reactivity of supplementary cementitious materials (SCMs) in cement blends[J].Cement and Concrete Research,2019,124:105799.
YanS, XuanW, CaoC,et al.A review of sustainable utilization and prospect of coal gasification slag[J].Environmental Research,2023,238:117186.
[10]
SuS, TahirM H, ChengX,et al.Modification and resource utilization of coal gasification slag-based material:A review[J].Journal of Environmental Chemical Engineering,2024,12(2):112112.
DaiG, ZhengS, WangX,et al.Combustibility analysis of high-carbon fine slags from an entrained flow gasifier[J].Journal of Environmental Management,2020,271:111009.
ZhaoJ, ZhangX, ShengJ,et al.Utilization of coal gasification fine ash for construction material:From physical and chemical properties to the hydration activity of thermally modified CGFA[J].Journal of Environmental Chemical Engineering,2023,11(6):111137.
[15]
YamanakaY, FujiwaraH, MaruokaM,et al.Experimental study on properties of mortar containing molten slag as fine aggregate[J].Special Publication,2018,326:1-49.
MiaoZ, ChenL, ChenK,et al.Physical properties and microstructures of residual carbon and slag particles present in fine slag from entrained-flow coal gasification[J].Advanced Powder Technology,2020,31(9):3781-3789.
[20]
LiuJ, QiuJ, WuP,et al.Calcined oil shale residue as a supplementary cementitious material for ordinary Portland cement[J].Construction and Building Materials,2021,306:124849.
[21]
LiuJ, ZhaoJ, ZhaoY,et al.Resource utilization of solid waste from steel industries in cement-based cementitious materials:Mechanical properties,hydration behaviors,and environmental impact[J].Journal of Environmental Chemical Engineering,2023,11(3):109882.
YeF, QiaoH, FengQ,et al.Study on multi-performance optimization of basalt stone powder supplementary cementitious materials[J].Journal of Building Engineering,2023,80:108018.
ZhaoJ, LiuJ, WuY,et al.Application of an industrialized ultrafine composite powder in cement-based materials:Hydration characteristics,microstructure,and corrosion resistance[J].Construction and Building Materials,2024,411:134629.