煤气化炉渣对煤矸石膏体充填材料性能影响

Effect of coal gasification slag on the properties of gangue gypsum filling materials

目的利用煤气化炉渣颗粒的球形特征,研究其对煤矿采空区膏体充填材料流动性和强度的影响规律,并分析其影响机理。方法以质量分数为85%的煤矸石骨料充填膏体为对照组,煤气化炉渣等质量取代膏体中煤矸石细骨料10%,20%,30%,40%,50%,分别测试新拌膏体泌水率、坍落度、扩展度、流变屈服应力和塑性黏度等浆体性能,同时测试膏体结石体抗压强度。结果结果表明,随着炉渣取代率增加,膏体泌水率增加,坍落度和扩展度增加,流变屈服应力和塑性黏度减小;与对照组相比,炉渣取代率为10%时,膏体屈服应力和塑性黏度分别降低16.7%,1.6%;与10%取代组相比,炉渣取代率为20%时,膏体屈服应力和塑性黏度分别降低47.4%,15.0%,降低速率大幅增加;继续增加炉渣取代率,膏体屈服应力和塑性黏度又缓慢增加;膏体结石体早期强度(3,7 d)随着炉渣取代率增加而小幅降低,后期强度(28,60 d)无显著变化。结论煤气化炉渣作为骨料取代膏体充填材料中的煤矸石细骨料,可以改善新拌膏体流动性,取代率达到20%时,可以充分发挥球状炉渣颗粒在多棱角煤矸石骨料间的滚珠润滑作用,减小矸石骨料机械咬合,大幅降低充填膏体屈服应力和塑性黏度;且炉渣对充填膏体结石体后期强度无显著影响。

Objective By utilizing the spherical characteristics of coal gasification slag particles,this study investigates their influence on the flowability and strength of coal mine goaf paste backfilling materials,and analyzes their influencing mechanisms.Methods Used coal gangue aggregate backfill paste with a mass concentration of 85%as the control group.The backfill paste fine coal gangue aggregate was replaced by the slag by 10%,20%,30%,40%,50%.The bleeding rate,slump,expansion,rheological yield stress,and plastic viscosity of the freshly mixed paste were tested separately.The compressive strength of the paste stone body was tested simultaneously.Results The results showed that with the increased of the slag replacement rate, the bleeding rate of the paste increased,the slump and elongation increased,and the rheological yield stress and plastic viscosity decreased.Compared with the control group,when the slag replacement rate was 10%, the yield stress and plastic viscosity of the paste decreased by 16.7% and 1.6%,respectively.Compared with the 10% substitution group,when the slag substitution rate was 20%,the yield stress and plastic viscosity of the paste are reduced by 47.4% and 15.0%,respectively.The rate of decrease significantly increases.As the slag replacement rate continued to increase,the yield stress and plastic viscosity of the paste gradually rose noe move.The early strength (3,7 d) of the paste stone body slightly decreased with the increased of the slag replacement rate,while there was no significant change in the later strength (28,60 d). Conclusion The coal gangue fine aggregate in the paste filling material was replaced by coal gasification slag,which could improve the flowability of the fresh paste.When the substitution rate reached 20%,the ball shaped slag particles could fully exert the ball lubrication effect between the multi edged coal gangue aggregates,reduced the mechanical bite of the gangue aggregates,and significantly reduce the yield stress and plastic viscosity of the filling paste.And the slag had no significant effect on the later strength of the backfilling paste stone body.