Preparation and properties of modified coal gasification slag⁃based filling materials for mines
QU Huisheng,SUO Yonglu,LIU Lang,ZHOU Wenwu,YANG Pan,ZHANG Caixin
为研究煤矸石(CG) 和煤气化粗渣(CS)用于膏体胶结充填的可行性,使用 Talbol 级配理论对骨料进行粒径控制,少量硅酸盐水泥作为胶凝材料,大量 CS 作为辅助胶凝材料,做了多组 CG、 CS、水泥、激活剂的不同配比实验。 实验内容包括 4 个部分:骨胶比,总固体质量分数,激活剂质量分数以及其对凝结时间、流动性、泌水率、收缩率的影响和最佳配比的浸出实验。 使用 X 射线荧光光谱分析、单轴抗压强度、自然堆积密度、塌落度、SEM-EDS,X 射线衍射等手段分析了煤矸石-煤气化渣胶结充填体(CCCPB)的充填性能。 实验结果表明:1 受级配和水化程度影响,骨料掺量为20%时,其 3 d 和 7 d 的强度都达到最大值,28 d 强度为 6.7 MPa;2 总固体质量分数对强度和流动性影响十分明显,且高水环境更有利于硫酸钠对 CCCPB 的激发效果;3 硫酸钠可显著激发 CS 活性,3 d 和 7 d 水化产物主要是氢氧化钙和水化硅酸钙,28 d 时生成大量钙矾石,且随硫酸钠质量分数增加,充填体早期生成了更多的水化产物,在 28 d 龄期内并未出现强度折减现象;4 随硫酸钠质量分数增加,凝结时间逐渐缩短,对终凝时间影响更为显著;塌落度、扩展度经时损失量逐渐增大;泌水率、收缩率逐渐减小,以硫酸钠质量分数 2%为界限,各参数变化速率逐渐减小,且总固体质量分数对初始流动性的影响大于硫酸钠质量分数;5 在最佳配比:骨胶比 2 ∶ 8,总固体质量分数80%,硫酸钠质量分数 2%时,各类重金属浸出量均低于国家标准,满足环保要求。 基于上述研究,可以推断出 CCCPB 完全可以在充填开采中被使用。
In order to study the feasibility of coal gangue (CG) and coal gasification coarse slag (CS) for paste ce⁃ ment filling,the Talbol grading theory is used to control the particle size of aggregate,a small amount of Portland ce⁃ ment is used as a cementing material,and a large amount of CS is used as an auxiliary cementing material. Based on above,a multiple sets of experiments with different proportions of CG,CS,cement and activator have been conducted.The experiment content includes four parts:aggregate⁃glue ratio,mass concentration,activator content and its influence on setting time,fluidity,bleeding rate,shrinkage rate and the best ratio of leaching experiment. Using X⁃ray fluores⁃ cence spectrometry,uniaxial compressive strength,natural bulk density,slump,SEM-EDS,X⁃ray diffraction and oth⁃ er methods,the filling performance of coal gangue⁃coal gasification slag cemented backfill (CCCPB) was analyzed. Experimental results show:1 affected by the gradation and hydration degree,when the aggregate content is 20%,the uniaxial compressive strengths of the CCCPB after 3 d and 7 d reach the maximum, 28 d UCS is 6. 7 MPa. 2 The mass concentration has a significant impact on the strength and fluidity of the CCCPB,and the high water envi⁃ ronment is more conducive to the stimulation effect of Na2 SO4 on the CCCPB. 3 Na2 SO4 can significantly stimu⁃ late the activity of CS. The hydration products of 3 d and 7d are mainly Ca(OH)2 and calcium silicate hydrate. A large amount of ettringite will be generated at 28 d,and with the increase of Na2SO4 content,more hydration products are generated in the early filling body,and there is no strength reduction phenomenon during the 28 d age. 4 With the increase of Na2SO4 content,the setting time is gradually shortened,and the effect on the final setting time is more sig⁃ nificant. The loss of slump and spreading degree gradually increases with time. The bleeding rate and shrinkage rate gradually decrease,with 2% content as the limit,the rate of change of each parameter gradually decreases,and the influence of mass concentration on initial fluidity is greater than the Na2 SO4 content. 5 When the optimal ratio:aggre⁃ gate⁃to⁃glue ratio is 2 ∶ 8,mass concentration is 80%,and Na2 SO4 content is 2%,the leaching amount of various heavy metals is lower than the national standard and meets the environmental protection requirements. Based on the above research,it can be concluded that the CCCPB can be used in mine filling.
coal gasification coarse,filling material,best ratio,hydration products,Na2SO4
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会