煤矿采空区膏体充填材料制备试验研究

Experimental study on paste filling material preparation in coal mine goaf

以煤矸石和粉煤灰为原料、电石渣为外加剂,通过试验得到了适合内蒙古乌海某煤矿采空区膏体充填材料的优势配比。保持充填浆料的质量浓度为67%,当煤矸石、粉煤灰、水泥和外加剂的质量比为14∶10∶2∶3时所形成的充填体,28 d单轴抗压强度为5.71 MPa,可以满足该矿最低充填强度的需求。试验中采用外加剂中的氢氧化钙作为碱性激发剂,用以激发粉煤灰的活性;选用的粉煤灰含有大量的硫酸钙,会和氢氧化钙与活性氧化铝发生反应生成钙矾石,产生胶凝作用,从而形成良好的充填强度。

With coal gangue and fly ash as raw materials and carbide slag as additive,the superior proportion of paste filling material suitable for a coal mine goaf in Wuhai of Inner Mongolia was obtained through experiments.The mass concentration of the filling slurry was kept at 67%,and when the mass ratio of gangue,fly ash,cement and additive of the filling body was 14∶10∶2∶3,its 28-day uniaxial compressive strength was 5.71 MPa,which could meet the minimum filling strength requirement of the mine.In the experiment,Ca(OH)2 in additive was used as basic activator to stimulate the activity of fly ash,furthermore,the fly ash selected in the experiment contained a large amount of CaSO4,which would react with Ca(OH)2 and active Al2O3 to form ettringite and produce cementation,thus forming good filling strength.