贵州某煤矸石矿物学特征及胶凝活性激发研究

Study on Mineralogical Characteristics and Cementitious Activity Stimulation of a Gangue from Guizhou Province

以贵州某选煤厂排弃的煤矸石作为研究对象,开展煤矸石矿物学及胶凝活性激发研究。结果表明,煤矸石中煤和矸石嵌布粒度均较粗、相互包裹,含有大量高岭石、蒙脱石、伊利石、钠长石、绿泥石等铝硅酸盐矿物,SiO_(2)和Al_(2)O_(3)质量分数分别为47.08%和21.68%;未处理的煤矸石几乎无胶凝活性,随着焙烧温度升高,SiO_(2)和Al_(2)O_(3)溶出率逐渐增大,胶凝活性提升,在焙烧温度为500~800℃范围时达到最大;30%掺量煤矸石和70%掺量水泥作为胶凝材料制备混凝土,其抗压及抗折强度曲线均在焙烧温度为800℃附近出现最大值,主要是因为煤矸石中高岭石、石英等矿物分解产生的非晶态二氧化硅、氧化铝等在碱环境中生成地聚物胶凝材料。本研究可为煤矸石在混凝土中的资源化利用及煤矸石减量化提供参考。

The coal gangue from a coal preparation plant in Guizhou Province was taken as the research object to study the mineralogy of coal gangue and cementitious activity activation of coal gangue.The results show that the coal and gangue have coarse disseminated particle size and interlaid with each other.The coal gangue contains a lot of aluminosilicate minerals such as kaolinite,montmorillonite,illite,albite,chlorite,and so on.The content of SiO_(2) and Al_(2)O_(3) reaches 47.08%and 21.68%,respectively.The untreated gangue has almost no cementitious activity.With the increase of roasting temperature,the dissolution rates of SiO_(2) and Al_(2)O_(3) gradually increase and reach the maximum at 500 to 800℃.The compressive and flexural strength of concrete prepared with 30%coal gangue and 70%cement reaches a peak near 800℃,which is mainly due to the formation of geopolymer cementitious material in an alkali environment by amorphous silica and alumina generated from the decomposition of kaolinite,quartz and other minerals in coal gangue.This study provides a reference for the resource utilization of gangue in concrete and the reduction of gangue.