煤矸石热活化性能研究

Thermal activation of coal gangue

系统地研究了徐州夹河煤矸石在不同煅烧温度下的物理、化学变化及活性成分的溶出规律。采用扫描电子显微镜(SEM)、差热分析(DTA)、X射线衍射(XRD)等测试方法研究了热活化前后煤矸石的矿物组成、SiO2及Al2O3溶出率和微观结构,并采用水泥强度的测试方法对热活化煤矸石的活性进行宏观表征。结果表明,煅烧能有效去除有机挥发物和碳,破坏煤矸石中的硅氧键、铝氧键,形成无定形物质和玻璃相,从而提高煤矸石的活性。徐州夹河煤矸石的最佳热活化工艺条件是煅烧650℃、保温2h。经此条件热活化后,SiO2和Al2O3的最高溶出率分别是76.32%、91.48%,添加50%(质量分数)的热活化煤矸石到水泥中,其强度比同掺量原样煤矸石的水泥强度提高了230%。

The physicochemical transformations and dissolution of active ingredients of Jiahe coal gangue calcined at different temperatures were studied. The mineral composition, leaching data of silica and alumina, SEM, DTA, and XRD spectra were employed to analyze the microstructure of the raw and calcined coal gangue samples. Calcination of the raw coal gangue removed its water and organic contents, formed amorphous material and glass phase and made its SiO2 and A1203 contents much more soluble to result in a useful cement replacement material. 76.32% of silica and 91.48% of alumina of the activated Jiahe coal gangue, which was calcined at 650 ℃ for 2 h, were leached out by extraction with KOH and HCt, respectively. The compressive strength of the coal gangue cement containing 50% of the raw coal gangue improved more than 230% when the raw coal gangue was replaced by the activated coal gangue.