高岭土类煤矸石的热活化性能

Pozzolanic activity of thermal activating coal gangue with kaolin clay composition

为了确定某高岭土类煤矸石热活化的工艺参数,采用差热-热重联用分析仪对破碎为4个不同粒级的煤矸石颗粒进行了热分析试验。利用X衍射仪、扫描电子显微镜和能谱仪研究了受Ca(OH)2激发后不同龄期热活化煤矸石的内部特征。研究结果表明:提高煤矸石的粒度将显著增加高岭土结晶相向无定形态的转变温度;激发早期煤矸石内部晶体相为Ca(OH)2,28d后则转变为水化硅铝酸钙和易变硅钙石等;颗粒表面非结晶相区域的化学成分1d时无明显改变,28d后钙硅物质的量的比增加而56d后则降低;随激发时间的延长,体系中Ca(OH)2的量28d前快速降低,其后逐渐平稳;将粒径控制在0.15～0.30mm之间,煅烧时间为1.5～3.0h,该煤矸石可形成较高的化学活性。

To determine the technical parameters in thermal activating coal gangue （TACG）, thermogravinmetric-differential scanning calorimeter ~TG-DSC） was used to explore transition temperature from crystalline of kaolin clay to amorphous state in coal gangues divided into four si- zes. Properties of TACG were studied using Ca （OH）2 consumption by X-ray diffraction, scan- ning electron microscopy and energy dispersive spectroscopy. The results show that the transition temperature is improved with increase of granules size. Ca （OH）2 crystals are discovered in TACG at the early period, however, replaced by stratlingite and tacharanite after 28 days in the process of Ca （OH）2 consumption experiment. The molar ratios of Ca/Si increase after 28 days and then decrease after 56 days on the surface of amorphous phase of TACG. With prolongation of time, Ca （OH）2 in the system containing TACG with Ca （OH）2 remarkably decreases before 28 days, compared with stable consumption after 28 days. Higher chemical activity is found as size of TACG is in the range of 0.15 to 0.30 mm with calcination time of 1.5 to 3.0 hours at 650 C. 5 tabs, 7 figs, 9 refs.