Kamara Saidu, Wei Wang, Ai Chaoqian
Department of Chemical Engineering, School of Water Resources and Environment, Chang'an University, Xi'an 710054, China.
Key Laboratory of Subsurface Hydrology and Ecology in Arid Areas, Ministry of Education, Chang'an University, Xi'an 710054, China.
Materials (Basel). 2020 Aug 2;13(15):3406. doi: 10.3390/ma13153406.
Coal fly ash and kaolin are ceramic compounds utilized as raw materials in the production of refractories. Fly ash is an environmental pollutant that emanates abundantly from coal thermal power plants. The management of the large amounts of fly ash produced has been very challenging, with serious economic and environmental consequences. Kaolin, on the other hand, is a natural and synthetic clay material used in medicines, paper, plastics, and cosmetic preparations. In this research, refractory materials (cordierite (MgAlSiO), mullite (3AlO·2SiO), and kyanite (AlSiO)) were fabricated in four different experiments, and an assessment was made of the strength of each of the materials. Coal fly ash and kaolin were each blended with alumina as starting materials. MgO and AlF·3HO were each applied as additives to the reacting materials. The mixtures were molded and sintered at temperatures between 1000 °C and 1200 °C for three hours in a muffle furnace, and characterized by SEM and XRD. The analysis revealed the evolution of cordierite, mullite, and kyanite alongside other crystalline compounds. The formation of kyanite in experiment C, due to the addition of AlF·3HO, is unprecedented and phenomenal. The XRD figures show the corundum phases crystallize at 1100 °C in experiments A and B, and disappear at 1200 °C.
煤粉煤灰和高岭土是用作耐火材料生产原料的陶瓷化合物。粉煤灰是一种从煤炭热电厂大量排放的环境污染物。管理大量产生的粉煤灰一直极具挑战性，会带来严重的经济和环境后果。另一方面，高岭土是一种天然和合成的粘土材料，用于医药、纸张、塑料和化妆品制剂。在本研究中，通过四个不同的实验制备了耐火材料（堇青石（MgAlSiO）、莫来石（3AlO·2SiO）和蓝晶石（AlSiO）），并对每种材料的强度进行了评估。分别将煤粉煤灰和高岭土与氧化铝作为起始原料进行混合。分别将MgO和AlF·3HO作为添加剂添加到反应材料中。将混合物在马弗炉中于1000℃至1200℃的温度下模压并烧结3小时，并通过扫描电子显微镜（SEM）和X射线衍射（XRD）进行表征。分析揭示了堇青石、莫来石和蓝晶石以及其他结晶化合物的演变情况。在实验C中，由于添加了AlF·3HO而形成蓝晶石，这是前所未有的且非常显著。XRD数据表明，在实验A和B中，刚玉相在1100℃结晶，并在1200℃消失。
