煤矸石碱熔制备4A沸石

Preparation of 4A zeolite from coal gangue through a alkali fusion method

通过煤矸石加碱煅烧活化(碱熔),然后用水热合成的方法制备得到4A沸石。用XRD鉴定产品晶型、SEM观察结晶形貌,以钙交换值评价产品钙交换能力,并测定了产品的白度值,考察了晶化时间和活化效果对产品的影响。结果表明,煅烧过程升温速率为20℃/min时,老化2 h后,再晶化40 min即可得到结晶完整、不含杂晶的4A沸石产品,为4A沸石的立方体晶型,此时产品钙交换值(以CaCO3计)为312.0 mg/g。

4A zeolite was prepared by calcining activation of coal gangue together with solid caustic soda （alkali fusion） ; and followed by hydrothermal treatment of the calcined product. Crystalline form and the morphological characteristics of the product was identified and observed by XRD and SEM respectively. Ca2＋ exchange capacity and whiteness of the product was measured and evaluated. Influences of crystallizing time and effectiveness of calcining activation on the product quality was investigated. Results showed that after a calcining process with a temperature increasing rate of 20 ℃/min, followed by aging of 2 h and crystallization of 40 rain, a product of completely crystallized cubical crystalline form 4A zeolite and without impurities can be obtained. The Ca2＋ exchange capacity of the product achieves 312.0 mg/g.