以煤矸石为原料制备Al2O3-SiO2气凝胶的工艺与性能

煤矸石作为固体废弃物虽然被用作发电燃料、煤矿填料与建筑材料,但其利用率仍然不高,如何提高煤矸石的高值化利用率成为了目前研究的热点。本文以山西煤矸石为原料,采用一步酸溶和溶胶-凝胶法,并经过常压干燥得到了Al₂O₃-SiO₂气凝胶粉体。在溶剂置换与改性过程中引入超声波,研究了其对气凝胶的制备与性能的影响。采用BET、XRD、SEM、FT-IR、TG-DSC及接触角测试对所得Al₂O₃-SiO₂气凝胶粉体的结构与性能进行表征。结果表明,超声波的引入加快了反应速率,缩短了气凝胶的制备周期,所制备的Al₂O₃-SiO₂气凝胶是一种具有纳米三维网络结构的介孔材料,堆积密度低至0.120 g/cm³,比表面积为635 m²/g,高温下收缩性小于传统水玻璃制备的SiO₂气凝胶,并具有较好的疏水性。

Preparation and Properties of Al2O3-SiO2 Aerogel from Coal Gangue

Although coal gangue as solid waste is used in electricity generation,coalmine backfilling and building materials,its utilization rate is still not high.How to improve the high-value utilization of coal gangue has become a research hotspot.In this paper,Al₂O₃-SiO₂ aerogel powder was synthesized by one-step acid leaching followed by sol-gel method and ambient pressure drying from coal gangue.Ultrasonic was exerted in the process of solvent replacement and modification.The structure and performance of Al₂O₃-SiO₂ aerogel powder were characterized by means of BET,XRD,SEM,FT-IR,TG-DSC and contact angle measurement.The results show that the reaction rate is accelerated by ultrasonic and the preparation cycle is shortened.Al₂O₃-SiO₂ aerogel is a mesoporous material with three-dimensional network structure of nano.Al₂O₃-SiO₂ aerogel has a minimum bulk density of 0.120 g/cm³ and a specific surface area of 635 m²/g,its shrinkage at high temperature is lower than that of SiO₂ aerogel prepared from sodium silicate,Al₂O₃-SiO₂ aerogel also shows high hydrophobicity.