基于KCl-NaCl-K_(2)SO_(4)三元熔盐低温制备片状氧化铝

The Preparation of Platelet Alumina Based on KCl-NaCl-K_(2)SO_(4)Ternary Molten Salts at Low Temperature

以KCl、NaCl和K_(2)SO_(4)三元熔盐作为反应介质,AlF_(3)为添加剂,Al(OH)_(3)作为铝源,制备片状Al_(2)O_(3),并使用X射线衍射和扫描电子显微镜分别对制备的片状Al_(2)O_(3)的晶体构型和形貌进行了表征。分别研究了焙烧温度、AlF_(3)含量和焙烧时间对Al_(2)O_(3)形貌和晶体构型的影响,研究结果显示,当原料配比(质量比)w(KCl)∶w(NaCl)∶w(Na_(2)SO_(4))=1∶2∶2,AlF_(3)添加量为5 wt%(相对于Al(OH)_(3))时,在700℃煅烧240 min,即可获得分散性良好的、晶体构型为α型的片状Al_(2)O_(3),其平均径向尺寸约为5μm,平均厚度约为150 nm,径厚比约为33。

The platelet alumina was prepared with the KCl-NaCl-K_(2)SO_(4)ternary molten salts system as reaction medium,AlF_(3) as additive and Al(OH)_(3) as an aluminum source.The crystal structure and morphology of the prepared platelet alumina were characterized by XRD and SEM,respectively.Furthermore,the influences of calcining temperature,AlF_(3) content and calcining time on morphology and crystal structure of the alumina were studied.The results showed that with a raw material ratio(mass ratio)of w(KCl)∶w(NaCl)∶w(Na_(2)SO_(4))=1∶2∶2,AlF_(3) addition of 5 wt%(relative to Al(OH)_(3)),calcination at 700℃for 240 minutes,and well-dispersedα-phase platelet alumina were obtained;meanwhile,their mean radial size and thickness were respectively about 5μm and 150 nm,and their diameter-thickness ratio reached about 33.