摘要:以不同地区的高岭石为原料,采用水热晶化法工艺合成了4A分子筛;利用X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和热分析(TG-DSC)等方法对4A分子筛的结构和热稳定性进行了分析,研究了不同结晶度高岭石制备4A分子筛的机理。结果表明:来自不同地区的高岭石的结晶度由高到低的顺序为张家口、塔山、哈尔乌素、不连沟;结晶度较好的高岭石在活化时均需要较高的温度;当煅烧温度为800℃、晶化温度为95℃、晶化时间为6 h时,4A分子筛具有良好的骨架和热稳定性。
关键词:高岭石;结晶度;4A分子筛;水热晶化法
Abstract: A kind of 4A molecular sieve was synthesized from kaolinite obtained from different regions by hydrothermal crystallization.The structure and thermal stability of the 4A molecular sieve were analyzed by means of X-ray diffraction ( XRD) ,Fourier transform infrared spectroscopy ( FTIR) and thermal analysis ( TG-DSC) .The results showed that the order of crystallinity of kaolinite from different regions from high to low was as follows Zhangjiakou,Tashan,Haerwusu,Buliangou.The activation of kaolinite with good crystallinity requires higher temperature.When the optimum calcination temperature is 800 ℃,crystallization temperature is 95 ℃ and crystallization time is 6h,the 4A molecular sieve zeolite has good skeleton and thermal stability.
Keywords: kaolinite; crystallinity; 4A molecular sieve; hydrothermal crystallization