碳质高岭石合成NaA型沸石的研究(Ⅱ)——低温水热法人工合成NaA型沸石及其机理探讨

SYNTHESIS OF NaA-ZEOLITE FROM CARBONACEOUS KAOLINITE(Ⅱ) LOW TEMPERATURE SYNTHESIS OF NaA-ZEOLITE UNDER THE HYDROTHERMAL CONDITIONS AND THE SYNTHETIC MECHANISM

本研究采用碳质高岭石(陕西蒲白5号煤夹矸)作为起始原料,经脱碳活化处理后所得的白土在氢氧化钠碱性溶液中进行低温水热反应人工合成NaA型沸石。较适宜的合成条件为:H_2O/Na_2O=40～55,Na_2O/SiO_2=1,胶凝60℃、2h,晶化90℃、3h。综合晶化过程中固相的微观形貌观察、红外光谱分析和液相组份变化的测定结果,可以认为:利用碳质高岭土(蒲白5号煤夹矸)经水热反应合成NaA型沸石的机理为液相转化机理。

NaA-zeolite could be hydrothermally synthsized in NaOH liquor from the carbonaceous kaolinite as No.5 gangue at Pubai in Shannxi province, which must be decarbonized and activated under 850℃, 6h suitably. The synthetic condition of H_2O/Na_2O=40～55 (molar ratio), Na_2O/SiO_2=1, gelatinization: 60℃. 2h; crystallization; 90℃, 3h. The crystal growth processes of NaA-zeolite had been studied by means of SEM and Infrared Ray, it seems to be the synthetic mechanism of liquidus transition.