Abstract:

The 4A zeolite molecular sieve [Na12 (Al12Si12O48) ·27H2O] was synthesized in a sealed Teflon lined autoclave by hydrothermal reaction of NaOH solution and metakaolinite (the mass ratio of solid/liquid is 1∶20) prepared by calcined coal-measure kaolin from Xuzhou at 550℃ for 2h. 4A zeolite molecular sieve was characterized by X-ray diffraction (XRD)，Fourier transform infrared spectroscopy (FT-IR)，scanning electron microscopy (SEM) and N2 adsorption and desorption isotherm plot methods. The results indicated that amorphous anhydrous metakaolinite was obtained by calcination of kaolin at 550℃ for 2h; it was transformed to 4A zeolite molecular sieve by alkali leaching; the best concentration of NaOH solution was 2mol/L; the pore channel of 4A zeolite molecular sieve was long and narrow，but its shape and size were not uniform.

摘要：

研究以徐州地区煤系高岭土为原料、NaOH溶液为浸取液，先于550℃煅烧2 h得到偏高岭土，再在全密封反应釜中通过偏高岭土和NaOH溶液（固液质量比1∶20）之间的水热反应制备4A沸石分子筛[Na12(Al12Si12O48)·27H2O]。并采用X射线衍射仪（XRD）、傅里叶转换红外光谱仪（FT-IR）、扫描电子显微镜（SEM）和N2吸附脱附等测试手段对4A沸石分子筛进行表征。结果表明，煤系高岭土经550 ℃煅烧2 h后转变成无定形态的偏高岭土，碱浸取后变成4A沸石分子筛；合成4A沸石分子筛过程中NaOH溶液的最佳浓度是2 mol/L；4A沸石分子筛具有狭缝状孔道，但孔的形状和分布不均匀。