高铝粉煤灰脱硅液与煤矸石制备13X分子筛的工艺研究

Synthesis and Characterization of 13X Zeolite Prepared from Desilication Solution of High Alumina Fly Ash and Coal Gangue

以13X分子筛的低成本制备与煤基固废协同利用为目标,利用煤矸石与高铝粉煤灰碱法提铝过程中副产的脱硅液为原料,通过水热反应制备了13X分子筛,实现了两种固废资源的协同利用。考察了水热反应体系水钠比、硅铝比、晶化温度、搅拌速率等因素对合成产物晶型和比表面积的影响规律。通过X射线衍射、红外光谱和扫描电镜等方法对产物结构和形貌的演化过程进行了表征分析。结果表明,在优化工艺为n(SiO_2/Al_2O_3)=3.0,n(Na_2O/SiO_2)=1.9,n(H_2O/Na_2O)=60,室温下老化24 h,100 r·min^(-1)下于95℃水热晶化8 h制备的13X分子筛比表面积为681.7 m^2·g^(-1),相对结晶度94.59%。通过对水热反应过程分析,13X分子筛合成过程前期主要为煤矸石与脱硅液反应形成无定型凝胶,后期为凝胶相溶解和分子筛晶体的生长。

In this study,13 X zeolite was prepared through hydrothermal process from coal gangue and the desilication solution,a kind of by-productin the alumina extraction from high alumina coal fly ash,in order to realize the low cost preparation of 13 X zeolite and utilization of coal based solid waste. The effects of synthesis parameters,such as n（H2O/Na2O）,n（ SiO2/Al2O3）,reaction temperature and stirring rate on the crystal structure and the BET surface area of the product were studied. The products was characterized by X-ray diffraction（ XRD）,fourier transform infrared spectroscopy（ FTIR）,and scanning electron microscopy（ SEM）. As a result,the optimum synthesis conditions of 13 X zeolite is n（ SiO2/Al2O3） = 3. 0,n（ Na2O/SiO2） = 1. 9,n（ H2O/Na2O） = 60,after homogenization by aged at room temperature for 24 h,then crystallized at 95 ℃ for 8 h at 100 r·min^-1. At this condition,relative crystallinity 94. 59%,BET surface area up to 681. 7 m^2·g^-1 is achieved. According to the analysis ofthe hydrothermal synthesized process,13 X zeolite synthesis process is early mainly for coal gangue and desilication solution reaction form the amorphous gel,then gel phase dissolve and the growth of zeolite crystals.