利用粉煤灰中溶出的硅、铝定向合成沸石

基于水热合成沸石条件下研究获得的内蒙古乌海乌云电厂粉煤灰和呼和浩特呼一电厂粉煤灰中硅、铝的溶出规律,添加适量外源硅、铝调配硅铝比,采用水热合成法定向合成A型和X型沸石,采用XRD鉴定了合成产物,考察了碱度对沸石合成的影响.结果表明:两种粉煤灰中硅的溶出量随时间延长而增加,而铝的溶出量先增加后减小,可溶出的硅、铝量远小于粉煤灰组成中的硅、铝含量;碱度的增加有利于A型沸石晶核的形成和生长;此外,还定向合成了X型沸石.论文研究证实,水热合成条件下粉煤灰中溶出的有效硅、铝才是合成沸石时可利用的有效成分,以溶出的硅铝量指导水热合成,可定向合成出多型沸石.

Directional synthesis of zeolites with silicon and aluminum dissolved from fly ash

Two fly ashes were sampled from Wuhai Wuyun power plant and Hohhot Huyi power plant,respectively.Dissolution characteristics of Si and Al from these fly ash samples at hydrothermal synthesis circumstance were studied,and then they were used as a guide to adjust the SiO2/Al2O3 molar ratio of gel system,as a result A-zeolite and X-zeolite were synthesized directionally by hydrothermal synthesis method.X-ray diffraction （XRD） was used to identify the type of zeolite.Effect of alkalinity on the synthesis of zeolite was investigated.The results show that the amount of Si and Al dissolved from fly ash are much less than that in the chemical composition of fly ash;with the increase of dissolution time,amount of dissolved Si increases,while amount of dissolved Al rises first and drops later.Higher alkalinity is beneficial to the formation and growth of A-zeolite crystal nucleus.Besides,X-zeolite also can be synthesized directionally.It could be concluded that it is the Si and Al dissolved from fly ash at hydrothermal circumstance that are available components in the hydrothermal synthesis of zeolite,under guide of which a variety of zeolites can be synthesized directionally.