Synthesis Of Zeolite From Rice Husk Silica

China is the largest rice-growing country in the world. Rice husk is the main by-product of rice, accounting for about20%of husk mass fraction. The annual output of rice husk in our country is about4million t, the number is very large. However, because of the low nutritional value, high silica content, high hardness, be difficult for soil to digest and the low density, it is generally regarded as agricultural waste, which is not only causing environmental pollution but also making resource waste. Zeolite has special cave structure, good adsorption and catalytic properties. Currently, in the field of petrochemical and household chemicals it has a wide range of application. So this paper uses of the rice husk silicon for the synthesis of molecular sieve, and this method has practical significance.There are two ways that synthesis of zeolite P by a hydrothermal method using rice husk ash as silicon source are studied in this paper:synthesis of zeolite P from rice husk ash^synthesis of zeolite P by the method of adding crystal and synthesis of zeolite by calcining the rice husk once. Using of single factor test to detect the impact of every factor in the synthesis process, so as to determine the optimal synthesis technology. The results show that:(l).The optimal synthesis technology to synthesis of zeolite P from rice husk ash is that n(Na2O)/n(SiO2)=1.2, n(SiO2)/n(Al2O3)=7.0, n(H2O)/n(Na2O)=25, at the crystallization temperature of85℃and reaction time of10h, giving maximum calcium exchange ability of that305.4mg of calcium carbonate can be absorbed by per gram of zeolite P. The main advantage of this method without the need for crystallization and the aging process, compared with the conventional hydrothermal method, shortening the synthetic route.(2).The optimal synthesis technology to synthesis of zeolite by calcining the rice husk once is that calcination temperature of850℃, calcination time of8h, n(Na2O)/n(SiO2)=1.2, n(SiO2)/n(Al2O3)=4.0, n(H2O)/n(Na2O)=35, fine crystallinity at the crystallization temperature of90℃and reaction time of10h, give maximum calcium ionic exchange ability of that300.72mg of calcium carbonate can be absorbed by per gram of zeolite P. Because of the calcination, it makes the reactants play a good activation and omits the way to get silica from rice hust first and then to synthesis of zeolite. The structure of the products obtained throgh two ways of structural inspection methods, XRD and SEM. From the results we may find that the products have typical characteristic peak of zeolite P and the narrower grain-size distribution, with impurity-free and regular crystal.The P-type zeolite prepared calcium exchange ability has reached the standard of departments, it can be effective for water softening and used as a cleaning agent. Using agricultural wasted rice husk as the silicon source to synthesize P-type zeolite is characterized by a significant low-cost raw materials, the synthestic method is simple and easy to spread; it is not only solving the pollution of the environment that caused by wasted rice husk, but also greatly enhancing the application value of rice husk and expanding a new way to effective using of agricultural waste.