Organic-template-free [beta]-molecular sieve synthesizing method

Abstract

The invention relates to an organic-template-free [beta]-molecular sieve synthesizing method which includes following steps: mixing a silicon dioxide source, an aluminum oxide source, a sodium oxide source and water, wherein molar ratios of the raw materials are described as follows: SiO2 / Al2O3=5-25, Na2O / SiO2=0.18-0.5 and H2O / SiO2=1-7.6, stirring the raw materials to generate initial gel and continuously stirring the gel until the gel is turned into dry gel, adding a [beta]-molecular sieve seed crystal, and performing hydrothermal crystallization at 100-180 DEG C for 12-130 h to obtain the [beta]-molecular sieve, wherein the ratio of SiO2 to Al2O3 in the [beta]-molecular sieve seed crystal is 11-70 and the addition amount of the [beta]-molecular sieve seed crystal is 0.5-5% by mass of the silicon dioxide source. By means of the method, the high-quality [beta]-molecular sieve crystal can be directly synthesized. Because that the addition amount of the seed crystal is less and the synthetic temperature is low, the synthesizing method is effectively reduced in cost. Because that none organic template free is added, the [beta]-molecular sieve has unobstructed pore channels without roasting, thereby further reducing the energy consumption during the production process. Because that the added water is quite less in amount, the synthesizing method is increased in utilization rate of the silicon source and is greatly increased in yield of single kettle.

Description

technical field [0001] The invention belongs to the fields of inorganic chemistry, physical chemistry, material chemistry, catalytic chemistry and chemical engineering, and particularly relates to a method for synthesizing beta zeolite molecular sieve without organic template. Background technique [0002] Traditional β molecular sieves are prepared in the presence of organic templates such as TEA+, and there are very obvious shortcomings: first, the price of organic templates is very high, resulting in high cost of molecular sieves, which affects their wide application; secondly, in the removal of molecular sieves The method of high-temperature burning is usually used for organic templates, which will lead to a significant decrease in the crystallinity of molecular sieves and produce a large amount of harmful gases to pollute the environment. [0003] CN200810050456.3 discloses a "method for synthesizing β molecular sieve without organic template". The raw material molar r...

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Problems solved by technology

[0002] Traditional β molecular sieves are prepared in the presence of organic templates such as TEA+, and there are very obvious shortcomings: first, the price of organic templates is very high, resulting in high cost of molecular sieves, which affects their wide application; secondly, in the removal of molecular sieves The method of high-temperature burning is usually used for organic templates, which will lead to a significant decrease in the crystallinity of molecular sieves and produce a large amount of harmful gases to pollute the environment

Although this method avoids the use of organic templates and reduces production costs, it inevitably has the disadvantages of synthesizing molecular sieves without organic templates, such as easy generation of miscellaneous crystals, low utilization rate of raw materials, etc., especially the silicon source utilization rate of this method Relatively low (15-27%), the seed crystals cannot be reused, and the amount of water used is high, resulting in a very low single-pot yield and restricting production efficiency

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