Method for preparing 3A type zeolite molecular sieve

Abstract

Belonging to the field of molecular sieve synthesis, the invention relates to a method for preparing a 3A type zeolite molecular sieve. The preparation method of a 3A type zeolite molecular sieve is characterized by comprising the steps of: 1) calcination of kaolin, thus obtaining metakaolin; 2) preparation of a 4A molecular sieve: mixing metakaolin and a NaOH aqueous solution uniformly, thus obtaining a mixture; filtering the mixture, washing the filter cake with distilled water, and conducting filtration again, drying the filter cake from second filtration at a temperature of 90-100DEG C for 2-4h, thus obtaining the 4A molecular sieve; 3) preparation of a 3A type zeolite molecular sieve: reacting the 4A molecular sieve with a KCl solution in a reaction vessel for 3-5h at a temperature of 70-90DEG C, then conducting cooling, washing, and filtering, drying the obtained filter cake at a temperature of 90-100DEG C for 2-4h, thus obtaining the 3A type zeolite molecular sieve. The method of the invention has simple process and low calcination temperature, and the prepared 3A type zeolite molecular sieve has great calcium ion exchange capacity and good performances.

Description

technical field [0001] The invention relates to a method for preparing 3A type zeolite molecular sieve, which belongs to the field of molecular sieve synthesis. Background technique [0002] Molecular sieve is a crystalline aluminosilicate with a uniform pore structure, and its spatial network structure is composed of silicon-oxygen tetrahedral units [SiO 4 ] and alumina tetrahedral units [AlO 4 ] are arranged in a staggered manner. The molecular sieve structure contains a large amount of crystal water. During the heating process, due to the loss of crystal water, many cavities of different sizes are formed, and many micropores with the same diameter are connected between the cavities, forming a uniform diameter of molecular size. tunnel. Therefore, molecules with a diameter larger than the pores can be excluded, thereby realizing the function of sieving molecules, and molecular sieves get their name from this. This structural feature makes molecular sieves have three ma...

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Problems solved by technology

[0018] The above Chinese patents respectively propose different methods to prepare A-type molecular sieves with kaolin as raw material, but there are still some problems: (1) the calcination temperature for preparing metakaolin is relatively high (700-1000° C. is generally required); (2) calcined kaolin and crystal Whitening agent needs to be added in the chemicalization process; the silicon-aluminum ratio needs to be adjusted; (4) The production cycle is long

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