A kind of method of synthesizing sapo-20 molecular sieve

Abstract

The invention relates to a method for synthetizing an SAPO-20 molecular sieve in a low cost. The method comprises the steps of: adding water to an inorganic base and organic amine, compounding the inorganic base, the organic amine and the water into a solution, and then, adding an SAPO-34 molecular sieve in the solution, wherein the quality ratio of the inorganic base to the organic amine, the water and the SAPO-34 molecular sieve is [5-15]:[126-175]:550:1; uniformly stirring the inorganic base, the organic amine, the water and the SAPO-34 molecular sieve at a room temperature so as to obtain a mixture, and then, performing crystallization for 3-5 days under the condition of 150-170 DEG C; cooling the crystallized mixture after crystallization, washing the cooled mixture, and drying the washed mixture so as to obtain products. According to the method disclosed by the invention, industrial raw materials or solid waste, which is low in cost, is used as raw materials, particularly the solid waste, namely the SAPO-34 molecular sieve is used as silicon sources, aluminum sources and phosphorus sources, so that not only can the synthetizing cost of the molecular sieve be reduced, but also the environmental protection is facilitated.

Description

technical field [0001] The invention belongs to the field of molecular sieve preparation, in particular to a method for synthesizing SAPO-20 molecular sieves. Background technique [0002] AlPO-20, SAPO-20 and sodalite are heterogeneous and isomorphous to each other, belonging to the cubic crystal system, and their space group is Im 3 m. Due to the difference in ionic radius and T-O bond length of the framework elements that make up the molecular sieve, the unit cell constant of AlPO-20 molecular sieve is larger than that of sodalite, but slightly smaller than that of SAPO. 4 The corresponding value of -20. The pore size of SAPO-20 molecular sieve is 0.3nm (6 member ring), the pore volume is 0.40cm 3 / g. The synthesis methods of SAPO-20 molecular sieves currently include hydrothermal crystallization, dry sol conversion and liquid phase crystallization. The raw materials for synthesizing SAPO-n molecular sieves, silicon sources mainly include: silica sol, silicic acid, s...

AI Technical Summary

Problems solved by technology

The existing method for synthesizing SAPO-20 molecular sieve uses disposable chemical raw materials, including silicon source, aluminum source and phosphorus source, and hydrothermal crystallization method and dry gel conversion method also need expensive tetramethylammonium hydroxide as template agent , the synthesis cost is relatively high

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