Method for synthesizing 4A molecular sieve by double crystallization

Abstract

The invention discloses a method for synthesizing a 4A molecular sieve by double crystallization. The method comprises the following steps: pre-treating a raw material, sufficiently mixing the raw material with a NaOH solution, and performing stirring at constant speed; performing filtering and separating under a vacuum state to obtain supernate; mixing and stirring Al powder and the NaOH solutionuntil the Al powder is completely dissolved to obtain a mixed solution; mixing the mixed solution with the supernate, performing standing at constant temperature, and performing filtering to obtain aclear solution; and aging the clear solution under a room temperature condition, performing microwave assisted hydrothermal double crystallization to obtain the 4A molecular sieve. According to the method, the yield and synthesizing efficiency can be greatly improved, cost can be reduced, and industrial synthesizing application of the 4A molecular sieve can be benefited.

Description

technical field [0001] The invention belongs to the technical field of high-value utilization of industrial waste, and in particular relates to a method for synthesizing 4A molecular sieves by twin crystallization. Background technique [0002] Coal gangue is the waste ore extracted in the process of coal mining, and a large amount of it has not been used at present. The discharge and accumulation of these coal gangue not only takes up a large amount of cultivated land, pollutes the environment, but also causes harm to crops and human beings, and has become a problem that the coal industry needs to solve urgently. Biomass ash is the ash left after the biomass briquette fuel is fully burned, and a large amount of biomass ash will pollute the environment. 4A molecular sieve is a kind of synthetic molecular sieve, which is widely used in petroleum, chemical industry, metallurgy, electronic technology, medical and health departments in my country. [0003] The synthesis of 4A ...

AI Technical Summary

Problems solved by technology

[0003] The synthesis of 4A molecular sieve traditionally adopts the hydrothermal synthesis method, but the synthesis time is long, the steps are complicated, and the yield is not high, which limits its development.

The molecular sieve synthesized by the alkali fusion method does not contain the crystal phase of mullite and quartz, and improves the yield of zeolite. By adjusting the ratio of silicon to aluminum, a product with high practical value and purity can be obtained, but its disadvantages are longer activation time

The gradual heating method greatly shortens the crystallization reaction time, but the conversion rate of this method is low

The advantage of the microwave synthesis method is that it can increase the crystallization speed of the synthetic gangue zeolite, shorten the crystallization time, and reduce the synthesis cost, which provides the possibility for the industrialization of the coal gangue synthetic molecular sieve. The crystallization reaction is too violent, and the flaky precipitate dissolves, resulting in low yield

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