Production method of 4-A molecular sieve

Abstract

A production method of 4-A molecular sieve is disclosed, wherein raw materials comprise sodium silicate solution which is obtained through resolving intermediate product sodium silicate solution or product white carbon black in alkaline solution or sodium silicate solution with low modulus and low concentration in the manufacturing process of silicon dioxde which is extracted by adopting the coal ash alkali-soluble method, intermediate product sodium aluminate solution or product aluminum hydroxide, and aluminum oxide solution which are obtained in the production process of aluminum oxide through the coal ash desiliconisation sintering method, sodium-hydroxide and water, the components satisfy the following mole proportion conditions: SiO2: Al2O3=1.5-2.5, Na2O: SiO2=1-10, and filled water H2O: Na2O=10-80, the raw materials are mixed, are stirred into glue, and are added with guiding agent, the temperature rises to 70-100 DEG C, the mixed solution is stationarily placed for crystallization, then the soultion is led out, filtered and washed until the pH value is smaller than 11, and finally the solution is dried in 70-80 DEG C for abtaining 4-A molecular sieve.

Description

technical field [0001] The present invention relates to a kind of production method of 4A molecular sieve, especially a kind of using fly ash, through fly ash pre-desilication process and fly ash or its desiliconized ash after dissolution process obtained in the product sodium silicate etc. Aluminum source and aluminum source such as sodium aluminate are raw materials, and the method for synthetically producing 4A molecular sieve with appropriate amount of sodium hydroxide. Background technique [0002] The crystals that adsorb or repel molecules of different substances according to the size of the pores inside the crystals are called "molecular sieves". Molecular sieves produce selective adsorption according to the size and shape of molecules. Substances with molecular diameters smaller than the pore diameter of molecular sieve crystals can enter molecular sieve crystals. be attracted, otherwise be repelled. Molecular sieves only adsorb those molecules smaller than the por...

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Problems solved by technology

[0010] 1) The concentration of the reaction solution according to the metering ratio of this method is too low, wherein the SiO in the silicon source 2 The content generally does not exceed 50g / L, and the aluminum source is based on Al 2 o 3 The concentration of the raw material is not more than 45g / L. Such a low raw material concentration is basically not suitable for the hydrothermal synthesis reaction of 4A molecular sieve. Even if the reaction is carried out, the solid-liquid ratio will inevitably be high, which requires a large amount of water consumption, resulting in difficulty in filtering and washing, and energy consumption. Increase, but also reduce reaction efficiency, synthesis rate and finished product yield;

[0011] 2) In order to solve the cost and equipment problems encountered in the process of removing impurities from raw materials, this method adopts a supplementary process of re-dissolving the silicon source or aluminum source, but this process only directly dissolves silicon or aluminum in the lye, which will cause It causes waste of finished silicon and aluminum, and it is not feasible in terms of cost;

[0012] 3) The reaction time of the method is too long, which increases energy consumption, reduces production efficiency, and prolongs the production cycle;

[0013] 4) The crystallization temperature of this method is generally too high, basically around 90°C. Such a temperature is easy to produce miscellaneous crystals, which affects the quality of the product

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