Method for preparing NaA molecular sieve from geopolymer

A geopolymer, molecular sieve technology, applied in the direction of A-type crystalline aluminosilicate zeolite, crystalline aluminosilicate zeolite, etc., can solve problems such as difficulty in molding NaA molecular sieve products according to application requirements, product granularity, etc. A wide range of raw materials and the effect of broadening the scope of application

Active Publication Date: 2012-07-18
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its disadvantage is that the product is granular, and it is difficult to form NaA

Method used

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  • Method for preparing NaA molecular sieve from geopolymer
  • Method for preparing NaA molecular sieve from geopolymer
  • Method for preparing NaA molecular sieve from geopolymer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] 1.Al 2 o 3 -2SiO2 2 Powder preparation:

[0032] Aluminum chloride (AR) and absolute ethanol were mixed with a molar ratio of 1:4 and magnetically stirred for 12 hours to prepare aluminum sol for use. Stir for half an hour to prepare a silica sol for use. Add aluminum sol dropwise to the stirring silica sol to prepare a composite sol with a silicon-aluminum ratio of 1:1, continue stirring for 2 hours, put it in a constant temperature water bath at 70°C until a transparent and uniform gel appears, and age at room temperature for 36 hours , dried at 105°C for 12 hours, ground, and calcined at 800°C for 2 hours to obtain amorphous Al 2 o 3 -2SiO2 2 powder ready for use;

[0033] 2. Preparation of 10 mol / L NaOH solution:

[0034] Weigh 104.17g of solid NaOH (AR) with a mass fraction of 96%, put it into a plastic beaker, add 150ml of deionized water and stir until it is completely dissolved, transfer it to a 250ml volumetric flask after cooling, add deionized water...

Embodiment 2

[0037] 1.Al 2 o 3 -SiO 2 Powder preparation:

[0038] Aluminum nitrate (AR) and absolute ethanol were mixed with a molar ratio of 1:4 and magnetically stirred for 12 hours to prepare aluminum sol for use. Silica sol was prepared in half an hour for use. Add aluminum sol dropwise to the stirring silica sol to prepare a composite sol with a silicon-aluminum ratio of 1:2, continue stirring for 2 hours, put it in a constant temperature water bath at 70°C until a transparent and uniform gel appears, and age at room temperature for 36 hours , dried at 105°C for 12 hours, ground, and calcined at 800°C for 2 hours to obtain amorphous Al 2 o 3 -SiO 2 powder ready for use;

[0039] 2. Mole ratio SiO 2 / Al 2 o 3 =2, Na 2 O / Al 2 o 3 =1, weigh 45gAl 2 o 3 -SiO 2 The powder was mixed with 66.45g of water glass and stirred for 30 minutes. The solid content of the water glass used was 37.39%, and the modulus of the water glass was 0.9. Inject into a sheet mold, maintain at 6...

Embodiment 3

[0041] 1. Preparation of metakaolin:

[0042] The kaolin powder produced by Guangxi Beihai Yankuang Group with a fineness of more than 250 meshes and washed with water was calcined in the air at 800°C for 2 hours to obtain metakaolin. Al in metakaolin 2 o 3 :42.35%, SiO 2 : 56.91%, Fe 2 o 3 :0.74%;

[0043] 2. Preparation of boehmite:

[0044] AlCl 3 ·6H 2 O(AR) was prepared into a 5mol / L solution, and the aluminum chloride solution was stirred and hydrolyzed in a water bath at 70°C for 2 hours for later use. The analytically pure ammonia water and deionized water were prepared into an ammonia solution at a mass ratio of 1:1, and the Add 100 ml of the above-prepared aluminum chloride solution dropwise into 100 ml of the prepared ammonia solution, stir while dripping, control the pH of the system to 9-10, and obtain a precipitated product. The precipitate was aged for 24 hours, washed with water, and suction filtered to fully remove Cl- and NH4+ to obtain a filter cake,...

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Abstract

The invention mainly discloses a method for preparing a NaA molecular sieve from a geopolymer. The method comprises the following steps: with metakaolin or chemically-synthesized aluminum silicate active powder as a solid raw material and sodium potassium silicate or sodium hydroxide solution as an exciting agent, adjusting the ratio of silicon to aluminum in a system by using boehmite; mixing the solid raw material with the alkali exciting agent according to the ratio of silicon to aluminum and the ratio of sodium to aluminum in the raw materials in the composition design of the NaA molecular sieve; stirring the solid raw material and the alkali exciting agent and injecting the mixture into a die; carrying out sealed curing the mixture in a thermostat at the temperature of 60-80 DEG C for 6-24 hours; feeding the cured geopolymer sample into a hydrothermal reactor; and carrying out hydrothermal crystallization on the cured geopolymer sample at the crystallization temperature of 70-110 DEG C for 4-10 hours to obtain the NaA molecular sieve. According to the method disclosed by the invention, due to the utilization of the characteristic that the geopolymer is easily formed, a NaA molecular sieve blocky material can be prepared in situ at one time. Compared with the preparation method for the NaA molecular sieve, the prepared method disclosed by the invention has the advantages of simplicity in operation, low cost and suitability for scale preparation.

Description

technical field [0001] The invention belongs to the fields of geopolymer materials and NaA molecular sieve materials, in particular to a method for preparing NaA molecular sieves from geopolymers. Background technique [0002] Geopolymer materials were proposed by French materials scientist Joseph Davidovits in 1978. It is an amorphous three-dimensional network structure formed by silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron through bridging oxygen, and alkali metal or alkaline earth metal cations play a role in balancing the negative charge of aluminum-oxygen tetrahedron. speculated that the geopolymer material is an intermediate state of zeolite molecular sieves. Usually, geopolymer materials are amorphous and non-crystalline structures, but through high-resolution transmission electron microscopy (HRTEM) analysis, our research group found that there are a small amount of nanoscale ordered structures in geopolymer materials; through further research, the geo...

Claims

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Application Information

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IPC IPC(8): C01B39/14C01B39/18
Inventor 崔学民贺艳冒进刘乐平刘兴东
Owner GUANGXI UNIV
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