Method for synthesizing 4A molecular sieve drier using kaoline

A kaolin and desiccant technology, applied in separation methods, chemical instruments and methods, dispersed particle separation, etc., can solve the problem of less research on desiccants, and achieve static water adsorption rate, high crush resistance, and good dispersibility. , the effect of high crystallinity

Inactive Publication Date: 2009-04-15
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there are many reports on 4A molecular sieve as a detergent builder, that is, there are more studies on its calcium ion exchange capacity, but less research on its use as a desiccant

Method used

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  • Method for synthesizing 4A molecular sieve drier using kaoline
  • Method for synthesizing 4A molecular sieve drier using kaoline
  • Method for synthesizing 4A molecular sieve drier using kaoline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] The kaolin raw material (SiO 2 / Al 2 o 3 The molar ratio is 2.10) into the 3.2mol / L NaOH solution (Na 2 O / SiO 2 The molar ratio is 1.5), gelation at 60°C for 3 hours, crystallization at 95°C for 4 hours, deionized water for suction filtration and washing, the pH of the filtrate is controlled at about 10.0, and the obtained product is dried at 120°C to obtain 4A molecular sieve powder. Clay mineral bentonite, which accounts for 25% by weight of the molecular sieve, is mixed and granulated. The desiccant granules are dried at room temperature and calcined at 550°C to obtain the finished desiccant product KZ-1. The specific experimental procedure is as figure 1 As shown, the synthetic 4A zeolite molecular sieve XRD pattern is as follows figure 2 As shown, the scanning electron microscope with different magnifications such as image 3 Table 1 shows the static water adsorption rate (wt%) and compressive strength (N / particle) of the desiccant.

Embodiment 2

[0039] The kaolin raw material (SiO 2 / Al 2 o 3 The molar ratio is 2.30, and the amount of alkali is used to control Na 2 O / SiO 2The molar ratio is 1.5) After grinding, add it to 150ml deionized water, gelatinize at 60°C for 2h, crystallize at 95°C for 3h, filter and wash with deionized water, control the pH value of the filtrate at about 10.0, and bake the product at 120°C Dry to get 4A molecular sieve powder. Clay mineral bentonite, which accounts for 25% by weight of the molecular sieve, is mixed and granulated. The desiccant granules are dried at room temperature and calcined at 700°C to obtain the finished desiccant product KZ-33. XRD pattern of synthetic 4A zeolite molecular sieve Figure 4 As shown, the scanning electron microscope with different magnifications such as Figure 5 Table 1 shows the static water adsorption rate (wt%) and compressive strength (N / particle) of the desiccant.

Embodiment 3

[0041] The kaolin raw material (SiO 2 / Al 2 o 3 The molar ratio is 2.22, and the amount of alkali used is Na 2 O / SiO 2 The molar ratio is 1.5) After grinding, add it to 150ml deionized water, gelatinize at 60°C for 2h, crystallize at 95°C for 3h, filter and wash with deionized water, control the pH value of the filtrate at about 13.0, and bake the product at 80°C Dry to get 4A molecular sieve powder. Clay mineral bentonite, which accounts for 25% by weight of the molecular sieve, is mixed and granulated. The desiccant granules are dried at room temperature and calcined at 700°C to obtain the finished desiccant product KZ-35. Table 1 shows the static water adsorption rate (wt%) and compressive strength (N / particle) of the desiccant.

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Abstract

The invention discloses a method for preparing a 4A zeolite molecular sieve desiccant with high crystallinity through a raw material of common natural kaolin. The method comprises the following steps: taking kaolin as the raw material, roasting the kaolin by a direct roasting method or a dry-process alkali roasting method, colloidizing, crystallizing, and suction filtrating and cleaning the kaolin through deionized water, and then drying the kaolin; and adding clay mineral bentonite or kaolin crude ore into the kaolin for granulation, and then obtaining the 4A zeolite molecular sieve desiccant after roasting. The method has the advantages that the method has a simple preparation process, raw material available, and loose operating conditions; and the synthesized 4A zeolite molecular sieve has the characteristics of high crystallinity, small particle size, good dispersibility, and high static water adsorption rate and high strength against crushing. The static water adsorption rate of the desiccant reaches 21.5 weight percent, and the strength against crushing reaches 62.1N/particle. The indexes reach the standards of the Department of Chemical Industry.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, and relates to a method for preparing a 4A type molecular sieve desiccant by using kaolin. Background technique [0002] 4A molecular sieve is an artificial zeolite molecular sieve synthesized by humans, and its chemical composition is: Na 2 O·Al 2 o 3 2SiO2 2 4.5H 2 O. The size of holes and pores of 4A molecular sieve is uniform, and its effective pore size is 0.4nm. Substances smaller than this size can be adsorbed, while substances larger than this size are excluded from adsorption, so it has the characteristic of selective adsorption. The adsorption or repulsion function of molecular sieves is affected by the electrical properties of the molecules. Synthetic zeolite has the special function of selective adsorption according to the size and polarity of molecules, so it can dry or purify gas or liquid, which is also the basis for molecular sieve separation. [0003] At pre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J20/18B01J20/30C01B39/14B01D53/28
Inventor 杨华明杜春芳
Owner CENT SOUTH UNIV
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