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Method for synthesis of 4A molecular sieve with coal ash alkali melting method

A technology of fly ash and molecular sieve, which is applied in related technical fields, can solve the problems of long reaction route, high production cost and high equipment requirements, and achieve the effects of improving utilization rate, good gelling performance and reducing alkali consumption

Inactive Publication Date: 2009-02-18
XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Fly ash has a large amount of emissions in my country and is widely distributed. In the existing fly ash alkali fusion synthesis 4A molecular sieve process, acid is first added to extract the alumina in the fly ash, and then the acid slag is adjusted to be neutral. A large amount of alkali is added to extract silicon oxide, and finally the existing complex route for molecular sieve synthesis is carried out by adjusting the ratio of silicon and aluminum in the product. High equipment requirements, difficult to achieve in actual production, and high production costs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Take Al 2 o 3 36% to 46%, SiO 2 / Al 2 o 3 Fly ash with a molar ratio between 1.8 and 2.1 is used as raw material, take 34g NaOH, and 20g fly ash according to NaOH 2 O / Al 2 o 3 Mix with alkali at a molar ratio of 3 to 10, remove impurities from the mixed material, and charge the finely mixed mixture in a high-temperature furnace at 600°C for 2 hours for activation. The height of the mixture in the high-temperature furnace is controlled at Each layer is 5cm, take it out and extract it with water after cooling, and control the H 2 O / Na 2 The molar ratio of O is 60, stirred at 80°C for 1.5 hours to form a gel, then raised to 95°C and left to stand at a constant temperature for 5 hours to crystallize, filtered with suction, washed to pH = 11, and dried to obtain 4A molecular sieve product. Tests have proved that the 4A molecular sieve of this embodiment has a calcium exchange capacity of 316.3mg CaCO 3 / g and the sieving rate through a 1.25mm sieve is not less than ...

Embodiment 2

[0026] In order to further examine the various parameters involved in the process, the difference between this embodiment and Example 1 is that the temperature of the high-temperature furnace is adjusted to 800°C, the calcination activation time is 1 hour, and the height of the mixture charge in the high-temperature furnace is controlled at Layer 8cm, then raise the temperature to 110°C and let stand at a constant temperature for 4 hours to crystallize, filter with suction, wash the crystals until pH = 10, and the rest are the same as in Example 1. Tests have proved that the calcium exchange capacity of the obtained 4A molecular sieve is the same as that in Example 1. .

Embodiment 3

[0028] The difference between this example and Example 1 is that the temperature of the high-temperature furnace is adjusted to 550° C., the calcination activation time is 3 hours, the height of the mixture charge in the high-temperature furnace is controlled at 4 cm per layer, and the crystallization time at constant temperature is After 6 hours, add water to dissolve the mixed material and stir for 2 hours at 55°C to form a gel, then raise the temperature to 100°C, stand at constant temperature for 6 hours to crystallize, filter with suction, wash the crystals until pH = 9, and the rest are the same as in Example 1. The obtained 4A molecular sieve has been tested and proved to have the same calcium exchange capacity as that in Example 1.

[0029] It should be noted that the present invention is not limited to the above examples, for example, after dissolving in water, controlling H 2 O / Na 2 The molar ratios of O are 30, 40 and 50 respectively, and the obtained 4A molecular ...

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Abstract

The invention discloses a method for synthesizing 4A molecular sieve by adopting the fly ash in alkaline dissolving method; the fly ash with Al2O3 being more than or equal to 36 percent (36 percent to 46 percent), and the mol ratio of the SiO2 / Al2O3 being 1.8 to 2.1 is used to be mixed with alkali according to the mol ratio of Na2O / Al2O3 is 3 to 10, and to be milled and well distributed; the mixed material with the height of each layer being 4 to 8 cm is arranged inside a high-temperature furnace at the temperature of 550 to 800 DEG C to be calcined and activated for 1 to 3 hours. After being dissolved by the water, the mol ratio of H2O / Na2O is controlled to be 30 to 60, and is mixed at the temperature of 50 to 80 DEG C for 1 to 3 hours, and is colloidized, and then is heated to the temperature of 100 plus or minus 10 DEG C to be held quietly for the crystallization for 4 to 6 hours; after the reaction, the material is filtered, and is washed until the pH value is equal to 9 to 11, and is dried to get the 4A molecular sieve. The molecular sieve is white, the calcium exchanging quantity is more than or equal to 310 mg of CaCo3 / g; and the sieving rate is more than or equal to 90 percent. The invention can integrally use the fly ash of the waste pollutant, and has the advantages of high utilization rate, simple process flow procedures, environmental protection, and the like.

Description

technical field [0001] The invention relates to molecular sieve related technology, in particular to a method for synthesizing 4A molecular sieve by using fly ash as raw material and adopting fly ash alkali fusion method. Background technique [0002] Molecular sieve is a kind of crystalline aluminosilicate, which has the properties of large specific surface area, high hydrothermal stability, rich and uniform micropores, etc. It has been widely used in chemical industry, petroleum industry and other departments, but due to the lack of natural minerals and variety Relatively monotonous, natural molecular sieves are far from meeting the requirements of the market. Therefore, sodium aluminate, sodium silicate and clay minerals are generally used as raw materials to synthesize various types of molecular sieves, which can be produced and applied on a large scale. At present, industrial production of 4A molecular sieves generally uses water glass, bentonite and kaolin as raw mater...

Claims

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Application Information

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IPC IPC(8): C01B39/14
Inventor 白光辉徐鹏陈双莉腾玮王香港
Owner XI'AN UNIVERSITY OF ARCHITECTURE AND TECHNOLOGY
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