Method for producing superfine aluminium hydroxide and aluminium oxide by using flyash

A technology of ultra-fine aluminum hydroxide and fly ash, applied in alumina/aluminum hydroxide, products, reagents, etc., can solve the problems of complicated production process, increase production cost, etc., achieve high selectivity, reduce emissions, The effect of reducing silicon content

Inactive Publication Date: 2010-10-27
CHINA SHENHUA ENERGY CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method of acid-dissolving first and then alkali-dissolving complicates the production process and increases the production cost

Method used

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  • Method for producing superfine aluminium hydroxide and aluminium oxide by using flyash
  • Method for producing superfine aluminium hydroxide and aluminium oxide by using flyash
  • Method for producing superfine aluminium hydroxide and aluminium oxide by using flyash

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] (1) Get circulating fluidized bed fly ash, pulverize to 200 orders, use embodiment 12 to be used for the vertical ring magnetic separator of fly ash iron removal to carry out wet magnetic separation and make the iron oxide content in the ash down to 0.8wt %. The filter cake after the magnetic separation is put into an acid-resistant reaction kettle, and the industrial hydrochloric acid with a concentration of 37wt% is added to carry out acid-dissolving reaction. The molar ratio of HCl in hydrochloric acid to alumina in fly ash is 4.5:1, and the reaction temperature is 200°C. Pressure 2.1MPa, reaction time 1 hour. After the reaction product was filtered and washed by a plate basket filter press, a hydrochloric acid immersion solution with a pH value of 1.7 was obtained. It was determined that the extraction rate of alumina in the fly ash was 84.2%.

[0047] (2) After cooling the hydrochloric acid immersion solution to 65°C through heat exchange, use a corrosion-resistan...

Embodiment 2

[0053] Except step (1), other operating process conditions are all identical with embodiment 1. The operating process condition adjustment in the step (1) is:

[0054] (1) Get circulating fluidized bed fly ash, pulverize to 150 orders, use embodiment 12 to be used for the vertical ring magnetic separator of fly ash to remove iron to carry out wet magnetic separation and make the iron oxide content in the ash drop to 0.8wt %. The filter cake after the magnetic separation is put into an acid-resistant reaction kettle, and the industrial hydrochloric acid with a concentration of 28wt% is added to carry out acid-dissolution reaction. The molar ratio of HCl in the hydrochloric acid and alumina in the fly ash is 5: 1, and the reaction temperature is 150°C. Pressure 1.0MPa, reaction time 2 hours. The reaction product was filtered and washed by a plate basket filter press to obtain a hydrochloric acid immersion solution with a pH value of 1.5. It was determined that the extraction r...

Embodiment 3

[0057] Except step (1), other operating process conditions are all identical with embodiment 1. The operating process condition adjustment in the step (1) is:

[0058] (1) Get circulating fluidized bed fly ash, pulverize to 200 orders, use embodiment 12 to be used for the vertical ring magnetic separator of fly ash iron removal to carry out wet magnetic separation and make the iron oxide content in the ash down to 0.8wt %. The filter cake after the magnetic separation is put into an acid-resistant reaction kettle, and the industrial hydrochloric acid with a concentration of 20wt% is added to carry out the acid-dissolving reaction. The pressure is 0.1MPa, and the reaction time is 4 hours. After the reaction product was filtered and washed by a basket filter press, a hydrochloric acid immersion solution with a pH value of 1.4 was obtained, and the extraction rate of alumina in the fly ash was determined to be 80.1%.

[0059] After determination, the chemical composition and p...

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Abstract

The invention discloses a method for producing superfine aluminium hydroxide and aluminium oxide by taking flyash of a recirculating fluidized bed as a raw material. The method comprises the following steps of: a) grinding the flyash, performing wet magnetic separation and deironization, and reacting with hydrochloric acid to obtain hydrochloric acid extract; b) introducing the hydrochloric acid extract into a macroporous cationic resin column for adsorption, after adsorptive saturation of the resin, eluting by using an eluant to obtain eluent containing aluminium chloride and iron chloride; c) removing iron from the eluent by using alkaline solution to obtain solution of sodium metaaluminate; d) adding a dispersing agent into the solution of sodium metaaluminate, and mixing uniformly to obtain dispersion; and e) performing carbon decomposition on the dispersion to obtain the superfine aluminium hydroxide. The superfine aluminium hydroxide is calcined at different temperatures to form gamma-aluminium oxide and alpha-aluminium oxide respectively. Compared with other methods, the method has the advantages of wide sources of raw materials, simple production process and high purity of the products.

Description

technical field [0001] The invention relates to a method for preparing superfine aluminum hydroxide and alumina from fly ash, and is especially suitable for the method for producing superfine aluminum hydroxide and alumina from circulating fluidized bed fly ash. Background technique [0002] Ultrafine aluminum hydroxide generally refers to ultrafine aluminum hydroxide with uniform particles and an average particle size of less than 1 μm. It is widely used in chemistry, medicine, catalysts and their carriers, rubber, pigments, papermaking, refractory materials, and insulating materials. , Ceramics and other fields play an extremely important role in the national economy. Due to its excellent physical and chemical properties, ultra-fine alumina is also widely used in various technical fields such as machinery, metallurgy, petroleum, chemical industry, electronics, optics, nuclear reaction, and aerospace. [0003] The production of ultra-fine aluminum hydroxide and alumina can...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02
CPCY02P20/141
Inventor 李楠魏存弟孙延彬张培萍池君洲董宏
Owner CHINA SHENHUA ENERGY CO LTD
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