Method for extracting high-purity alumina and silica gel from coal ash

A high-purity alumina and fly ash technology, which is applied in the preparation of silica, silica, alumina/hydroxide, etc., can solve the problems of large residue, complex process, low extraction rate of alumina and silica gel, etc. , to achieve the effect of low equipment requirements and high purity

Active Publication Date: 2008-09-03
安岭(陕西)环境科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The purpose of the present invention is to provide a simple process, low energy consumption, A method for extracting high-purity alumina and silica gel from fly ash with high extraction rate and purity of alumina and silica gel

Method used

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  • Method for extracting high-purity alumina and silica gel from coal ash

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Experimental program
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Effect test

Embodiment 1

[0041] (1) Grind the fly ash to make its particle diameter 200 mesh, mix the ground fly ash with Na 2 CO 3 By weight percent fly ash: mixing and stirring in the ratio of sodium carbonate=1: 2~4;

[0042] (2) Calcining the mixture formed in step (1) at a temperature of 600° C. for 1 hour;

[0043] (3) Add an appropriate amount of water to the sintered product, by weight percentage sintered product: water=1:50, the Na in the sintered product 2 SiO 3 and NaAlO 2 Dissolved in water, leached for 0.5 hours at a temperature of 60°C and then filtered;

[0044] (4) the CO obtained in step (2) is passed into the concentrated filtrate obtained in step (3). 2 , filtered after charcoal separation for 2 hours to obtain H 2 SiO 3 and Al(OH) 3 mixture;

[0045] (5) In the filter residue of step (3) and (4) gained, add industrial hydrochloric acid, its solid-liquid weight percentage is 1: 3, under the condition of 50 ℃ of extraction temperature, extraction time 20 minutes, separation ...

Embodiment 2

[0053] (1) Grind the fly ash to make the particle diameter 220 mesh, mix the ground fly ash with Na 2 CO 3 Fly ash by weight percent: sodium carbonate=1: mix and stir in the ratio of 0.5~2;

[0054] (2) Calcining the mixture formed in step (1) at a temperature of 800° C. for 2 hours;

[0055] (3) Add appropriate amount of water to the sintered product, sintered product by weight percentage: water=1:120, Na in the sintered product 2 SiO 3 and NaAlO 2 Dissolved in water, leached for 1 hour at a temperature of 80°C and then filtered;

[0056] (4) the CO obtained in step (2) is passed into the concentrated filtrate obtained in step (3). 2 , filtered after charcoal separation for 2 hours to obtain H 2 SiO 3 and Al(OH) 3 mixture;

[0057] (5) In the filter residue obtained in steps (3) and (4), add industrial hydrochloric acid, its solid-liquid weight percentage is 1: 4, under the condition of extraction temperature 75 ℃, extraction time is 40 minutes, separation system is ...

Embodiment 3

[0065] (1) Grind the fly ash to make its particle diameter 240 mesh, mix the ground fly ash with Na 2 CO 3 By weight percent fly ash: mixing and stirring in the ratio of sodium carbonate=1: 4~5;

[0066] (2) Calcining the mixture formed in step (1) at a temperature of 1000° C. for 2 hours;

[0067] (3) Add appropriate amount of water to the sintered product, sintered product by weight percentage: water=1:200, Na in the sintered product 2 SiO 3 and NaAlO 2 Dissolved in water, leaching at 95°C for 0.5 to 2 hours and then filtering;

[0068] (4) the CO obtained in step (2) is passed into the concentrated filtrate obtained in step (3). 2 , filtered after charcoal separation for 2 hours to obtain H 2 SiO 3 and Al(OH) 3 mixture;

[0069] (5) In the filter residue of step (3) and (4) gained, add industrial hydrochloric acid, its solid-liquid weight percentage is 1: 5, under the condition of extraction temperature 90 ℃, extraction time 60 minutes, separation system is an acid...

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Abstract

The invention discloses a method for extracting high-purity alumina and silica gel from the flyash. The method includes calcining and activating the powdered coal at low temperature; water extracting the alumina; acid extracting the alumina and the silica gel; separating the alumina and the silica gel; separating the alumina and the iron; recycling and reutilizing the CO2 generated during the calcining and recycling the alkali, the sodium chloride, the acid and the water during the extractions. The extracted alumina and silica gel have high purity and are used as high added value products. The separation extraction rates of the alumina and the silica gel in the fly ash reach more than 90%. The residue amount obtained after extracting the alumina and the silica gel from the fly ash is less than 10% of the fly ash. The entire technological process is carried out under the normal pressure, therefore the method has low requirement for equipment. Since the CO2 generated during the calcining and the alkali and the acid used in the extraction can be reutilized, the method can realize zero discharge without secondary pollution.

Description

technical field [0001] The invention belongs to the technical field of solid waste recovery and utilization, and in particular relates to a method for extracting high-purity alumina and silica gel from fly ash. Background technique [0002] Fly ash is the solid waste residue from coal-fired power plants. At present, the total storage of fly ash in my country has exceeded 1 billion tons, and it is still increasing at a rate of about 100 million tons per year, which not only occupies a large amount of land resources, but also seriously pollutes the environment. [0003] Coal-fired enterprises must implement the comprehensive utilization of fly ash in the near future, and realize the goal of zero discharge of waste through recycling. At present, most of fly ash at home and abroad are used to burn cement, hollow bricks, etc., which is only a low-level utilization, and it is often difficult to obtain good economic benefits. Therefore, how to improve the utilization value of fly...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/30C01B33/14
Inventor 潘爱芳杨胜科马润勇
Owner 安岭(陕西)环境科技有限公司
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