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Method for leaching aluminum oxide in fly ash by using microwave acid dissolution

A technology of alumina and fly ash, applied in the direction of aluminum sulfate, aluminum-sulfur compounds, etc., can solve the problems of low extraction rate of equivalent alumina, and achieve the effects of shortening reaction time, lowering reaction temperature and rapid reaction

Inactive Publication Date: 2012-08-22
JILIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The test was carried out in an open system using a household microwave oven, and the leaching rate of aluminum sulfate was only 62%, and the extraction rate of equivalent alumina would be even lower

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] (1) Get 100g fly ash and put it into a microwave digestion tank;

[0030] (2) Add 220mL of water and mix well;

[0031] (3) Add 88mL 98% concentrated sulfuric acid and mix well;

[0032] (4) Microwave heating was carried out under stirring in a closed system for 15 minutes, the microwave heating power was 500W, the reaction temperature was 140°C, and the pressure was 0.15MPa;

[0033] (5) Solid-liquid separation and washing until the filter residue is close to neutral to obtain an aluminum sulfate solution. Converting aluminum sulfate to alumina is a well-known technology and will not be repeated here.

[0034] Under this condition, the dissolution rate of alumina was 90.04%.

Embodiment 2

[0036] (1) Get 100g fly ash and put it into a microwave digestion tank;

[0037] (2) Add 455mL of water and mix well;

[0038] (3) Add 130mL 98% concentrated sulfuric acid and mix well;

[0039] (4) Microwave heating was carried out for 5 minutes under stirring in a closed system, the microwave heating power was 800W, the reaction temperature was 150°C, and the pressure was 0.22MPa;

[0040] (5) Solid-liquid separation and washing until the filter residue is close to neutral to obtain an aluminum sulfate solution. Converting aluminum sulfate to alumina is a well-known technology and will not be repeated here.

[0041] Under this condition, the alumina extraction rate was 90.85%.

Embodiment 3

[0043] (1) Get 100g fly ash and put it into a microwave digestion tank;

[0044] (2) Add 350mL water and mix well;

[0045] (3) Add 100mL 98% concentrated sulfuric acid and mix well;

[0046] (4) Microwave heating was carried out under stirring in a closed system for 10 minutes, the microwave heating power was 1000W, the reaction temperature was 170°C, and the pressure was 0.31MPa;

[0047] (5) Solid-liquid separation and washing until the filter residue is close to neutral to obtain an aluminum sulfate solution. Converting aluminum sulfate to alumina is a well-known technology and will not be repeated here.

[0048] Under this condition, the extraction rate of alumina was 91.43%.

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Abstract

The invention relates to a method for leaching aluminum oxide in fly ash by using microwave acid dissolution, which comprises the following steps of: grinding fly ash to be less than 200 meshes and putting the fly ash into a microwave reactor; adding water and uniformly mixing the water with the fly ash in a certain liquid state; adding 98 percent of concentrated sulfuric acid into the mixture according to a consumption acid theoretical value of aluminum oxide and other cation oxide in the fly ash and uniformly mixing; stirring the mixture in an airtight system to perform microwave heating reaction; and performing solid-liquid separation, washing and residue-filtering until the mixture is approach to be neutral to obtain an aluminum sulfate solution. The aluminum oxide in the fly ash is leached by using sulfuric acid as a leaching agent and using microwave as a heating source, the traditional heating method is changed, and the high frequency property and the penetrability of microwave heating are fully utilized, so that the interior of a system of the fly ash and the sulfuric acid is uniformly heated, and the reaction between the sulfuric acid and the sulfuric acid particle is speeded up, so that the dissolution speed of the aluminum oxide in the fly ash is speeded up, the reaction time is greatly shortened, and the dissolution rate of the aluminum oxide is improved to ensure that the dissolution rate of the aluminum oxide is more than 90 percent. By adopting the microwave acid dissolution method, the energy consumption can be reduced, and energy sources can be saved.

Description

technical field [0001] The invention relates to a resource utilization method of coal solid waste, in particular to a method for acid-dissolving and leaching alumina from fly ash. Background technique [0002] my country is the country with the largest thermal power generation in the world, and it is also the country with the largest emission of fly ash. In recent years, my country's electric power industry has developed rapidly, and the total amount of thermal power generation has also increased rapidly. Therefore, the emission of fly ash is also increasing year by year. At present, the cumulative stockpiles of fly ash in my country have reached nearly 2 billion tons. The comprehensive utilization of fly ash in my country has been highly valued by the state for a long time, especially the high value-added utilization of fly ash has attracted more and more attention from relevant scholars. Many researchers have carried out studies on fly ash, especially high-alumina fly a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/74
Inventor 魏存弟张培萍蒋引珊李楠高钱薛兵徐少南孙彦斌李芳菲杨殿范
Owner JILIN UNIV