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Method for preparing alumina from fly ash

A technology for alumina and fly ash is applied in the field of preparing alumina by using fly ash, which can solve the problems of secondary pollution, high cost and high energy consumption, and achieve the effects of being beneficial to industrialization, utilization and easy utilization.

Inactive Publication Date: 2012-02-08
SHENYANG ALUMINIUM MAGNESIUM INSTITUTE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are still some problems in the extraction of alumina from fly ash by alkaline method, mainly ① the calcium-silicate slag produced by sintering method can only be used as cement raw material, and the production of 1 ton of alumina will produce several times the silicon content of fly ash Calcium slag, while cement has its corresponding sales radius, if there is no large-scale cement industry support in the local area, it will cause secondary pollution; ②The sintering method only extracts the alumina in the fly ash, and the use value of its silica is low
③ The sintering method for processing fly ash equipment requires large investment, high energy consumption and high cost

Method used

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  • Method for preparing alumina from fly ash
  • Method for preparing alumina from fly ash

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Raw fly ash is mainly composed of the following components: Al 2 o 3 : 41%, SiO 2 : 48%, Fe 2 o 3 : 3.3%, CaO: 3.3%, TiO 2 : 1.3%, MgO: 0.2%. The composition of the raw fly ash can also use other components, which cannot be used to limit the protection scope of the present invention.

[0020] Mix fly ash and ammonium sulfate solution and wet grind to obtain raw meal, wherein the weight ratio of ammonium sulfate and alumina in fly ash is 5:1; heat the raw meal to 450°C and keep it warm for 1 hour to make clinker. The discharged ammonia gas is used for the decomposition of aluminum ammonium sulfate; the clinker is dissolved in hot water with a mill for 0.5h, aluminum enters the solution in the form of aluminum ammonium sulfate, and silicon remains in the solid to form high-silicon slag; after dissolution, the slurry passes through the settling tank Separation and three-stage countercurrent washing, the liquid is aluminum ammonium sulfate solution, and the solid slag...

Embodiment 2

[0022] The raw material fly ash and ammonium sulfate crystals in Example 1 were mixed and dry-milled to obtain a raw meal, wherein the weight ratio of ammonium sulfate to alumina in the fly ash was 4.5:1; the raw meal was heated to 230°C and kept at 0.5 h, making clinker, the discharged ammonia gas is used for the decomposition of aluminum ammonium sulfate; the clinker is dissolved in hot water for 0.1h with stirring, aluminum enters the solution in the form of aluminum ammonium sulfate, and silicon remains in the solid to form high-silicon slag; After dissolution, the slurry is separated by a filter and washed in two countercurrents. The liquid is aluminum ammonium sulfate solution, and the solid slag is high-silicon slag; ammonia water is passed into the aluminum ammonium sulfate solution, and ammonia water is made by adding water to ammonia gas produced by clinker firing. , so that the solution is decomposed into aluminum hydroxide solid, and the liquid is ammonium sulfate s...

Embodiment 3

[0024] The raw material fly ash in Example 1 is mixed and dry-milled with ammonium sulfate crystals to obtain a raw meal, wherein the weight ratio of ammonium sulfate and alumina in the fly ash is 7:1; the raw meal is heated to 300° C. and kept for 3 hours , to make clinker, and the discharged ammonia gas is used for the decomposition of aluminum ammonium sulfate; the clinker is dissolved in hot water for 1.3h with stirring, aluminum enters the solution in the form of aluminum ammonium sulfate, and silicon remains in the solid to form high-silicon slag; After the slurry is separated by a filter and washed in the first stage of countercurrent, the liquid is ammonium aluminum sulfate solution, and the solid slag is high-silicon slag; ammonia water is passed into the ammonium aluminum sulfate solution, and ammonia water is made by adding water to ammonia gas produced by clinker burning. The solution is decomposed into solid aluminum hydroxide, and the liquid is ammonium sulfate so...

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Abstract

The invention discloses a method for preparing alumina through industrial solid waste treatment and utilization, and specially, relates to a method for preparing alumina from fly ash. The method for preparing alumina from fly ash comprises the following steps of grinding raw materials, calcining the grinded raw materials into clinker, carrying out separation and washing to obtain high-silicon content slag, decomposing an ammonium aluminum sulfate solution, separating and washing aluminum hydroxide obtained by the previous step, carrying out calcination of aluminium hydroxide obtained by the previous step to obtain alumina as a product, evaporating an ammonium sulfate solution and the like. The method for preparing alumina from fly ash does not adopt any auxiliary agent. Through the method for preparing alumina from fly ash, alumina can be extracted effectively from fly ash, wherein an extraction rate of alumina reaches above 90%.

Description

technical field [0001] The invention relates to a method for producing alumina by treating and utilizing industrial solid waste, in particular to a method for preparing alumina by using fly ash. Background technique [0002] Fly ash is a solid waste from coal-fired power plants. In 2008, the annual discharge of fly ash in my country was as high as 300 million tons, and the total stockpile of fly ash in my country was more than five to six billion tons. The discharge of a large amount of fly ash not only occupies a large amount of land, but also seriously pollutes the environment, which constitutes a double damage to the ecology and the environment. Therefore, the comprehensive utilization of fly ash has great practical and long-term strategic significance. Similarly, my country is a country that is not rich in aluminum resources. According to the current growth rate of alumina production and bauxite mining, even considering the future reserves, it is difficult for my count...

Claims

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Application Information

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IPC IPC(8): C01F7/02B09B3/00
Inventor 李来时刘瑛瑛周凤禄廖新勤
Owner SHENYANG ALUMINIUM MAGNESIUM INSTITUTE
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