Method for extracting aluminium oxide from pulverized fuel ash

A technology of fly ash and alumina, applied in the direction of alumina/hydroxide preparation, etc., can solve the problems of limited production scale, high equipment investment, long process flow, etc., and achieve a small amount of residue, simple method, and convenient reaction Effect

Active Publication Date: 2012-03-21
北京世纪地和控股有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Alkali method includes limestone sintering method and soda lime sintering method. At present, there are many researches on the treatment of fly ash by alkali method. The main disadvantages of alkali method for extracting alumina from fly ash are long process flow, large amount of materials and high equipment investment

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  • Method for extracting aluminium oxide from pulverized fuel ash
  • Method for extracting aluminium oxide from pulverized fuel ash

Examples

Experimental program
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Effect test

Embodiment 1

[0052] Grind fly ash containing 46% alumina and 40% silica to 325 meshes, and at the same time, sinter ammonium sulfate with a mass of 1350g at 280°C for 3 hours to prepare liquid ammonium bisulfate, and The obtained ammonia gas is recovered with water to prepare ammonia water.

[0053] According to the mass ratio of ammonium bisulfate / alumina in fly ash is 6.0, weigh the pulverized fly ash and ammonium bisulfate for sintering. The sintering temperature is 450°C, and the sintering time is 3.5 hours. It was dissolved at 98°C under normal pressure, and the dissolution rate of aluminum oxide in the ammonium aluminum sulfate solution obtained was 90%. The obtained aluminum ammonium sulfate crystals are dissolved and prepared into a 0.2mol / L aluminum ammonium sulfate solution, and then ammonia gas is introduced to decompose it, and the NH 3 The molar ratio to ammonium aluminum sulfate is 3.1, the reaction temperature is 35°C, and after 3 hours of reaction, an aluminum hydroxide so...

Embodiment 2

[0055] Grind fly ash containing 42% alumina and 40% silica to 200 meshes, and at the same time sinter ammonium sulfate with a mass of 2300g at 300°C for 2.5 hours to prepare liquid ammonium bisulfate. And recover the obtained ammonia gas with water to prepare ammonia water.

[0056] According to the mass ratio of ammonium bisulfate / alumina in fly ash is 6.5, weigh ammonium bisulfate and fly ash for sintering. The sintering temperature is 440°C and the sintering time is 2.5 hours. Dissolution at 98°C, the dissolution rate of aluminum oxide in the ammonium aluminum sulfate solution obtained was 89%. After removing impurities such as iron from the ammonium sulfate solution, the ammonium aluminum sulfate solution was cooled to 10°C to crystallize for 5 hours, and then the obtained ammonium aluminum sulfate The crystals were dissolved and prepared into 0.25mol / L aluminum ammonium sulfate solution, and then reacted with ammonia water with a concentration of 25%, NH 3 The molar rati...

Embodiment 3

[0058] Grind fly ash containing 40% alumina and 43% silica to 200 meshes, and at the same time, sinter 2000g of ammonium sulfate at 280°C for 3 hours to prepare liquid ammonium bisulfate, and The obtained ammonia gas is recovered with water to prepare ammonia water.

[0059] According to the mass ratio of ammonium bisulfate / alumina in fly ash to 7.2, weigh ammonium sulfate and fly ash for sintering. The sintering temperature is 320°C and the sintering time is 3.0 hours. ℃, the dissolution rate of aluminum oxide in the obtained ammonium aluminum sulfate solution was 92%. After removing impurities such as iron from the ammonium sulfate solution, the ammonium aluminum sulfate solution was evaporated and crystallized. The obtained aluminum ammonium sulfate crystals are dissolved and prepared into a 0.19mol / L aluminum ammonium sulfate solution, which is fed into ammonia gas for reaction, NH 3 The molar ratio to aluminum ammonium sulfate is 3.2, the reaction temperature is controll...

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Abstract

The invention relates to a method for extracting aluminium oxide from pulverized fuel ash. The method comprises the following steps of: finely grinding the pulverized fuel ash, and then carrying out deferrization treatment; carrying out pyrolysis on ammonium sulphate to prepare ammonium bisulfate and ammonia gas; dissolving out a solid generated after sintering, and then obtaining a solution containing ammonium aluminum sulfate; crystallizing the solution containing the ammonium aluminum sulfate to obtain solid ammonium aluminum sulfate; dissolving the solid ammonium aluminum sulfate and thenpreparing the dissolved solid ammonium aluminum sulfate into a solution reacting with the ammonia gas or ammonia water to generate trihydrate alumina or ammonium sulfate; and roasting the trihydrate alumina to obtain the aluminium oxide. By using the method for extracting aluminium oxide from pulverized fuel ash in the invention, ammonium bisulfate is prepared and the ammonia gas is coproduced, thus, the reaction between the ammonium sulfate and the pulverized fuel ash is convenient to control; and the method is simple, few in side products and easy to realize industrial application.

Description

technical field [0001] The invention relates to a method for extracting alumina, in particular to a method for extracting alumina from fly ash. Background technique [0002] my country's main energy comes from thermal power plants, which produce a large amount of fly ash. The existing methods of using fly ash are mainly brick making or building materials, etc., but the main components of fly ash are alumina and silicon oxide. Bauxite resources in my country are gradually in short supply, so the utilization of fly ash has a very broad prospect. [0003] Fly ash is a substance with pozzolanic properties. The methods for extracting alumina from fly ash can be divided into two categories: alkaline method and acid method. Alkali method includes limestone sintering method and soda lime sintering method. At present, there are many researches on the treatment of fly ash by alkali method. The main disadvantages of alkali method for extracting alumina from fly ash are long process flo...

Claims

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Application Information

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IPC IPC(8): C01F7/30
Inventor 张开元
Owner 北京世纪地和控股有限公司
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