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Method for extracting aluminum oxide from pulverized flue ash

A technology of fly ash and alumina, applied in alumina/aluminum hydroxide and other directions, can solve the problems of difficult reaction, high equipment investment, large material volume, etc., and achieves low corrosion resistance requirements, low equipment corrosion, and residues. small amount of effect

Active Publication Date: 2011-07-13
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

[0004] The present invention is aimed at the existing method of extracting alumina from fly ash, which adopts the alkaline method with long process flow, large amount of material and high investment in equipment, and the red mud produced in the process of extracting alumina is the number of fly ash. times, it needs to be equipped with relevant cement production systems to digest the red mud produced after alumina extraction, and most of the acid methods use sulfuric acid or hydrochloric acid as the production medium, which has the disadvantages of not being easy to react, low extraction rate, and high requirements for equipment anti-corrosion performance. Provide a method for extracting alumina from fly ash

Method used

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  • Method for extracting aluminum oxide from pulverized flue ash
  • Method for extracting aluminum oxide from pulverized flue ash

Examples

Experimental program
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Effect test

Embodiment 1

[0047] Grind the fly ash containing 46% of alumina and 40% of silica to 1000 mesh, weigh ammonium sulfate and fly ash according to the mass ratio of ammonium sulfate / alumina in fly ash to 10.0, and sinter the sintering temperature The temperature is 720°C, the sintering time is 3.5 hours, the sintered clinker is dissolved with water at 98°C under normal pressure, the dissolution rate of alumina in the obtained ammonium aluminum sulfate solution is 87%, and the ammonium aluminum sulfate solution is removed after iron and other impurities , the aluminum ammonium sulfate solution was cooled to 5°C for crystallization for 3 hours, and then the obtained aluminum ammonium sulfate crystals were dissolved to prepare a 0.2mol / L aluminum ammonium sulfate solution, and ammonia gas was introduced to decompose it. The reaction temperature was 35°C, and the reaction After 3 hours, the aluminum hydroxide solid whose particle size is less than 1.5% of the total number of particles that can lea...

Embodiment 2

[0049] Grind the fly ash containing 42% alumina and 40% silica to 200 meshes, weigh ammonium sulfate and fly ash according to the mass ratio of ammonium sulfate / alumina in fly ash to 8.5, and sinter the sintering temperature The temperature is 500°C, the sintering time is 3.5 hours, and the sintered clinker is dissolved with water at 98°C under normal pressure, and the dissolution rate of aluminum oxide in the obtained ammonium aluminum sulfate solution is 89%. After the ammonium sulfate solution is removed from iron and other impurities, Cool the aluminum ammonium sulfate solution to 10°C for crystallization for 5 hours, then dissolve the obtained aluminum ammonium sulfate crystals to prepare a 0.25mol / L aluminum ammonium sulfate solution, then react with ammonia water with a concentration of 25%, and control the reaction temperature to 45 ℃, the reaction time is 2 hours, and the particle size is that the number of particles that can leak through the mesh of 325 mesh accounts ...

Embodiment 3

[0051] Grind the fly ash containing 40% alumina and 43% silica to 800 meshes, weigh ammonium sulfate and fly ash according to the mass ratio of ammonium sulfate / alumina in fly ash to 7.2, and sinter the sintering temperature The temperature is 320°C, the sintering time is 4.0 hours, the sintered clinker is dissolved with water at 98°C under normal pressure, and the dissolution rate of aluminum oxide in the obtained ammonium aluminum sulfate solution is 92%. After the ammonium sulfate solution is removed from impurities such as iron, Cool the aluminum ammonium sulfate solution to 8°C for crystallization for 4 hours, then dissolve the obtained aluminum ammonium sulfate crystals to prepare a 0.19 mol / L aluminum ammonium sulfate solution, and feed ammonia gas to react. The reaction temperature is controlled at 60°C, and the reaction time is After 3 hours, the aluminum hydroxide solid whose particle size is less than 1.8% of the total number of particles that can leak through the 32...

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Abstract

The invention relates to a method for extracting aluminum oxide from pulverized flue ash. The method comprises the following steps of: finely grinding the pulverized flue ash, and deironing; mixing the deironed pulverized flue ash and ammonium sulfate and then sintering to generate solid and ammonia gas; dissolving out the solid generated through sintering, then filtering or settling out, washing to obtain a solution containing aluminum ammonium sulfate; crystallizing the solution containing the aluminum ammonium sulfate to obtain solid aluminum ammonium sulfate; dissolving the solid aluminum ammonium sulfate, then preparing into a solution which reacts with the ammonia gas or ammonia water for 0.5-6h at a temperature of 20-50 DEG C to generate aluminum hydroxide and ammonium sulfate; roasting the aluminum hydroxide to obtain the aluminum oxide. The method for extracting the aluminum oxide from the pulverized flue ash is simple, ensures that less byproduct is produced and is easy to realize industrial application.

Description

technical field [0001] The invention relates to a method for extracting alumina from substances discharged by burning coal in a thermal power plant, in particular to a method for extracting alumina from fly ash. Background technique [0002] my country is a big coal country, and the main energy comes from thermal power plants, which produce a large amount of fly ash every year, which brings huge pressure to environmental protection. The existing methods of dealing with fly ash are mainly brick making or cement production, but since the main components in fly ash are alumina and silicon oxide, it has a very broad prospect of comprehensive utilization. [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 a...

Claims

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Application Information

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IPC IPC(8): C01F7/02
Inventor 张开元
Owner 北京世纪地和控股有限公司
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