Method for extracting aluminum oxide from fly ash by one-step process

A technology of alumina and fly ash, applied in the direction of alumina/aluminum hydroxide, solid waste removal, etc., can solve the problems of non-compliance with national environmental protection requirements, increased energy consumption, low economic efficiency, etc., and achieve good industrial application prospects , the effect of reducing energy consumption and investment

Active Publication Date: 2012-02-15
西安航天华威化工生物工程有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The alkaline method mainly follows the method of extracting alumina from bauxite. This method has a long process flow, and the amount of residue produced after extracting alumina is several times that of fly ash, which does not meet the national environmental protection requirements; compared with the ac...

Method used

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Examples

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Effect test

Embodiment 1

[0025] The method for extracting alumina in one step from fly ash of the present invention is realized by the following steps:

[0026] Step 1: Fly ash and potassium sulfate are mixed and granulated in sulfuric acid with a mass fraction of 70% according to a mass ratio of 1:1, and the particle size is 1mm; activated by roasting at 400°C, and the roasting reaction time is 0.1 hour, and the obtained The solid is dissolved in water at 60°C and normal pressure, and then filtered to remove the solid residue;

[0027] Step 2: the solution obtained in step 1 is removed by the jarosite method to remove impurity iron in the solution;

[0028] Step 3: The solution obtained in step 2 is cooled and crystallized to obtain solid potassium aluminum sulfate dodecahydrate, and the temperature of cooling and crystallization is lowered from 80°C to 20°C; potassium aluminum sulfate dodecahydrate is roasted at 900°C to obtain alumina, sulfuric acid Potassium and sulfur trioxide, the solid phase i...

Embodiment 2

[0030] The method for extracting alumina in one step from fly ash of the present invention is realized by the following steps:

[0031] Step 1: Mix and granulate fly ash and potassium sulfate in sulfuric acid with a mass fraction of 80% at a mass ratio of 1.5:1, with a particle size of 1mm; activate it by roasting at 500°C for 0.1 hour, and obtain a solid Under the condition of 70 ℃ and normal pressure, the solid residue is removed by filtration after the sulfuric acid with a mass fraction of 30% is dissolved;

[0032] Step 2: the solution obtained in step 1 is removed by the jarosite method to remove impurity iron in the solution;

[0033] Step 3: The solution obtained in step 2 is cooled and crystallized to obtain solid potassium aluminum sulfate dodecahydrate, and the temperature of cooling and crystallization is lowered from 90°C to 30°C; potassium aluminum sulfate dodecahydrate is roasted at 1000°C to obtain alumina, sulfuric acid Potassium and sulfur trioxide, the solid...

Embodiment 3

[0035] The method for extracting alumina in one step from fly ash of the present invention is realized by the following steps:

[0036] Step 1: Mix and granulate fly ash and potassium sulfate in sulfuric acid with a mass fraction of 80% at a mass ratio of 1.5:1, with a particle size of 3mm; activate it by roasting at 600°C, and roast for 2.5 hours to obtain a solid Under the condition of 90 ℃ and normal pressure, the solid residue is removed by filtration after the sulfuric acid with a mass fraction of 45% is dissolved;

[0037] Step 2: the solution obtained in step 1 is removed by the jarosite method to remove impurity iron in the solution;

[0038] Step 3: The solution obtained in step 2 is cooled and crystallized to obtain solid potassium aluminum sulfate dodecahydrate, and the temperature of cooling and crystallization is lowered from 90°C to 30°C; potassium aluminum sulfate dodecahydrate is roasted at 1100°C to obtain alumina, sulfuric acid Potassium and sulfur trioxide,...

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Abstract

The invention relates to a method for extracting aluminum oxide from fly ash by a one-step process. The technique for extracting aluminum oxide from fly ash by an acid-process/alkali-process has the defects of long technological procedure, complex equipment and poor economic performance, and restricts the large-scale application. The method comprises the following steps: mixing fly ash and potassium sulfate in concentrated sulfuric acid to carry out granulation; roasting for activation at certain temperature; dissolving out the solid in water or sulfuric acid to remove solid residues; removing the impurity iron from the solution by a jarosite process; crystallizing the solution to obtain solid potassium aluminum sulfate dodecahydrate; roasting the potassium aluminum sulfate dodecahydrate to obtain aluminum oxide, potassium sulfate solid and sulfur trioxide gas; and washing the solid phase, and filtering to obtain the aluminum oxide product. The potassium aluminum sulfate solid is obtained by cooling crystallization, thereby lowering the energy consumption; the impurities can be effectively removed in the crystallization process, thereby reducing the investment for the impurity removal system; and the potassium sulfate and sulfuric acid can be recycled, so the economic benefit of industrial production is high.

Description

technical field [0001] The invention belongs to the technical field of fly ash treatment, in particular to a method for extracting alumina from fly ash in one step. Background technique [0002] High-aluminum fly ash is a new type of fly ash that has appeared in the central and western regions of Inner Mongolia with the development of coal resources in western my country and the construction of large-scale thermal power plants in recent years, and its Al2O3 content can usually reach about 50% , which is equivalent to the content of Al2O3 in the middle and low grade bauxite in my country. [0003] In recent years, with the rapid development of my country's aluminum industry, the shortage of bauxite and alumina supply has become increasingly prominent. At present, my country's bauxite reserves are only about 2 billion tons, and high-quality bauxite resources are relatively scarce, and most bauxite and alumina need to be imported from abroad. In order to meet the development ...

Claims

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Application Information

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IPC IPC(8): C01F7/02B09B3/00
Inventor 郭坤王辉赵仕哲郭新峰杨鹏梁恺
Owner 西安航天华威化工生物工程有限公司
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