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Method for recovering alumina, silica and other metal components from fly ash

A technology of metal composition and silicon dioxide, applied in the direction of alumina/aluminum hydroxide, silicon oxide, etc., can solve the problems of large amount of tailings, high energy consumption, dangerous waste of resources, etc. The effect of short time and high leaching efficiency

Active Publication Date: 2016-04-27
DATANG INT HIGH ALUMINA COAL R & D CENT +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the defects of large amount of tailings, high energy consumption, serious waste of resources or high risk in the resource utilization of existing high-alumina fly ash, and to provide a new A method for recovering alumina, silicon dioxide and other metal components. This method has the advantages of low tailings, low energy consumption, recovery of various resources, and good safety.

Method used

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  • Method for recovering alumina, silica and other metal components from fly ash

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] 1. Pre-desilication of high-alumina fly ash The composition of high-alumina fly ash from Inner Mongolia Tuoketuo Thermal Power Plant is shown in Table 1.

[0022] Table 1 Chemical composition of high alumina fly ash samples

[0023] Element

Al 2 o 3

SiO 2

total iron oxide

TiO 2

CaO

Loss on ignition

the sum

Content (%)

48.45

40.55

1.92

1·54

3.64

1·31

97.41

[0024] Take 150 grams of high-alumina fly ash, put it into a 1-liter high-pressure reactor, and then add sodium hydroxide solution (500 ml of water + 180 g of solid sodium hydroxide). After sealing the reaction kettle, start the stirrer, raise the temperature in the reaction kettle to 140° C., and keep the temperature constant for 1.5 hours. After the temperature in the reaction kettle was cooled to below 80°C, the kettle was opened and the reaction mixture was taken out. Filtrate, wash the filter residue twice with hot water (3...

Embodiment 2

[0030] 1. Pre-desilication of high alumina fly ash

[0031] The chemical composition of high aluminum fly ash is the same as in Example 1.

[0032]Take 150 grams of high-alumina fly ash, put it into a 1-liter high-pressure reactor, and then add sodium hydroxide solution (400 ml of water + 90 g of solid sodium hydroxide). After the reactor was sealed, the stirrer was started, and the temperature in the reactor was raised to 200° C., and the temperature was kept constant for 1.5 hours. After the temperature in the reaction kettle was cooled to below 80°C, the kettle was opened and the reaction mixture was taken out. After filtering, the filter residue was washed twice with hot water (200 ml each time) and then dried for later use; the washing solution was filtered and combined with the dissolution filtrate, and the volume was adjusted to 1000 ml. Silicon molybdenum blue was used to measure the concentration of silicon in the desiliconization solution, and the pre-desilication ...

Embodiment 3

[0038] 1. Pre-desilication of high alumina fly ash

[0039] The chemical composition of high aluminum fly ash is the same as in Example 1.

[0040] Take 150 grams of high-alumina fly ash, put it into a 1-liter high-pressure reactor, and then add sodium hydroxide solution (400 ml of water + 100 g of solid sodium hydroxide). After sealing the reaction kettle, start the stirrer, raise the temperature in the reaction kettle to 180° C., and keep the temperature constant for 1.5 hours. After the temperature in the reactor was cooled to below 50°C, the kettle was opened to take out the reaction mixture. After filtering, the filter residue was washed twice with hot water (200 ml each time) and then dried for later use; the washing solution was filtered and combined with the dissolution filtrate, and the volume was adjusted to 1000 ml. Silicon molybdenum blue was used to measure the concentration of silicon in the desiliconization solution, and the pre-desilication efficiency (that i...

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Abstract

The invention discloses a method of recovering alumina, silica and other metal components from fly ash. The method comprises: (1) removing silicon from the fly ash, (2) adding an additive into the silicon-removed fly ash, (3) dissolving metal components in calcined fly ash clinker by using a dissolving agent to obtain a dissolving slurry, (4) filtering the dissolving slurry, condensing filtrate, then filtering, cooling filtrate, precipitating aluminum ammonium sulfate crystals, recycling a crystallizing mother liquid being used as the dissolving solvent in the step (3), and (5) calcining the aluminum ammonium sulfate crystals to obtain the alumina. According to the invention, a roasting temperature of the silicon-removed fly ash is only 350-450 DEG C, and the method is mild in dissolving condition, high in dissolving efficiency, safe to operate, low in energy consumption, few in tailing amount and good in security, and can recover a plurality of resources.

Description

technical field [0001] The invention relates to a resource utilization method of fly ash, in particular to a method for recovering alumina, silicon dioxide and other metal components from fly ash, and belongs to the field of resource utilization of fly ash. Background technique [0002] In the fly ash produced by thermal power generation, the alumina content reaches 40% to 55%, and the gallium content exceeds 80ppm. Therefore, high-alumina fly ash is not only a huge aluminum resource, but also contains a Gallium resources, the development of high aluminum fly ash, is an effective way to protect the environment and recycle resources. At present, the resource utilization technology of high alumina fly ash mainly includes limestone sintering method (Chinese patent application publication number: CN102351226A, publication date: February 15, 2012) and pre-desilication-soda lime sintering method (Chinese patent application publication No.: CN101284668A, date of publication Octobe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/02C01B33/113
Inventor 孙俊民王毅张生公彦兵梁振凯许学斌
Owner DATANG INT HIGH ALUMINA COAL R & D CENT
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