Technology for extracting silicon dioxide from Al2O3 extracted slag of fly ash

A technology for extracting aluminum and silicon dioxide from fly ash is applied in the removal of silicon dioxide, silicon oxide, solid waste, etc. The effect of saving resources and low alkali consumption

Inactive Publication Date: 2015-03-11
XINYI TIANYUE QUARTZ
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, there are not many processes that can extract and separate all the alumina and silica in fly ash, and produce high value-added alumina and silica products.
[0003] Especially after the fly ash extracts alumina, the remaining waste residue is close to 60% of the fly ash raw material, of which the silicon dioxide content is as high as 85%. In the prior art, a process of directly preparing cement from the fly ash acid extraction aluminum slag is proposed , although it is industrially feasible, this process not only has poor economic benefits and low added value of products, but also cannot be fully utilized locally due to the large output, so it cannot realize comprehensive utilization of fly ash with high added value

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Clean the residual slag cake (fly ash aluminum extraction slag) after acid leaching reaction to extract alumina from fly ash to neutral, and use it to prepare SiO 2 products, including the following processes:

[0019] (1) Concentrated alkali leaching: After mixing 100 parts by weight of the aluminum extraction slag cake with 1000 ml of 40% NaOH solution, react at 110° C. for 90 min, then add hot water to make the NaOH solution generated 2 SiO 3 Fully dissolved to form sodium silicate solution, after filtration and separation, Na 2 SiO 3 Solution and alkali leaching reaction residue;

[0020] (2) Carbon content and iron removal: the secondary carbon content method is adopted, and the Na content mentioned in the carbon content is 2 SiO 3 solution, so that the purity of the precipitated silica is higher, and the precipitated SiO 2 The iron content in the medium is high, and the SiO is cleaned with 5% HCl 2 Remove the iron from it, then wash the SiO with distilled w...

Embodiment 2

[0024] Clean the residual slag cake (fly ash aluminum extraction slag) after acid leaching reaction to extract alumina from fly ash to neutral, and use it to prepare SiO 2 products, may also include the following processes:

[0025] (1) Concentrated alkali leaching: After mixing 150 parts by weight of the aluminum extraction slag cake with 1000 ml of a 50% NaOH solution, react at 120°C for 80 minutes, then add hot water to make the NaOH solution generated 2 SiO 3 Fully dissolved to form sodium silicate solution, after filtration and separation, Na 2 SiO 3 Solution and alkali leaching reaction residue;

[0026] (2) Carbon content and iron removal: the secondary carbon content method is adopted, and the Na content mentioned in the carbon content is 2 SiO 3 solution, so that the purity of the precipitated silica is higher, and the precipitated SiO 2 High iron content in medium, clean SiO with 15% HCl 2 Remove the iron from it, then wash the SiO with distilled water 2 to n...

Embodiment 3

[0030]Clean the residual slag cake (fly ash aluminum extraction slag) after acid leaching reaction to extract alumina from fly ash to neutral, and use it to prepare SiO 2 products, may also include the following processes:

[0031] (1) Concentrated alkali leaching: After mixing 200 parts by weight of the aluminum extraction slag cake and 1000 ml of NaOH solution with a concentration of 60%, react at 115° C. for 120 min, then add hot water to make the NaOH solution generated 2 SiO 3 Fully dissolved to form sodium silicate solution, after filtration and separation, Na 2 SiO 3 Solution and alkali leaching reaction residue;

[0032] (2) Carbon content and iron removal: the secondary carbon content method is adopted, and the Na content mentioned in the carbon content is 2 SiO 3 solution, so that the purity of the precipitated silica is higher, and the precipitated SiO 2 High iron content in medium, clean SiO with 30% HCl 2 Remove the iron from it, then wash the SiO with dist...

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Abstract

A technology for extracting silicon dioxide from Al2O3 extracted slag of fly ash comprises the step of cleaning the Al2O3 extracted slag of the fly ash obtained via an acid leaching reaction to be neutral, and further comprises the steps: (1) concentrated alkali leaching: mixing a slag cake and an NaOH solution for reaction for 80-120min at 110-120 DEG C, adding hot water to sufficiently dissolve generated Na2SiO3 into a sodium silicate solution, obtaining an Na2SiO3 solution and alkaline leaching reaction residue after filtration and separation, (2) carbonation and ferrum removal: carbonating the Na2SiO3 solution to form a precipitate SiO2, cleaning SiO2 with HCl at a concentration of 5-30% to remove ferrum from SiO2, then cleaning with distilled water to be neutral to form SiO2 with upper purity, (3) low-temperature drying: drying SiO2 after the ferrum removal for a certain time at 70 DEG C to form SiO2 powder with a particle size of about 10 micrometers, and (4) causticization: causticizing an Na2CO3 solution formed by carbonating the Na2SiO3 solution with CaO, and allowing generated CO2 gas to return to the carbonation technology and CaO to return to the causticization technology.

Description

technical field [0001] The invention relates to a silicon dioxide extraction method, in particular to a method for extracting silicon dioxide from fly ash aluminum extraction slag. Background technique [0002] Fly ash is a solid waste discharged from power plants and is one of the largest sources of pollution in today's society. The content of aluminum and silicon in fly ash is very high. If the aluminum in fly ash can be extracted through a simple process, it can not only solve the pollution problem caused by the accumulation of a large amount of fly ash, but also turn waste into treasure. Become a cheap secondary resource. Extracting alumina and silica from fly ash not only has good environmental and social benefits, but is also technically feasible. However, at present, there are not many processes that can extract and separate all the alumina and silica in fly ash to produce high value-added alumina and silica products. [0003] Especially after the fly ash extracts ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/12B09B3/00
Inventor 张婷婷雷绍民张勋张凤凯徐腾
Owner XINYI TIANYUE QUARTZ
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