Method for preparing silicon dioxide and aluminum oxide from coal ash

A technology of silicon dioxide and fly ash, applied in the directions of silicon dioxide, silicon oxide, alumina/aluminum hydroxide, etc., can solve the problem of unsatisfactory uniformity of solid raw materials, high metal ion content in sodium silicate liquid, equipment and Operators have high requirements to achieve the effect of high added value of products, reduced production costs, and simplified impurity removal procedures

Active Publication Date: 2011-03-30
CHINACOAL PINGSHUO GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patented technology involves reducing or eliminating problems associated with traditional methods used on coal burning facilities by developing cost-effectively efficient processes that use less expensive materials while maintaining good results over time. Additionally, it provides an effective way to recover acid mist from exhaust gases without generating excess water pollution during disposal procedures. Overall, this new method offers technical benefits for efficiently producing highly pure green ceramics at lower prices than current options.

Problems solved by technology

This patented technical problem addressed in this patents relates to improving efficient usage of flyash resources while minimizing negative effects such as increased disposal costs due to excessive landfills caused by burning them away without being reused.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0028] A certain proportion of fly ash, sodium carbonate, calcium oxide and water are put into the airtight reaction vessel, in which 500 g of fly ash, the molar ratio of sodium carbonate and calcium oxide is 3, the mass ratio of fly ash and calcium oxide is 2, and the liquid The solid ratio is 4, after 30 minutes of alkali dissolution at a temperature of 180°C and a pressure of 0.9 MPa, the sodium silicate solution, desilication fly ash and calcium carbonate solid mixture are separated by filtration, the solid mixture is washed, and the desilication ash is dried;

[0029] Sodium silicate solution enters CO 2 Carbon is used to prepare silicon dioxide, a solid mixture of partially desiliconized fly ash and calcium carbonate is mixed with cement and foaming agent with water to prepare foamed concrete.

[0030] The partially desiliconized fly ash and calcium carbonate solid mixture are prepared by soda lime sintering method to prepare alumina, and the waste residue after preparing alum...

Embodiment approach 2

[0032] A certain proportion of fly ash, sodium carbonate, calcium oxide and water are put into the airtight reaction vessel, in which 500 g of fly ash, the molar ratio of sodium carbonate and calcium oxide is 3, the mass ratio of fly ash and calcium oxide is 2, and the liquid The solid ratio is 4, at 240°C and 1.2MPa pressure, after 30 minutes of alkali dissolution, filtered to separate the sodium silicate solution, desilication fly ash and calcium carbonate solid mixture, wash the solid mixture, and dry the desilication ash;

[0033] Sodium silicate solution enters CO 2 Carbon, silica is prepared, the solid mixture of desiliconized fly ash and calcium carbonate is prepared by soda lime sintering method to prepare alumina, and the waste residue after preparing alumina by soda lime sintering method is used to prepare foamed concrete blocks.

Embodiment approach 3

[0035] A certain proportion of fly ash, sodium carbonate, calcium oxide and water are put into a closed reaction vessel, where fly ash is 500g, the molar ratio of sodium carbonate and calcium oxide is 1, and the mass ratio of fly ash to calcium oxide is 4. The solid ratio is 6. After being dissolved in alkali for 50 minutes at 300°C and 7.2MPa pressure, the mixture of sodium silicate solution, desilication fly ash and calcium carbonate solid mixture is filtered and separated, the solid mixture is washed, and the desilication ash is dried;

[0036] Sodium silicate solution enters CO 2 Carbon content, silica is prepared, the solid mixture of desiliconized fly ash and calcium carbonate is prepared by the soda lime sintering method to prepare alumina, and the waste slag after preparing the alumina by the soda lime sintering method is beaten and used for the purification of coal-fired boiler tail gas.

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PUM

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Abstract

The invention relates to a method for preparing silicon dioxide and aluminum oxide, in particular to a method for preparing silicon dioxide and aluminum oxide from coal ash. In the method, the coal ash, sodium carbonate and calcium oxide are used as raw materials, the sodium carbonate is causticized in situ by the calcium oxide, and is dissolved with alkali in a high-temperature high-pressure reaction system to form sodium silicate, calcium carbonate and desiliconized coal ash solid, wherein the sodium silicate solution is carbonated by CO2 to form silicon dioxide; and aluminum oxide and foam concrete can be prepared from the calcium carbonate and the desiliconized coal ash by a soda lime sintering method. Residues after aluminum oxide preparation can be used as a raw material for preparing a tail gas purification absorbent in cement and chemical plants and coal burning boilers, and the foam concrete. Compared with the prior art, the method has the advantages of weak reacting solution corrosion, high desiliconization rate, low metal content of prepared sodium carbonate and high white carbon black quality, high aluminum oxide extraction rate and the like; meanwhile, the raw material source is wide, the process is simple, the production cost is low, and the product additional value is high.

Description

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Claims

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Application Information

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Owner CHINACOAL PINGSHUO GRP
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