Method for preparing silica aerogel using industrial solid waste fly ash and silica aerogel prepared by the method

A silicon dioxide and industrial solid waste technology, applied in chemical instruments and methods, solid waste management, aluminum hydroxide preparation, etc., can solve problems such as industrial solid waste fly ash environmental pollution, and achieve high-value utilization 、Solve the effect of high preparation cost and low thermal conductivity

Active Publication Date: 2022-07-08
中建材科创新技术研究院(山东)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The main purpose of the present invention is to provide a method for preparing silica airgel by using industrial solid waste fly ash and the silica airgel prepared by the method. The technical problem to be solved is how to efficiently recycle industrial solid waste The siliceous component in waste fly ash solves the environmental pollution problem of industrial solid waste fly ash and at the same time realizes the high-value utilization of industrial solid waste fly ash and increases the added value of industrial solid waste fly ash At the same time, the raw material cost of silica airgel is greatly reduced; and the performance of silica airgel prepared by this method is good, and its specific surface area is as high as 600-800m 2 / g, the thermal conductivity is as low as 0.012-0.016W / (m k); the method can efficiently extract each component, and can form a co-production process that is economically suitable and has high added value of the product, so it is more suitable for practical use

Method used

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  • Method for preparing silica aerogel using industrial solid waste fly ash and silica aerogel prepared by the method
  • Method for preparing silica aerogel using industrial solid waste fly ash and silica aerogel prepared by the method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0075] The fly ash is vibrated and sieved through a 100-mesh standard sieve, and then a magnetic separator is used to magnetically separate and separate the magnetic substances in the fly ash. The composition of fly ash after magnetic separation is as follows: in terms of mass percentage, silica 54.76%, alumina 24.56%, calcium oxide 4.85%, ferric oxide 4.79%, titanium dioxide 1.85%; the rest is loss on ignition The amount and components that have no effect on the process and product are not listed here.

[0076] Add water and stir the above-mentioned powder material after magnetic separation to dissolve it into a slurry with a mass concentration of 20%. After stirring for 10 minutes under the condition of 300 r / min, let it stand for stratification, and separate and extract the bleach in the fly ash. Beads and precipitation ash components; the floating beads are collected and used for other purposes; the precipitation ash is dried at 100 ° C for 2 hours, and the dry powder is g...

Embodiment 2

[0084] In the pretreatment of fly ash, the concentration of the slurry prepared during washing was 25%. After stirring for 8 minutes at 300 r / min, it was left to stand for stratification, and the floating beads and ash components of fly ash were separated and extracted. Dry at 105°C for 2.5h, and grind the dry powder for later use.

[0085] In the pre-desilication treatment, a sodium hydroxide solution with a mass concentration of 25% needs to be prepared, and the liquid modulus of the water glass obtained by the treatment is 0.68; the filter cake is dried at a temperature of 105 ° C for 2.5 hours, and the dried powder is ground for later use. The modulus of water glass is increased to above 3.0, and dilute sulfuric acid with a concentration of 2 mol / L is added for acid catalysis to obtain a silica wet gel.

[0086] The thermal activation of the auxiliary agent is to weigh a certain amount of desilication slag and sodium carbonate according to the mass ratio of 1:0.9, mix the ...

Embodiment 3

[0091] In the pretreatment of fly ash, the concentration of the slurry prepared during washing is 30%. After stirring for 10 minutes at 300 r / min, it is left to stand for stratification, and the floating beads and ash components of fly ash are separated and extracted. Dry at 110°C for 3 hours, and grind the dry powder for later use.

[0092] In the pre-desilication treatment, a sodium hydroxide solution with a mass concentration of 30% needs to be prepared, and the liquid modulus of the water glass obtained by the treatment is 0.75; the filter cake is dried at a temperature of 110 ° C for 3 hours, and the dried powder is ground for later use. The modulus of water glass is increased to above 3.0, and dilute sulfuric acid with a concentration of 6 mol / L is added for acid catalysis to obtain a silica wet gel.

[0093] The thermal activation of the auxiliary agent is to weigh a certain amount of desiliconization slag and sodium carbonate according to the mass ratio of 1:1, mix the...

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Abstract

The invention provides a method for preparing silica aerogel by using industrial solid waste fly ash and the silica aerogel prepared by the method. The method includes: grinding and magnetic separation of fly ash to obtain pre-treated powder; adding sodium hydroxide to the pre-treated powder for reaction; filtering to obtain a first filtrate and a first filter residue; and concentrating the first filtrate to obtain water glass liquid; the first filter residue is dried and ground to obtain the first powder; the first powder auxiliary is thermally activated; dilute sulfuric acid is added to it to dissolve and hydrolyze it; The modulus of water glass is adjusted, and dilute sulfuric acid is added thereto to obtain a silica wet gel; the silica wet gel is aged, replaced with a solution, surface modified, and dried to obtain a silica aerogel. The technical problem to be solved is how to efficiently use the ghost components in industrial solid waste fly ash to prepare silica aerogel, which realizes the high-value utilization of fly ash and reduces the raw material cost of silica aerogel. .

Description

technical field [0001] The invention belongs to the technical field of resource utilization of solid waste materials, and particularly relates to a method for preparing silica aerogel by utilizing industrial solid waste fly ash and a silica aerogel prepared by the method. Background technique [0002] Due to its excellent properties of high porosity, high specific surface area, low density, low thermal conductivity, and low dielectric constant, silica aerogel has attracted extensive research and application internationally in recent years. Expensive chemicals such as ethyl orthosilicate, silica sol and water glass are used as silicon sources, and the supercritical drying technology used is relatively complex, with high equipment cost and high risk, which restricts the large-scale commercialization of aerogel materials. production and application. Therefore, the search for cheap, efficient and environmentally friendly raw materials has become an inevitable trend in the curre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/158C01B33/159C01B33/152C01B33/154C01F7/34C01D5/00
CPCC01B33/1585C01B33/159C01B33/152C01B33/154C01F7/34C01D5/00C01P2006/12C01P2006/16C01P2006/32C01P2006/90Y02W30/91
Inventor 王明铭张忠伦辛志军
Owner 中建材科创新技术研究院(山东)有限公司
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