Method for preparing SiO2-Al2O3 composite aerogel material from fly ash

A technology of composite airgel and fly ash, applied in the field of mesoporous materials, achieves the effect of low cost, short process and short process

Active Publication Date: 2020-01-10
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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  • Method for preparing SiO2-Al2O3 composite aerogel material from fly ash
  • Method for preparing SiO2-Al2O3 composite aerogel material from fly ash
  • Method for preparing SiO2-Al2O3 composite aerogel material from fly ash

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Example 1 (see the process figure 2 )

[0032] (1) Mix the fly ash and sodium hydroxide (mass ratio 1:0.8) uniformly, place them in a muffle furnace, and calcine at 350°C for 2 hours.

[0033] (2) Grind the alkali fusion mixture obtained in step (1), take 5 g of the alkali fusion mixture, add 30 ml of hydrochloric acid (5 mol / L) and 40 ml of deionized water, and stir until the reaction is complete.

[0034] (3) Filter the mixed solution in step (2) to obtain a solution containing silicon and aluminum.

[0035] (4) Add ammonia water (0.25 mol / L) to the solution obtained in step (3) to control the pH of the solution to be 2.7.

[0036] (5) After aging the gel obtained in step (4) for 1 day, wash it twice with deionized water.

[0037] (6) The gel obtained in step (5) is replaced with absolute ethanol for solvent replacement, and dried in an oven at 45°C for 3 hours and at 75°C for 12 hours.

Embodiment 2

[0038] Example 2 (see the process figure 2 )

[0039] (1) Mix the fly ash and sodium hydroxide (mass ratio 1:1) uniformly, and place them in a muffle furnace at 400°C for 1.5 hours.

[0040] (2) Grind the alkali fusion mixture obtained in step (1), take 6 g of the alkali fusion mixture, add 25 ml of hydrochloric acid (5 mol / L) and 30 ml of deionized water, and stir until the reaction is complete.

[0041] (3) Filter the mixed solution in step (2) to obtain a solution containing silicon and aluminum.

[0042] (4) Add ammonia (0.35 mol / L) to the solution obtained in step (3) to control the pH of the solution to be 2.9.

[0043] (5) After aging the gel obtained in step (4) for 2 days, wash it with deionized water three times.

[0044] (6) The gel obtained in step (5) is replaced with absolute ethanol for solvent replacement, and dried in an oven at 45°C for 3 hours, 65°C for 12 hours, and 75°C for 12 hours.

Embodiment 3

[0045] Example 3 (see the process figure 2 )

[0046] (1) Mix the fly ash and sodium hydroxide (mass ratio 1:1.2) uniformly, and place them in a muffle furnace at 500°C for 1 hour.

[0047] (2) Grind the alkali fusion mixture obtained in step (1), take 4 g of the alkali fusion mixture, add 35 ml of hydrochloric acid (5 mol / L) and 35 ml of deionized water, and stir until the reaction is complete.

[0048] (3) Filter the mixed solution in step (2) to obtain a solution containing silicon and aluminum.

[0049] (4) Add ammonia water (0.5 mol / L) to the solution obtained in step (3) to control the pH of the solution to be 3.1.

[0050] (5) After aging the gel obtained in step (4) for 3 days, wash it with deionized water 4 times.

[0051] (6) The gel obtained in step (5) is replaced with absolute ethanol for solvent replacement, dried in an oven at 45°C for 3 hours, 55°C for 6 hours, 65°C for 12 hours, and 75°C for 12 hours.

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Abstract

The invention discloses a method for preparing SiO2-Al2O3 composite aerogel from fly ash, and belongs to the field of mesoporous materials. The preparation method comprises the following steps: uniformly mixing fly ash, used as a raw material, with sodium hydroxide, calcining the obtained mixture in a muffle furnace for a certain time to obtain an alkali fusion mixture, mixing and stirring the alkali fusion mixture and a hydrochloric acid solution, and carrying out solid-liquid separation to obtain a liquid phase containing silicon and aluminum; dropwise adding ammonia water into the liquid phase containing silicon and aluminum at normal temperature under a continuous stirring condition to promote a gel reaction of the liquid phase in order to obtain a wet gel; and ageing the wet gel, washing the aged wet gel with deionized water, and carrying out solvent replacement and normal-pressure drying to obtain the SiO2-Al2O3 composite aerogel. The whole technological process has the advantages of realization of high-added-value utilization of solid waste fly ash, low cost, short process, and realization of the whole preparation period of only 3 days; the specific surface area of the synthesized SiO2-Al2O3 composite aerogel is about 900 m <2>/g; and after the composite aerogel is calcined at 900 DEG C for 2 h, the amorphous structure is still maintained, and the good thermal stabilityis achieved.

Description

Technical field [0001] The invention belongs to the field of mesoporous materials, and particularly relates to the synthesis of SiO with fly ash as a raw material 2 -Al 2 O 3 Method of composite aerogel materials. Background technique [0002] Aerogel is a porous solid material formed by a three-dimensional network structure composed of nanoparticles and filled with air. The porosity can reach 80%-99.8%, the typical pore diameter is 1-100nm, and the specific surface area is usually 200-1200m. 2 / g, the range of density is 0.003-0.5g / m 3 ((1) A. Soleimani Dorcheh, M.H. Abbasi, Journal of Materials Processing Tech, 2008, 199(1-3): 10-26.). Due to these characteristics, aerogels have great application potential in heat insulation materials, heat insulation materials, separation materials, and low dielectric constant materials. [0003] With SiO 2 Or Al 2 O 3 Compared with aerogel, Al 2 O 3 -SiO 2 The composite aerogel has better high temperature performance and thermal stability, and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/158C01F7/06
CPCC01B33/1585C01F7/0693C01P2004/82
Inventor 郭敏申满满张梅
Owner UNIV OF SCI & TECH BEIJING
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