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Method for preparing SiO2 aerogel by compounding flyash and kieselguhr

A technology of diatomite and fly ash, which is applied in the directions of silicon oxide and silicon dioxide, can solve the problems of high preparation cost and long production cycle, and achieve the effect of reducing production cost and simple production process.

Inactive Publication Date: 2012-06-27
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In order to overcome the shortcomings of high preparation cost and long production cycle of existing airgel materials, the present invention provides a method for preparing silicon airgel materials at low cost

Method used

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  • Method for preparing SiO2 aerogel by compounding flyash and kieselguhr
  • Method for preparing SiO2 aerogel by compounding flyash and kieselguhr
  • Method for preparing SiO2 aerogel by compounding flyash and kieselguhr

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Embodiment 1

[0015] 50g of fly ash was activated in a muffle furnace at 800°C for 60min; 50g of diatomite was roasted in a muffle furnace at 600°C for 3h, mixed with fly ash and added to 500mL of 10% NaOH solution at 80°C Reaction at low temperature for 150min, filter to take the filtrate, dilute with distilled water at a ratio of 1:1, pass through a cationic resin, control the pH to 2-3, titrate with ammonia water to pH=5.5, age the obtained hydrogel at 30°C, and then wash with ethanol , n-hexane, and trimethylchlorosilane for solvent exchange / surface modification, the molar ratio of ethanol to trimethylchlorosilane is 2:3, the volume ratio of trimethylchlorosilane to wet gel is 1:1, and the time is 24h . Then place it in an oven at 80°C for 2 hours, and dry it at 150°C for 1 hour to obtain SiO 2 Airgel with a specific surface area of ​​531.7m 2 / g, the density is 0.129g / cm 3 , The average pore diameter of the internal micropores is 25nm.

Embodiment 2

[0017] 70g of fly ash, 50g of diatomaceous earth, activated in a muffle furnace at 700°C for 70min; In a 15% NaOH solution, react at 90°C for 120 minutes, filter the filtrate, dilute it with distilled water at a ratio of 1:2, pass through a cationic resin, control the pH to 2-3, and titrate with ammonia water to pH = 6.0, and the obtained water coagulates The gel was aged at 30°C, and then solvent exchange / surface modification was carried out with ethanol, n-hexane, and trimethylchlorosilane. The molar ratio of ethanol to trimethylchlorosilane was 1:1, and trimethylchlorosilane and wet gel The volume ratio is 1:1.5, and the time is 48h. Then place it in an oven at 80°C for 4 hours, and dry it at 150°C for 1 hour to obtain SiO 2 Airgel with a specific surface area of ​​548.4m 2 / g, the density is 0.105g / cm 3 , The average pore diameter of the internal micropores is 18nm.

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Abstract

The invention provides a method for preparing a SiO2 aerogel by compounding flyash and kieselguhr. The method comprises six steps of mechanically activating the flyash and the kieselguhr at intermediate temperature, preparing a SiO2 sol, preparing a wet gel, ageing a mother solution, performing one-step solvent exchange for surface modification, and drying under normal pressure. The obtained SiO2 aerogel has properties similar to an aerogel material taking water glass as a silicon source; and the flyash and the kieselguhr are compounded to serve as a cheap silicon source and a normal pressure drying process is adopted, so that the production cost is greatly reduced, and the SiO2 aerogel has a wider application prospect in the fields such as building materials, thermal insulation, environment-friendly absorption and the like.

Description

technical field [0001] The invention relates to a compound preparation of SiO by fly ash and diatomite 2 The invention relates to an airgel material method, which belongs to the field of functional material preparation. Background technique [0002] SiO 2 Airgel is a new type of amorphous solid material composed of nanometer-scale particles and air as the dispersion medium. It has a nanostructure (1-100nm for holes, 1-20nm for skeleton particles), low volume density (0.01- 0.2g / cm 3 ), large specific surface area (up to 800 ~ 1000m 2 / g), high porosity (up to 80% ~ 99.8%), low thermal conductivity (single particle airgel at room temperature: 0.013 ~ 0.02W / m K, airgel particle accumulation: 0.4W / m 2 K) and other characteristics, it has broad application prospects in the fields of thermal insulation materials, optics, acoustics, electricity, catalysis, drug carriers, and adsorption materials. However, due to the sharp increase in thermal conductivity of silica airgel mate...

Claims

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Application Information

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IPC IPC(8): C01B33/16
Inventor 王宝民宋凯
Owner DALIAN UNIV OF TECH