Low cost method for preparing SiO2 aerogel micro-sphere

Abstract

This invention discloses a method for preparing SiO2 aerogel micro-balls with low cost. Low price sodium silicate is used as raw material to produce silicate with pH=2-3 by using ion-exchange, adding catalyst, then being dropped into a vessel containing oil, and hydrophobic matter in the botton. The silicate drops from ball shape due to the surface tension in oil. The drops fall onto the bottom with hydrophobic matter, keep also the ball shape, and stay for a certain time to obtain aquogel micro-balls, which are then separated from oil and water washed, solvent-exchanged by ethanol to obtain alcogel micro-ball; finally, the later are dried to obtain millimeter grade aerogel of SiO2. The advantages are: simple process, achieving commercial production, low cost, able to be recovery of the oil, the product is expected to be used as thermal insulation material or in catalyst field.

Description

technical field [0001] The invention belongs to the field of inorganic non-metallic materials, relates to a nanoporous material, in particular to a low-cost preparation of SiO 2 Airgel microspheres approach. Background technique [0002] SiO 2 Airgel is a new type of solid material with nanoporous structure formed by the mutual aggregation of nanoparticles. It has the characteristics of low density, high porosity, large specific surface area, uniform distribution and good light transmission performance. It is very useful in many fields. The wide application prospect has been highly valued by material researchers and other researchers. [0003] Currently, on the preparation of SiO 2 There are many reports on aerogels, but the final products prepared are mostly blocks or powders of different sizes. SiO 2 Airgel bulk materials have the defects of being brittle and brittle and difficult for practical application, while powdered SiO 2 In practical applications, aerogels wil...

AI Technical Summary

Problems solved by technology

However, based on the necessary drop time as a reason for the reaction time of the gel, the overall height of the hydrogel to be injected would be very large

In order to reduce the height of the equipment, the patent No. 98805632.1 "Preparation method of near-spherical lyogel and aerogel" has further improved it. Adding lyosol to the steam not only accelerates the gel reaction, but also The glue time is shortened, and the falling direction of the liquid droplets is opposite to the direction of the steam flow, so the falling speed of the liquid droplets is reduced, and finally the height of the equipment is reduced, but the equipment and method used in this invention are still relatively complicated

Another SiO 2 Airgel pellets and TiO 2 / SiO 2 The preparation method of airgel microspheres also has some disadvantages. On the one hand, silica sol is used as the silicon source, which is more expensive. On the other hand, the first three patents use n-heptane or n-hexane, Span 80, Tuwen 85, n-butanol or n-hexanol are used as raw materials to prepare the oil phase, and the last patent uses ammonia water, cetyl ammonium bromide saturated solution and kerosene to prepare the oil phase, which not only makes the oil phase components complicated and the preparation process More cumbersome, and some chemical reagents may also cause environmental pollution problems