The application of silica sol in heat-insulating refractory materials

The series of silica sol products custom-developed for applications in heat-insulating refractory materials possess the characteristics of strong adhesion, excellent corrosion resistance, good thermal shock resistance, and the ability to withstand high temperatures of up to 1600°C. They can serve as binders for refractory materials, thermal insulation materials, etc., enabling the materials to have high strength, good volume stability at high temperatures, and excellent thermal shock resistance. They can also enhance the oxidation resistance and slag erosion resistance of products.

In the current situation of increasingly scarce energy resources, the research on thermal insulation materials has become one of the key technical issues for energy conservation and consumption reduction. Increasing the service temperature of heat-insulating refractory materials can reduce or even eliminate the working layer. Therefore, the development of heat-insulating refractory materials for use at high temperatures has attracted much attention. Mullite lightweight refractory materials, due to their excellent properties such as high temperature resistance, low creep rate, and high load softening temperature, are widely used in industries such as metallurgy, glass, ceramics, chemistry, power, gas, and cement. At the same time, higher service temperatures also pose higher requirements for the selection of binders. Currently, most thermal insulation materials use cement as a binder. However, the addition of cement has an adverse effect on the high-temperature strength of the castables. Silica sol is a colloidal dispersion liquid formed by dispersing nano-SiO₂ particles in an organic solvent. It is a binder for refractory materials used at high temperatures, overcoming the disadvantage that cement binders are overly sensitive to temperature. At the same time, the highly active nano-SiO₂ particles in the silica sol react with active alumina micro powder at high temperatures to form mullite whiskers, increasing the bonding strength of the samples.

There are also more industrial applications as follows:

1. When making ceramic furnaces, silica sol is used as a binder for ceramic fibers. The aluminum silicate fiber felt is impregnated with silica sol, and a setting accelerator is added to make a thermal insulation felt, which plays the role of thermal insulation.

2. When silica sol is added to cookware, it makes the cookware non-flammable, smokeless, and environmentally friendly.

3. When making transformer cores, silica sol is used as a binder to bond the silicon steel sheets into one piece, and it can also play the roles of insulation and high temperature resistance.

4. When making silicon steel, adding a certain amount of silica sol to the coating solution can improve the appearance of the insulating coating, its insulating performance and heat resistance, reduce the expansion coefficient of the coating material, and improve the magnetic properties of the silicon steel.

The series of product models custom-developed by Huihe for applications in refractory and high-temperature-resistant materials include S-1430, S-40, TS-515, SW-30, and SW-25. As binders for refractory materials, thermal insulation materials, etc., they have been widely used in the above-mentioned various industries. Verified by large-scale usage, they have excellent comprehensive performance, good usage effects, stable quality, and are highly recognized and praised by a large number of users.