The application of silica sol in refractory materials

Silica sol is widely used in the refractory industry as a binder for silica refractory fibers, refractory insulating bricks, and acid and alkali resistant cement.

Mullite-bonded corundum refractory materials are prepared by using plate-shaped corundum as the aggregate, mullite as the bonding phase, and the reaction sintering process.

To improve the mechanical properties of multiphase refractory materials, mullite is synthesized using SiO2 micro-powder as the silicon source, and silica sol is introduced to partially replace SiO2 micro-powder.

The results show that the introduction of silica sol can promote the synthesis of mullite, make the microstructure more uniform and dense, and significantly improve the strength and high-temperature creep resistance of the material.

When sintered at 1550℃, the flexural strength of the sample prepared by replacing 4% (mass fraction, the same below) SiO2 fine powder with silica sol is 40.16% and 29.92% higher than that of SiO2 fine powder at room temperature and high temperature, respectively

When fired at 1650℃, the creep resistance of the former is 71% lower than that of the latter. The load-deformation test results show that the room-temperature fracture process of mullite-bonded hard refractory materials is gradual, and the introduction of silica sol improves the room-temperature fracture toughness of refractory materials to a certain extent.

Using silica sol as the binder, its performance will not deteriorate at high temperatures because the binder is a low-melting-point oxide. At high temperatures, a needle-like columnar secondary mullite network structure can be formed, thus having advantages such as high-temperature resistance, high-temperature strength, and large high-temperature volume. It has good stability and good resistance to sudden temperature changes.

The invention relates to the field of ceramic forming products based on silicate, particularly to a manufacturing method of fireproof and heat-insulating fiberboard. The base material is common alumina-silicate fiber or high alumina fiber slag, and 0-60% (by weight) of high-silica alumina powder is added as filler according to the need. An appropriate amount of silica sol is added as inorganic binder, and cationic starch and carboxymethyl cellulose are added as organic binders. After adding an appropriate amount of water, the mixtureis processed through the procedures of mixing, forming and drying to obtain sheet materials; or an appropriate amount of white latex is added to the mixture, and the mixtureis processed through the procedures of mixing, forming, special-shaped processing, extrusion and drying to obtain special-shaped fiberboard.