Application of silica sol in refractory materials

Silica sol is widely used in the refractory industry as a binder for silicate refractory fibers, refractory insulation bricks, and acid- and alkali-resistant cement. It uses tabular corundum as the aggregate and mullite as the binding phase, and uses a reaction sintering process to prepare silica sol. Laminated stone combined with corundum refractory material. SiO2 micropowder is used as the silicon source for the synthesis of mullite, and an attempt is made to introduce silica sol to partially replace SiO2 micropowder, aiming to improve the mechanical properties of complex refractory materials. 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 material strength and high temperature creep resistance. 1 When fired at 550°C, the normal and high temperature flexural strength of the sample prepared by replacing 4% (mass fraction, the same below) SiO2 powder with silica sol as the silicon source is 40.16% higher than that of the sample prepared with SiO2 powder as the silicon source. and 29.92%; when fired at 1650°C, the former is 71% lower than the latter in high temperature creep resistance. The load-deformation test results show that the room temperature fracture process of mullite combined with corundum refractory materials is progressive. The introduction of silica sol improvesthe room temperature fracture toughness of the material to a certain extent.

Using silica sol as the bonding agent, the bonding agent will not bring in low-melting point oxides at high temperatures, which will cause its performance to deteriorate. The matrix of the amorphous refractory material is composed of special-grade or first-grade high-aluminum clinker and silica powder. It generates acicular secondary mullite network structure at high temperatures, so it has high and high strength, high-temperature volume stability, and temperature resistance. Good rapid change performance and other advantages.