Soluble glass, also called foam alkali, is an alkali metal air hardening material. In construction, it is usually used to prepare sodium silicate cement, soluble glass mortar, and soluble glass concrete. Soluble glass is widely used in the anti-acid and heat-resistant engineering. The main method to produce soluble glass is to grind and stir calcined soda and quartz sand which are the major raw materials, then fuse them in the melting pot of 130O-140OnC, and finally cool them into solid soluble glass.
Considering the differences of alkali metal oxide, soluble glass can be divided into sodium silicate and potassium silicate, and sodium silicate is often used. Among the components of sodium silicate (Na2O*nSiO2), the ratio of silicon oxide molecules to sodium oxide molecules is known as the module of soluble glass, generally between 1. 5 to 3. 5. And the number of module decides the properties and performance of soluble glass. The solid soluble glass with low module is relatively easy to dissolve in water.
The bigger the number is, the higher the viscosity is and the harder it dissolves in water; the soluble glass with low module, there are many kinds of crystal composition and the cohesive force is poor, and when the module number improves, the colloid component increases and the cohesive force rises. Soluble glass solution can be mixed with water in any proportion. Different amount of water will lead to solutions of different density and viscosity. For the soluble glass solutions with the same module, the higher the density is, the stronger the cohesive force is.
If urea is added into soluble glass, its cohesive force can be improved without modifying the viscosity. Soluble glass also has strong acid corrosion that can resist the majority of inorganic acids, organic acids, and corrosive gases. The silicate gel precipitating during the hardening of soluble glass can block the capillary porosity of the material to prevent water infiltration. Soluble glass has good heat resistance, so it does not dissolve and its strength does not decrease and even increases at a high temperature.
In addition, the soluble glass can burn eyes and skin to a certain extent, so the security protection is needed. Applications of Soluble Glass: •Acid-proof Material Soluble glass can be used as binding material to prepare acid-proof plaster, acid-proof mortar, and acid-proof concrete which are commonly used in anti-acid projects. •Heat-resistant Material Soluble glass has a good heat resistance that can bear a certain high temperature and its strength does not increase.
Thus, it can be made into heat-resistant concrete and mortar. •Coating Soluble glass solution can be used to paint building materials or immerging porous materials. It can enhance the density and strength of materials and increase their resistance to weathering when infiltrating into the materials. But the solution cannot be used to paint or immerge gypsum products because soluble glass can react with gypsum to generate sodium sulfate crystals which will expand in pores and destroy the gypsum products.