1. What is sodium silicate?
Sodium silicate, that is, water glass, is a soluble alkali metal silicate material combined by alkali metal oxide and silicon dioxide, also known as sodium silicate. Its chemical formula is R2O nSiO2, where R2O is an alkali metal oxide, and n is the molar ratio of silicon dioxide to alkali metal oxide, which is called the modulus of water glass. Sodium silicate (Na2O NSIO 2) is usually used in buildings.
Second, the main characteristics of sodium silicate
1. High adhesion and strength.
After water glass is hardened, its main components are silica gel and solid, and its specific surface area is large, so it has high adhesion. However, the quality of sodium silicate, batch properties and construction maintenance have significant effects on the strength.
2. Good acid resistance
It can resist almost all inorganic and organic acids except hydrofluoric acid (HF), hot phosphoric acid and higher fatty acids.
3. Good heat resistance
After hardening, the strength of the silicon mesh skeleton hardly decreases at high temperature. The heat resistance can reach 1000℃ when sodium silicate mortar and concrete are prepared with heat-resistant and refractory aggregate. Therefore, the heat resistance of sodium silicate concrete can also be understood as mainly depending on the heat resistance of aggregate.
4. Poor alkali resistance and water resistance
Sodium silicate cannot be used in alkaline environment, because it is easily soluble in alkali after being mixed with water. Similarly, NaF and Na2CO3 are both soluble in water, so they are not water-resistant. However, the hardened sodium silicate can be treated with moderate concentration of acid to improve water resistance.
Third, the use of sodium silicate.
1. Improve weather resistance.
After coating or impregnating the material with water glass solution, it can penetrate into cracks and pores, and the cured silica gel can block capillary channels, improve the density and strength of the material, and thus improve the weather resistance of the material. Soaking or brushing porous materials such as clay brick, cement concrete, silicate concrete and stone with the density of 1.35g/cm3 can improve the compactness, strength, impermeability, frost resistance and water resistance of the materials. However, sodium silicate should not be used for painting or impregnating gypsum products. Sodium silicate reacts with gypsum to produce sodium sulfate (Na2SO4), which crystallizes and expands in the pores of products, resulting in cracking and damage of gypsum products.
Reinforce soil
Sodium silicate and calcium chloride solution are alternately injected into the soil, and the two solutions react quickly to form silica gel and calcium silicate gel, which play the role of cementing and filling pores and improve the strength and bearing capacity of the soil. It is often used to strengthen the foundation of silt, sand and fill, which is called double liquid grouting.
3. Preparation of quick-setting waterproof agent
Sodium silicate can be mixed with a variety of alum to make a quick-setting waterproof agent, which can be used for local emergency repair such as plugging and joint filling. The setting speed of this multi-alum waterproof agent is very fast, usually a few minutes, and the four-alum waterproof agent does not exceed 1min, so it must be ready-to-use when used in the construction site.
There are four kinds of alum commonly used as multi-alum waterproofing agent, namely, bile alum (copper sulfate), red alum (potassium dichromate, K2Cr2O7), alum (also known as alum and potassium aluminum sulfate) and purple alum.
4. Preparation of acid-resistant gel
Acid-resistant gelling is made of sodium silicate and acid-resistant powder (commonly used quartz powder). Like acid-resistant mortar and concrete, it is mainly used in projects with acid-resistant requirements. Such as a sulfuric acid tank.
5. Preparing heat-resistant mortar
Sodium silicate cementation is mainly used for building and repairing refractories. Sodium silicate heat-resistant mortar and concrete are mainly used in structural parts with heat-resistant requirements such as blast furnace foundation.
6. Anti-corrosion engineering application
Modified sodium silicate acid-resistant slurry is an important material for acid corrosion resistance, and its main characteristics are acid resistance, temperature resistance, compactness and impermeability, low price and convenient use. It can be mixed with acid-resistant mortar, acid-resistant mortar and acid-resistant concrete, which is suitable for anti-corrosion engineering of various structures in chemical industry, metallurgy, electric power, coal, textile and other departments, and is an ideal material for acid storage tanks, acid-resistant floors and acid-resistant surfaces of spinning acid building structures.
7. Adhesive
In 1950s, sodium silicate blowing carbon dioxide technology was widely used. This process has high sodium silicate addition, poor collapsibility, old sand can not be reused, which wastes silica sand resources, discharges a lot of solid waste, destroys the ecological environment, and the quality of the castings produced is rough and faces elimination.
A new type of ester-hardened sodium silicate self-hardening sand 1999 came out. When sodium silicate 1.8-3.0% was added, it had high strength and good collapsibility. The used sand can be recovered with the recovery rate of 80-90% and the service time can be adjusted. It can be used in mechanized molding production line and single piece and small batch production. It can produce various castings ranging from several kilograms to hundreds of tons, and has been widely used in dozens of enterprises such as railway vehicles, metallurgical machinery, heavy machinery, mining machinery and general machinery factory.
The new type of water glass is called green and environment-friendly casting binder which accords with sustainable development.
8. Repair cracks in brick walls
Sodium silicate, granulated blast furnace slag powder, sand and sodium fluorosilicate are mixed in a proper proportion and directly pressed into the cracks of brick walls, which can play a role in bonding and strengthening.
Fourth, the price of sodium silicate.
How much is sodium silicate a ton? This is what many people want to know. The scientific name of sodium silicate is industrial sodium silicate, which is used for the rapid solidification of coatings and cement and has good anti-seepage grouting effect. There are many specifications and models of sodium silicate, which are generally priced according to concentration and modulus. Ordinary 500-900 yuan tons, better 1000 yuan or more, and the freight is generally calculated separately.