Sodium silicate, commonly known as Paohua alkali, is an inorganic substance with a chemical formula of Na2O·nSiO2. Its aqueous solution is commonly known as water glass, which is a mineral binder. It is a soluble inorganic silicate with a wide range of uses.

Sodium silicate, commonly known as sodium silicate, is a water-soluble silicate, and its aqueous solution is commonly known as water glass, which is a mineral binder. Its chemical formula is R2O·nSiO2, where R2O is an alkali metal oxide, and n is the ratio of silicon dioxide to the number of moles of alkali metal oxide, which is called the molar number of water glass. Water glass commonly used in construction is an aqueous solution of sodium silicate (Na2O nSiO2). The mixing ratio of quartz sand and alkali, that is, the molar ratio of SiO2 and Na2O, determines the modulus n of sodium silicate. The modulus shows the composition of sodium silicate. The modulus is an important parameter of sodium silicate, generally between 1.5 and 3.5 between. The larger the modulus, the harder it is to dissolve solid sodium silicate in water. When n is 1, it can be dissolved in normal temperature water. When n increases, it needs hot water to dissolve. When n is greater than 3, it needs steam above 4 atmospheres to dissolve. The larger the modulus of sodium silicate, the more silica content, the viscosity of sodium silicate increases, it is easy to decompose and harden, and the cohesive force increases. Therefore, sodium silicate with different modulus has different uses. Widely used in general casting, precision casting, papermaking, ceramics, clay, mineral processing, kaolin, washing and many other fields.

Classification

According to the state of matter, it can be divided into two categories: liquid sodium silicate and solid sodium silicate.

liquid sodium silicate

Liquid Na2O·nSiO2 is distinguished according to the different proportions of quartz sand and alkali and the different types of alkali. The appearance is viscous liquid, and the color of different grades has obvious differences, changing from colorless to gray-black. There are ① neutral Na2O nSiO2, ② basic Na2O nSiO2, ③ weakly alkaline Na2O nSiO2, and ④ composite Na2O nSiO2.

Solid Sodium Silicate

Solid Na2O·nSiO2 is an intermediate product, and its appearance is mostly light blue. The Na2O nSiO2 formed by dry casting is blocky and transparent, and the Na2O nSiO2 formed by wet water quenching is granular and can be used only when it is transformed into liquid Na2O nSiO2. Common Na2O·nSiO2 solid products are: ① massive solid, ② powdery solid, ③ instant sodium silicate, ④ zero-hydrate sodium metasilicate, ⑤ pentahydrate sodium metasilicate, ⑥ ortho-sodium silicate

Product Usage

Uses of Sodium Silicate:

① Sodium silicate is the most valuable filler in soap making industry. Adding sodium silicate into laundry soap can buffer the alkalinity of laundry soap, reduce the loss of laundry soap in water, and can enhance washing ability and prevent soap from rancidity ; ② Sodium silicate plays a role in building, anti-corrosion and foam stabilization in synthetic detergents; ③ It can be used as a filler for papermaking; ④ It is used to make silicone gel and silica gel; Connect sand and clay to make various molds and cores that adults need.

Uses of water glass:

① Water glass coated on the metal surface will form alkali metal silicate and SiO2 gel film, so that the metal will not be corroded by external acids and alkalis; ② Used as an adhesive to bond glass, ceramics, asbestos, wood, plywood etc.; ③ used in the manufacture of refractory materials, white carbon black, and acid-resistant cement; ④ used in the textile industry as a slurry, impregnating agent, used as a fixing agent and mordant in textile dyeing and embossing, and used in silk fabrics Add weight; ⑤ Add water glass in leather production, and its dispersed colloidal SiO2 is used to produce soft leather; ⑥ It can be used to preserve eggs in the food industry to prevent microorganisms from entering the eggshell space and causing deterioration; ⑦ In the sugar industry, water glass It can remove the pigment and resin in the sugar solution.