Sodium silicate
Sodium silicate, also known as: water glass, soda silicate. Chemical formula Na2O.nSiO2
Chemical composition of sodium silicate:
Sodium silicate is a soluble alkali metal silicate material composed of alkali metal oxides and silicon dioxide. Also known as water glass and soda silicate. Their molecular formulas are Na2O.nSiO2. The coefficient n in the formula is called the modulus of sodium silicate, which is the molecular ratio (or molar ratio) of silicon oxide and alkali metal oxides in sodium silicate. The modulus of sodium silicate is an important parameter of sodium silicate, generally between 1.5-3.5. The larger the modulus of sodium silicate, the more difficult it is for solid sodium silicate to dissolve in water. When n is 1, it can be dissolved in normal temperature water. When n is increased, hot water is needed to dissolve. When n is greater than 3, steam with a pressure of more than 4 atmospheres is required to dissolve. . The greater the modulus of sodium silicate, the more silica content, the viscosity of sodium silicate increases, it is easy to decompose and harden, and the bonding force increases.
There are two methods for the production of sodium silicate: dry method and wet method. The dry method uses quartz sand and soda ash (chemical name is sodium carbonate), anhydrous sodium sulfate (also known as Yuanming powder or Glauber's salt), and sodium hydroxide (also known as caustic soda) as raw materials. After stirring evenly, heat it in the furnace at 1300-1400 It melts at ℃ temperature and reacts according to the following formula to generate solid water glass. It is dissolved in water under the steam pressure of 0.4MPa-0.8MPa to prepare liquid water glass.
Wet production uses quartz powder (sand) and caustic soda as raw materials, and performs a pressure steaming reaction in a high-pressure steamer at 2-3 atmospheric pressure to directly generate liquid water glass.
Industrial sodium silicate has different properties due to the different ratios of sodium oxide and silicon dioxide in the molecule. The molecular molar ratio of sodium oxide to silica is called the modulus. Those with a modulus above 3 are called neutral water glass, and those with a modulus below 3 are called alkaline sodium silicate. Its products are usually divided into solid sodium silicate, hydrated sodium silicate and liquid sodium silicate.
Physical properties and form:
Liquid sodium silicate is a colorless or slightly colored transparent or translucent viscous liquid. Solid sodium silicate is a colorless, slightly colored transparent or translucent glass block. There are three forms: liquid, solid, and water quenching.
Uses:
The uses of sodaline are very wide, covering almost all sectors of the national economy. In the chemical industry system, it is used to manufacture various silicate products such as silica gel, white carbon black, zeolite molecular sieve, sodium metasilicate, silica sol, layered silicon and instant powdered caustic soda, potassium sodium silicate, etc. It is a silicon compound basic raw materials. In economically developed countries, there are more than 50 types of deep-processed products using caustic soda as raw materials, some of which have been used in high-tech, sophisticated and cutting-edge technology fields; in light industry, they are an indispensable raw material for washing powder, soap and other detergents. , is also a water softener and sedimentation aid; used in the textile industry to aid dyeing, bleaching and sizing; widely used in the machinery industry for casting, grinding wheel manufacturing and metal preservatives; used in the construction industry to make quick-drying Cement, acid-resistant cement waterproof oil, soil curing agent, refractory materials, etc.; in agriculture, it can be used to make silica fertilizer; in addition, it is used as a silicon-alumina catalyst for petroleum catalytic cracking, a filler for soap, an adhesive for corrugated paper, a metal preservative, a water softener, Detergent additives, refractory materials and ceramic raw materials, textile bleaching, dyeing and sizing, mining mineral processing, waterproofing, leakage plugging, wood fire protection, food antisepsis and adhesive production, etc...