Properties and uses of pentahydrate, nonahydrate, and anhydrous sodium metasilicate

Sodium metasilicate is an inorganic substance with the chemical formula Na2SiO3. It is a white granular crystal. It is a low molecular crystal produced by the hydrothermal reaction of ordinary bubble alkali and caustic soda. It is easily soluble in water and soluble in dilute sodium hydroxide solution. Insoluble in ethanol and acid. The products include anhydrous, pentahydrate and nonahydrate, among which nonahydrate only exists in the Chinese market—mainly used as analytical reagents, fabric fire retardants, adhesives, hardeners, weighting agents, fillers, and also used in ore floatation and petroleum refining.

Properties and uses of anhydrous sodium metasilicate

Properties of Anhydrous Sodium Metasilicate

Anhydrous sodium metasilicate is a salt of silicic acid, an inorganic salt product, with the molecular formula Na2SiO3·nH2O. It is a non-toxic, odorless, pollution-free white powder or crystalline particle—easily soluble in water and dilute alkali, insoluble in alcohol and acid. Aqueous solutions are alkaline.

Uses of anhydrous sodium metasilicate

  1. Laundry detergent builder. ISS and 4A zeolite are complementary in function. They can completely replace STPP in laundry detergent when mixed in a reasonable ratio. It can be used to produce ordinary washing powder through spray drying of the ingredients beforehand, or it can be used as base powder to produce concentrated washing powder by agglomeration method. The product has good fluidity, no agglomeration or agglomeration, and has strong detergency.
  2. Laundry paste and laundry detergent auxiliaries. It is compatible with surfactants and bleaches and does not hydrolyze or precipitate.
  3. Meal washing builder. The oil absorption value is as high as 70%, and its oil removal ability replaces hydrated sodium metasilicate (oil absorption value 38%).
  4. Industrial cleaning agent additives. ISS is an important component of various cleaning agents such as metal cleaning agents, heavy oil cleaning agents, oil pipeline cleaning agents, wine and milk bottle cleaning agents, etc. It has strong detergency and, anti-corrosion and anti-rust effects.
  5. Clean the oil stain directly. ISS can clean oil stains without surfactant and can be directly mixed into an aqueous solution of appropriate concentration.
  6. Ceramics, cement, refractory materials, grinding aids and reinforcing agents. ISS has a unique condensation-reducing and depolymerizing effect. The grinding production of ceramics, cement, and refractory materials can effectively shorten the fine grinding time and improve the strength of the embryo and the cement grade.
  7. Cement additives and dispersants for construction.
  8. Electroplating rust removal polishing agent and PH value buffering agent.
  9. Cotton yarn steaming, paper bleaching, fabric finishing agent.
  10. Used as adhesive and cement dispersant in crude oil, natural gas and underwater drilling projects.
  11. Metal anti-corrosion and anti-rust agent.
  12. Blast furnace maintenance and masonry adhesive.
  13. Additives for the production of special lubricants and thixotropic agents.
  14. Glass reinforcing agent.

Properties and uses of sodium metasilicate pentahydrate

Properties of sodium metasilicate pentahydrate

Among the varieties of sodium metasilicate, the most commonly used and most typical one is sodium metasilicate pentahydrate. The molecular formula of its crystal is usually written as Na2SiO3·5H2O. It is the tetrahydrate of disodium dihydrogen orthosilicate with two cations. Material, solubility (20℃) 50g/100g water, melting point 72℃. Sodium metasilicate pentahydrate has the general characteristics of sodium silicate and sodium metasilicate. It has a certain binding capacity for calcium and magnesium ions, especially the binding capacity for magnesium ions is greater than 260mgMgCO3/g (35℃, 20min).

Uses of sodium metasilicate pentahydrate

  1. Washing aid:Sodium metasilicate can be easily mixed with other commonly used diluents such as soda ash, phosphate, sodium humate, etc. to form a diluting degumming agent, which has better degumming performance than a single degumming agent. Sodium metasilicate pentahydrate has strong wetting, emulsifying and saponifying effects on fatty substances and has strong oil removal properties. It is widely used in the preparation of various detergents and is the best substitute for sodium tripolyphosphate.
  2. Metal surface treatment:Silicates will hydrolyze in water. The silicic acid generated by hydrolysis is insoluble in water and suspended in the bath liquid with a micelle structure. This solvated micelle has the ability to suspend and absorb solid dirt particles. Dispersion ability, emulsifying oil dirt, thus helping to prevent redeposition of dirt on the surface of the workpiece. Silicates have a buffering effect; that is, their pH value stays almost unchanged in the presence of acidic dirt. Silicates can also form precipitates with high-valent metal ions in the water, remove iron salts in the water, and complex calcium and magnesium ions, which, in a certain sense, soften water. Silicates also have corrosion resistance and are metal corrosion inhibitors. Therefore, almost all alkaline cleaning agents used for non-ferrous metals, especially aluminum, zinc, tin and other parts, contain silicates.
  3. Ceramic grinding aid: The reason why sodium metasilicate has a diluting effect is that it can increase the surface charge density of micelles in the mud, thereby increasing the double electric layer and ξ potential and increasing the repulsive force between particles at the same time, the silicate anions contained in sodium metasilicate can form insoluble substances with Ca2+ and Mg2+ harmful ions in the mud, promote the exchange of Na+, reduce the viscosity of the mud, and increase the fluidity. Especially suitable for ceramic mud grouting forming additives.
  4. Fire retardant raw materials, deinking agent raw materials, plastic and water retaining agents.

Properties and uses of sodium metasilicate nonahydrate

Properties of sodium metasilicate nonahydrate

The molecular formula of sodium metasilicate nonahydrate is Na2SiO3·9H2O. The crystal water content reaches 58%, the solubility (20℃) is 38g/100g water, but the dissolution speed is fast; the melting point is 41.6℃, and crystallization will be released at 30~40℃. water, which brings inconvenience to use; during storage, the phenomenon of autolysis and hardening is serious. Sodium metasilicate nonahydrate is used in large quantities in ceramics and many other industries that do not require crystallization water. The market is relatively stable, with an annual demand of 70,000 to 100,000 tons.

What are the uses of sodium metasilicate nonahydrate?

  1. Used as analytical reagents, fabric fire retardants, adhesives, hardeners, weight increasing agents, and fillers.
  2. Used in mineral flotation and petroleum refining.
  3. The Adhesive industry is used as an adhesive for corrugated paper, cardboard, adhesive board, wood, packaging, refractory, and building materials.
  4. Used in the chemical industry to manufacture silicates, silica gel, silica sol, molecular sieves, white carbon black, silicon-alumina catalysts, etc.
  5. Used in the foundry industry to manufacture grinding wheels and sand foundry.
  6. In the textile industry, it is used for bleaching, dyeing and sizing of textiles. It is also used as a scouring aid for cotton cloth and a stabilizer for hydrogen peroxide bleaching.
  7. In the detergent industry, it is widely used as a heavy-duty detergent. It can form a precipitate with heavy metal ions to soften water and prevent dirt from redepositing on clothes. It also has corrosion inhibition, wettability and emulsification properties; it also has corrosion inhibition, wettability and emulsification properties. Especially used as a cleaning aid for hard surfaces.
  8. It can be used for fireproofing wood, extending the storage period of eggs, and as an efficient detergent and water softener. Used in toothpaste as an anti-corrosion agent for aluminum tubes.
  9. It can also be used as a soil stabilizer, rubber waterproofing agent, paper bleaching agent, cutting coolant rust inhibitor, soap filler, metal preservative, etc., and refractory materials, ceramic production, food antisepsis, etc.


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