100% Potassium silicate CAS 1312-76-1

What is potassium silicate? What are its industrial applications?

1. What is Potassium silicate?

Potassium silicate (commonly called potassium water glass or potassium silicate) is a silicate produced by the combination of potassium oxide and silicon dioxide. It is an important inorganic binder and coating base in industry. Its chemical formula is usually written as

K2SiO3 (K2O·nSiO2, CAS No.: 1312-76-1, potassium silicate/potassium water glass)

A colorless to pale yellow transparent viscous liquid (it may also be a glassy solid), readily soluble in water, insoluble in ethanol, and strongly alkaline (its solution in water has a high pH). It decomposes in the presence of acid to give silicon dioxide. The solubility of potassium silicate and its properties depend on the amount of potassium present. The greater the potassium content, the greater the solubility. Solubility increases with increasing potassium content. It is produced by the industrial high-temperature melting or the hydrothermal reaction of potassium carbonate and quartz sand.

Potassium silicate is made up of a framework of silicon-oxygen tetrahedra (SiO4) with potassium ions (K+) to balance the charge. In water it forms a colloidal system having binding, film forming, waterproofing and high temperature resistance properties. After drying, it becomes a strong inorganic film and can also chemically bond to substrates like metals, glass, and ceramics. This is a dual functional material of “inorganic bonding +inorganic film formation”.

Potassium silicate is chemically stable, non-flammable, non-toxic, heat resistant, weather resistant and has strong adhesion. It does not burn after film formation, therefore it is a core raw material for fire-retardant coatings and welding electrode adhesives. It must be kept in an airtight, moisture-proof container. It must not come in contact with acids.

“Industrial grade potassium silicate” means products used for industrial purposes such as (but not limited to) welding electrodes, fire-retardant coatings, inorganic coatings and detergents. Typical specifications are liquid potassium silicate (specified by modulus and Baume). Industrial-grade products pay attention to the following indicators:

1. Modulus (SiO2/K2O molar ratio)

Modulus is the most critical specification of potassium silicate, determining its adhesion, film-forming properties, and solubility. Different applications have different modulus requirements, and the appropriate modulus must be selected accordingly.

2. Potassium oxide content (K2O)

The potassium oxide content determines alkalinity and solubility, affecting product performance and application effects, and must be strictly controlled.

3. Silica content (SiO2)

Silica content determines film-forming properties and adhesion strength, and together with modulus, constitutes the core indicators of the product.

4. Density (Baumé)

Density reflects the concentration of liquid products and is a routine factory inspection indicator that must be maintained consistent across batches.

5. Alkalinity (pH value)

Alkalinity reflects the strong alkalinity of the product, which affects its compatibility with the substrate and safety of use, and must be controlled within the indicated range.

6. Water-insoluble matter

Water-insoluble matter reflects the total amount of impurities, affecting product transparency and bonding quality, and must be controlled within an extremely low range.

7. Iron content

Iron content affects the color of products and the quality of coatings, and must be controlled within a reasonable range.

What are the applications of industrial-grade Potassium silicate?

Industrial grade potassium silicate is used in welding, fire protection, coatings, daily chemicals, refractories, civil engineering and electronics with the unique properties of "inorganic bonding + inorganic film formation, non-flammability and high temperature resistance". All its uses below (and without omission):

1.Electrode adhesive (core application in the welding industry)

Potassium silicate is very good inorganic binder for covering of welding electrodes and covering of electrodes. It helps in bonding and formation of the coating powder, adds to structural strength and stability of the welding electrode and ensures uniform melting of the coating during welding. It is an important basic raw material for the production of welding electrodes.

2. Fire-retardant coatings and agents (important applications in fire protection)

Potassium silicate is non-flammable and is used as a film-forming base for fire retardant coatings and fire retardants. Luckily, the coating is not flammable in case of fire and forms a heat-insulating protective layer. It is widely used in fire-proof coating of steel structure, fire-proof board and inorganic fire-retardant material, which is a key application for fire safety.

3. Floor paint base materials and inorganic coatings (architectural coatings field)

Potassium silicate is the core base material of mineral inorganic coatings (silicate coatings, diatomaceous earth, floor paint), which makes the coating chemically bond with the substrate, weather-resistant and durable, non-flammable and environmentally friendly, and has a wide application prospect in building interior and exterior walls, floors and industrial floor coatings.

4. Detergent and cleaning agent components (daily chemical cleaning industry)

Potassium silicate is an alkaline cleaning ingredient used in many potassium soaps, detergents and cleaning agents to help control alkalinity, disperse soils and prevent redeposition. It is commonly found in laundry powders, liquid detergents and industrial cleaning agents.

5.Refractory material binders (refractory materials field)

Potassium silicate is used as a binder for refractory castables, refractory mortars and high temperature ceramic adhesives. It helps refractory materials maintain strength and integrity at high temperatures and serves high temperature industries such as steel, glass and cement.

6.Ceramics & High Temperature Adhesives (Ceramic Industry)

Potassium silicate is used as a binder for ceramic blanks and glazes and as a high-temperature adhesive to help ceramic products retain their strength during molding and firing. It is also used for ceramic repair and high temperature bonding.

7. Foundry sand binder (foundry industry)

Potassium silicate is used as a binder in foundry sand and cores to create the sand mold and to give the foundry industry the required strength and collapsibility.

8. Soil consolidation and foundation fortification (sector of civil engineering)

Potassium silicate is used as a solidifying agent for soil stabilization and foundation grout. It is injected into the soil with calcium chloride and other substances to strengthen the foundation, prevent seepage and block water, and is widely used in foundation treatment and tunnel seepage prevention projects.

9.Concrete accelerator (building materials industry)

Potassium silicate is used in concrete quick-setting agents to help concrete set and harden quickly, serving applications in shotcrete and emergency repair projects.

10. Coatings for fluorescent screens and electronic materials (electronics industry)

Potassium silicate is used as a binder for the coating layer (phosphor coating) of fluorescent screens, and as a binder component for carbon electrodes and lead cores. It has been widely used historically in manufacture of cathode ray tube fluorescent screens and electronic materials.

11. Protective coatings for metal rust prevention (metal protection field)

Potassium silicate is applied to steel and metal structures as a rust-proof protective coating, which causes the coating to be densely attached and isolated from corrosive media, thus serving the field of steel structure protection.

12.Water treatment and water softening aids (water treatment area)

Potassium silicate is used in water treatment as a water softener and scale inhibitor, helping to soften the quality of water and to inhibit the formation of scale. It is used in the industrial water treatment and water supply industries.

13. Raw materials for silicon-potassium fertilizer for agriculture (agriculture)

Potassium silicate is a raw material for preparation of silicon-potassium fertilizer and foliar fertilizer, which help crops to supplement silicon and potassium nutrition, improve stress resistance and serve facility agriculture and soil improvement.

14. Papermaking and paper-coating (papermaking industry)

Potassium silicate is used as an adhesive in paper coating and paper treatment to help improve paper strength and surface properties, serving the specialty paper and packaging paper industries.

Note that industrial-grade specifications do not mean “risk-free”: liquid potassium silicate is highly alkaline, and protective gloves, goggles and protective clothing should be worn during operation to avoid contact with the skin and eyes; industrial-grade products are strictly forbidden for consumption and waste liquid should be neutralized and disposed of according to regulations.

Summarize

Potassium silicate (K2SiO3, CAS No. 1312-76-1) is a viscous liquid or glassy solid, colorless to pale yellow and transparent. It is soluble in water and is strongly alkaline. It has become an important inorganic material in the industrial field because of the dual functions of inorganic binding and inorganic film formation. In daily life, potassium silicate is used in fire retardant coatings, inorganic wall coatings, welded steel structures, detergents, ceramic products, foundation engineering and water treatment. Potassium silicate is used in a wide range of applications, including welding electrode adhesives, fire-retardant coatings and fire retardants, inorganic coatings and floor paint base materials, detergent components, refractory material adhesives, high-temperature ceramic adhesives, foundry sand adhesives, soil solidification and foundation reinforcement, concrete quick-setting agents, fluorescent screen coatings, metal anti-rust coatings, water treatment softening aids, agricultural potassium silicate fertilizer raw materials and paper coatings. It is a universal inorganic adhesive that connects “silicate chemistry” with “welding, fire protection, coatings, daily chemicals, refractories, civil engineering, electronics, and agriculture”.