2.4-module, 3.3-module 100% Powder, liquid, solid block，Potassium silicate CAS 1312-76-1

What is potassium silicate? What are its uses?

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. Keep in a sealed, moisture-proof container and do not allow contact with acids.

The product is classified by area of application, typically including: industrial grade (for industrial applications such as welding electrodes, fire-retardant coatings, inorganic coatings, and detergents; typically in the form of liquid potassium silicate, calibrated by modulus and Baumé), food grade (used as a food additive within permitted regulatory limits, such as EU E560), and reagent grade (for laboratories). The impurity control requirements are different in various grades, especially in 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 and iron content

Water-insoluble matter reflects the total amount of impurities, while iron content affects the color of the product and the quality of the coating; both must be controlled within a reasonable range.

7. Heavy metal limits

Food-grade products must keep heavy metals (such as lead and arsenic) within the legal limits to ensure the safety of food additives.

II. What are all the uses of Potassium silicate?

Potassium silicate, with its unique properties of "inorganic binding + inorganic film formation, non-flammability and high temperature resistance", is widely used in welding, fire protection, coatings, daily chemicals, refractories, civil engineering, electronics, food and laboratory fields. All its uses are listed below in order of application field (without omission):

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

Potassium silicate is an excellent inorganic binder for welding electrode coatings and electrode coatings. It helps the coating powder to bond and form, enhances the structural strength and stability of the welding electrode, and ensures that the coating melts evenly during welding. It is an indispensable core raw material for welding electrode production.

2.Fire-retardant coatings and agents (core industrial applications in the field of fire safety)

Potassium silicate itself is non-flammable and is used as a film-forming base material for fire-retardant coatings and fire retardants. It helps the coating to be non-flammable when exposed to fire and forms a heat-insulating protective layer. It is widely used in fire-retardant coatings for steel structures, fireproof boards and inorganic fire-retardant materials, and is a key application for fire safety.

3.Inorganic coatings and floor paint base materials (industrial grade, architectural coatings)

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

4.Detergent and cleaning agent components (daily chemical detergent industry, industrial grade)

Potassium silicate is used as an alkaline cleaning component in various potassium soaps, detergents, and cleaning agents to help regulate alkalinity, disperse dirt, and prevent redeposition. It is widely used in laundry powders, liquid detergents, and industrial cleaning agents.

5.Refractory material binder (refractory materials field, industrial grade)

Potassium silicate is used as a binder in refractory castables, refractory mortars, and high-temperature ceramic adhesives, helping refractory materials maintain strength and integrity at high temperatures, serving high-temperature industries such as steel, glass, and cement.

6.Ceramic & High Temperature Adhesives (Ceramic Industry, Industrial Grade)

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

7. Casting Sand Binders (Industrial Grade, Foundry Industry)

Potassium silicate is used as a binder for foundry sand and cores and is used to help shape the sand mold and has sufficient strength and collapsibility to serve the foundry industry.

8.Soil consolidation and foundation reinforcement (civil engineering field, industrial grade)

Potassium silicate is used as a solidifying agent for soil stabilization and foundation grouting. When combined with calcium chloride and other substances, it is injected into the soil to help reinforce the foundation, prevent seepage and stop water, and is widely used in foundation treatment and tunnel seepage prevention projects.

9.Concrete accelerator (industrial grade, building materials)

Potassium silicate is used as a component of 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, industrial grade)

Used as a binder for the coating layer (phosphor coating) of fluorescent screens. Used as a binder component for carbon electrodes and lead cores. In the past it found extensive application in the manufacture of cathode ray tube fluorescent screens and electronic materials.

11. Protective coating for metals (industrial grade, for metal protection) to prevent from rust

Potassium silicate is applied as an anti-rust protective coating on steel and metal structures, promoting dense adherence of the coating and isolation of corrosive media, hence it is used in the industry of steel structure protection.

12.Water treatment and softening agents (water treatment, industrial grade)

Potassium silicate is used as water softener and scale inhibitor in water treatment, and can help to soften water quality and inhibit scale formation. It is suitable for industrial water treatment and water supply industry.

13. Raw materials for agricultural silicon-potassium fertilizer (agricultural sector, industrial grade)

Potassium silicate is a raw material for silicon-potassium fertilizers and foliar fertilizers, which can help crops supplement silicon and potassium nutrition, improve stress resistance, and can be used in facility agriculture and soil improvement.

14.Paper making and paper coating (industrial grade, papermaking industry)

Potassium silicate is used as an adhesive in paper coating and paper treatment to assist in the improvement of paper strength and surface properties for the specialty paper and packaging paper industries.

15.Food additives (food sector, core food-grade applications, regulatory approval)

Potassium silicate is added as food additive (e.g. E560 anti-caking agent and carrier) within the limits allowed by EU and other regulations to help prevent clumping of powdered foods and improve food processing performance. It must meet the purity thresholds required by food regulations.

16. Laboratory applications like reagent grade (research and analysis, core reagent grade applications)

The potassium silicate of reagent grade is used as a standard solution of silicon, analytical reagent and raw material for research on inorganic materials in laboratories. It is used for silicon content analysis, material synthesis and method development, which is used for scientific research and quality testing.

Note that all grades and specifications are not equal to "risk-free": Potassium silicate liquid is strongly alkaline . Protective gloves , goggles and protective clothing must be worn during handling to avoid contact with skin and eyes . Food applications must not exceed the regulatory limits . Raw materials of any grade of product must not be directly consumed . Waste liquid must be neutralized and disposed of in accordance with regulations .

Potassium silicate (K2SiO3, CAS No. 1312-76-1) is a colorless to pale yellow transparent viscous liquid or glassy solid. It is easily soluble in water and is strongly alkaline. With its dual functions of inorganic bonding and inorganic film formation, it is used in welding, fire protection, coatings, daily chemicals, refractories, civil engineering, electronics, food and laboratory fields. In daily life, we encounter potassium silicate through fire-retardant coatings, inorganic wall coatings, welded steel structures, detergents, ceramic products, some foods, foundation engineering, and water treatment. In applications, potassium silicate is widely used in welding electrode adhesives, fire-retardant coatings and agents, 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 agents, agricultural potassium silicate fertilizer raw materials, paper coatings, food additives (licensed), and reagent-grade laboratory applications. It is a versatile inorganic binder connecting "silicate chemistry" with "welding, fire protection, coatings, daily chemicals, refractories, civil engineering, electronics, food, and scientific research."