Introduction to Liquid Potassium Silicate
Liquid potassium silicate is an inorganic compound composed of potassium oxide (K₂O) and silicon dioxide (SiO₂). Its chemical formula is typically represented as K₂O·nSiO₂, where n represents the molar ratio of SiO₂ to K₂O, known as the modulus. Liquid potassium silicate is the aqueous solution form of potassium silicate, presenting as a viscous transparent or semi-transparent liquid.
The production process of liquid potassium silicate mainly adopts two methods: dry process and wet process. The dry process involves mixing quartz sand and potassium carbonate in a certain ratio, melting and reacting at a high temperature of 1300-1400℃ to form solid potassium silicate, and then dissolving it to obtain the liquid product. The wet process is to heat and react quartz sand with potassium hydroxide solution under pressure conditions directly to produce liquid potassium silicate.
Depending on the modulus, liquid potassium silicate can be classified into low modulus products (modulus 2.0 – 2.5), medium modulus products (modulus 2.5 – 3.2), and high modulus products (modulus 3.3 – 4.0). The modulus size directly affects the performance and application of the products. High modulus products usually have better water resistance and bonding strength.
Physical properties of liquid potassium silicate
Potassium silicate liquid is a colorless or slightly yellow semi transparent to transparent liquid with hygroscopicity. It has a pH value between 11-12 and a relative density between 1.16-1.45 (20 ℃). It has a strong alkaline reaction and decomposes in acid to precipitate silica. Slowly soluble in cold water or almost insoluble in water (depending on its composition), insoluble in ethanol. The larger the modulus, the higher the viscosity and strength of potassium silicate, and the faster the drying speed; The smaller the modulus, the better the film-forming ability of water glass, but the slower the drying speed.
Chemical properties of potassium silicate
In aqueous solution, potassium silicate exists in a complex chemical equilibrium system. Its aqueous solution is strongly alkaline, with a pH value typically ranging from 11 to 13. The silicate ions in the solution undergo hydrolysis reactions, generating corresponding silicic acid and hydroxide ions. The stability of potassium silicate is influenced by various factors. In the air, it reacts with carbon dioxide, gradually precipitating silica, a process known as carbonation. Acidic substances can cause the potassium silicate solution to gel, generating silicic acid gel. Heavy metal salts can also cause the solution to precipitate.
The uses of liquid potassium silicate
1. Application in the paint industry
Liquid potassium silicate is the main base material for inorganic zinc-rich paints. These paints have excellent anti-corrosion properties and are widely used for long-term protection of steel structures such as ships, bridges, and storage tanks. In high-temperature paints, potassium silicate acts as a binder and can withstand temperatures above 400℃.
2. Welding Industrial Applications
As an auxiliary material for welding rods, liquid potassium silicate plays the role of a binder in the manufacturing process of welding rods. It can firmly bond the welding powder to the surface of the welding core, ensuring that the coating does not fall off during storage and use of the welding rods. At the same time, it also improves the stability of the electric arc.
3. Application of Building Materials
In the field of building coatings, potassium silicate is used to produce inorganic exterior wall coatings. These coatings have excellent weather resistance, breathability and fire resistance, and are particularly suitable for the protection of historical buildings and the exterior decoration of landmark buildings. As a concrete curing agent, it can effectively enhance the hardness and wear resistance of the concrete surface.
4. Other industrial applications
In the textile industry, liquid potassium silicate is used as a flame-retardant treatment agent for fabrics. In precision casting, it is an important component of the sand mold binder. The production of welding rods cannot do without the application of potassium silicate as a binder. In addition, it is also used in the manufacture of products such as silica gel, soap fillers, and fertilizers.
Storage and transportation of liquid potassium silicate
Liquid potassium silicate should be stored in sealed containers to prevent prolonged contact with air. Plastic containers or stainless steel containers are recommended, while aluminum containers should be avoided as the alkaline potassium silicate solution will react with aluminum. The storage temperature should be maintained between 5 and 40 degrees Celsius to prevent freezing or evaporation at high temperatures. The storage location should be well-ventilated to avoid direct sunlight. The product should be stored separately from acids, oxidants, and other chemicals. The storage container should be clearly marked with the product name, specifications, production date, etc.
Transportation of liquid potassium silicate must comply with chemical transportation management regulations. The transportation vehicle should have measures to prevent leakage and keep the container sealed. During transportation, it should be avoided from direct sunlight, rain, and high-temperature environments. Acidic substances and other items should not be mixed for transportation. Loading and unloading operations should be carried out gently to prevent damage to the packaging. The transportation personnel should receive professional training to understand the product characteristics and emergency handling methods. During long-distance transportation, the container condition should be checked regularly to ensure transportation safety.
Under storage conditions, the shelf life of liquid potassium silicate is usually six months. Products beyond the shelf life require re-inspection. They can be used if they are found to be qualified. If the product shows abnormal phenomena such as gelation or precipitation, it should be stopped from use and professional technical guidance should be sought.
Overall, liquid potassium silicate is an important inorganic chemical raw material with unique physical and chemical properties and a wide range of application fields. Correctly understanding its characteristics and properly selecting and using the product are crucial for ensuring the final product quality. At the same time, strictly adhering to storage and transportation regulations and ensuring safe production and use are the prerequisite guarantees for maximizing the value of liquid potassium silicate. With the advancement of technology and process improvement, liquid potassium silicate will continue to provide reliable material support for various industries in the future.
