What Kind of Material Is Water Glass? What Is Water Glass Used For?

I. Properties of Water Glass

1. Chemical Properties

   • Water glass is alkaline and can react with acids to form silica gel and corresponding salts.

   • It possesses good adhesion and viscosity.

   • It decomposes into silicon dioxide and sodium carbonate at high temperatures.

   • Water glass solutions dry in air to form a hard, glass-like film.

2. Physical Properties

   • Water glass typically appears as a colorless or slightly yellow transparent liquid.

   • It has high viscosity and density.

   • It is soluble in water but insoluble in alcoholic solvents.

II. Production of Water Glass

The production of water glass typically involves the fusion reaction of silica sand (SiO₂) with soda ash (Na₂CO₃) at high temperatures, generating a mixture of silicon dioxide and sodium carbonate. This mixture further reacts at elevated temperatures to form water glass. During production, controlling the reaction temperature and time allows adjustment of the modulus ratio of water glass (the molar ratio of SiO₂ to Na₂O), thereby influencing its properties.

III. Applications of Water Glass

1. Construction Industry

   • Waterproofing Material: Water glass is commonly used as a waterproofing agent in concrete and mortar. It penetrates the pores of concrete, reacts with calcium ions present to form insoluble calcium silicate, filling the pores and enhancing the concrete's waterproofing performance.

   • Binder: In construction, water glass can serve as a binder for masonry, ceramics, and refractory materials, providing good bonding strength and fire resistance.

2. Chemical Industry

   • Silica Gel Production: Water glass is a crucial raw material for manufacturing silica gel. By reacting with acids, water glass forms silica gel, a material with excellent adsorption properties widely used in desiccants and catalyst carriers.

   • Detergents and Soaps: Water glass is used in the production of detergents and soaps, improving their cleaning power and stability.

3. Textile Industry

   • Textile Treatment: Water glass is used for fireproofing and waterproofing treatments of textiles. By forming a silicate film on the textile surface, it enhances the fabric's fire resistance and durability.

4. Foundry Industry

   • Molding Sand Binder: In the casting process, water glass acts as a binder for molding sand. It increases the strength and refractoriness of the sand, ensuring the dimensional accuracy and shape of castings.

5. Environmental Protection:

   • Wastewater Treatment: Water glass is used in wastewater treatment processes. It reacts with heavy metal ions in the water to form insoluble precipitates, thereby removing heavy metal contaminants.

   • Soil Stabilization: In soil improvement and stabilization, water glass reacts with minerals in the soil to form stable silicate structures, enhancing the soil's load-bearing capacity and stability.

IV. Advantages of Water Glass

1. Versatility: Its chemical properties give water glass broad application potential across multiple fields.

2. Cost-Effectiveness: The production cost of water glass is relatively low, and raw materials are readily available.

3. Environmental Friendliness: As an inorganic material, water glass does not release harmful gases or pollutants during use.

V. Challenges of Water Glass

Despite its many advantages, water glass also presents some challenges during application:

1. Durability: In certain applications, the silicate film formed by water glass may degrade due to environmental factors, affecting its long-term performance.

2. Corrosiveness: Due to its alkalinity, water glass may corrode certain metal materials, requiring careful attention during use.

3. Application Limitations: Some characteristics of water glass may restrict its use in specific environments, such as under high temperatures or acidic conditions.

VI. Future Development

With technological advancement, the application scope of water glass continues to expand. Researchers are exploring modification and composite technologies to enhance its performance and applicability. For instance, the introduction of nanotechnology could improve the bonding strength and durability of water glass. Furthermore, its application in new environmentally friendly materials is being actively explored to meet growing demands for sustainability.

In summary, water glass, as a versatile inorganic material, plays a significant role in multiple fields due to its unique chemical and physical properties. As technology progresses and application needs evolve, the prospects for water glass applications will become even broader.