Sodium Silicate
Description:
- Can appear as colorless, transparent solids (flakes or powder) or a viscous liquid depending on the water content.
- Odorless.
- The solid form readily absorbs moisture from the air and can clump.
Uses:
Sodium silicate has a wide range of applications due to its unique properties:
- Binder and adhesive: Used in various cements, mortars, and grouts for its adhesive and hardening properties.
- Coating: Applied to surfaces like textiles, paper, and wood for fireproofing, waterproofing, and dustproofing.
- Desiccant: The dehydrated form acts as a drying agent to absorb moisture from the air.
- Detergent builder: In some cleaning products, it helps soften water and improves cleaning performance.
- Food additive: Used in some controlled amounts as an anticaking agent or clarifying agent.
- Other uses: Found in foundry applications, metal cleaning, and certain ceramics production.
Chemical Composition:
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The general formula is Na2O x SiO2, where x represents the ratio of sodium oxide to silicon dioxide. Common forms include:
- Sodium metasilicate (Na2SiO3) – most common form, used in many applications.
- Sodium orthosilicate (Na4SiO4)
- Sodium pyrosilicate (Na6Si2O7)
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The specific ratio can affect the properties of the sodium silicate, such as its viscosity and solubility.
Physical Properties:
- Density: Varies depending on the water content and specific composition (typically between 1.5-2.6 g/cm3).
- Solubility in Water: Solubility varies based on the ratio. Sodium metasilicate is the most soluble form.
- Melting Point: Decomposes before melting.
Safety Information:
- Sodium silicate is a mild alkali and can irritate skin, eyes, and respiratory system upon contact.
- Wear gloves, eye protection, and long sleeves when handling sodium silicate, especially concentrated solutions.
- Inhaling dust or mists can cause respiratory irritation.
- Avoid prolonged or repeated contact with skin.
- Keep out of reach of children and pets.
Additional Information:
- The specific properties and safety considerations for sodium silicate can vary depending on the water content and the ratio of sodium oxide to silicon dioxide.
- Always consult the Safety Data Sheet (SDS) for the specific type of sodium silicate you are using for detailed safety information.
- Sodium silicate solutions can react with acids to form a gel.
