Sodium silicate
[CAS# 1344-09-8]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Silicide and silicate
• Name: Sodium silicate
• Synonyms: Sodium orthosilicate; Silicic acid sodium salt
• Molecular Formula: Na₂SiO₃
• Molecular Weight: 122.06
• CAS Registry Number: 1344-09-8
• EC Number: 215-687-4
• SMILES: [O-][Si](=O)[O-].[Na+].[Na+]

Properties

• Density: 1.39 g/mL (25 ºC)

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Hazard Statements: H290-H302-H314-H315-H318-H319-H335
• Precautionary Statements: P234-P260-P261-P264-P264+P265-P270-P271-P280-P301+P317-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P351+P338-P305+P354+P338-P316-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P363-P390-P403+P233-P405-P406-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Serious eye damage	Eye Dam.	1	H318
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H302
Skin corrosion	Skin Corr.	1B	H314
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Skin corrosion	Skin Corr.	1A	H314
Skin corrosion	Skin Corr.	1C	H314
Specific target organ toxicity - single exposure	STOT SE	3	H336
Skin corrosion	Skin Corr.	1	H314
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Skin sensitization	Skin Sens.	1	H317
Acute toxicity	Acute Tox.	4	H332
Eye irritation	Eye Irrit.	2	H318
Carcinogenicity	Carc.	1B	H350
Acute toxicity	Acute Tox.	4	H312

Discovory and Applicatios

Sodium silicate, commonly known as waterglass or liquid glass, is an inorganic compound with the chemical formula Na2SiO3 or Na2Si2O5, depending on its specific form. Its discovery dates back to the 19th century, and early uses date back to the development of the first silicate glasses and cements. The compound was identified through the reaction of sodium carbonate with silica or sand, which produced a soluble form of silica that can be used in various industrial processes.

Sodium silicate is a widely used compound that is available in both solid and liquid forms. The solid form is usually a white or colorless glassy substance, while the liquid form is a clear, viscous solution. The compound is soluble in water to form an alkaline solution with a pH between 11 and 13. Sodium silicate is known for its adhesive properties, thermal stability, and ability to form gels and precipitates.

Sodium silicate is widely used in various industries due to its unique properties. In construction, sodium silicate acts as a binder and hardener in cement and concrete formulations. It improves the strength and durability of concrete by promoting the formation of a dense, impermeable structure. This application is particularly valuable in repairing and protecting concrete surfaces. Sodium silicate is an important ingredient in detergents and soaps. It acts as a builder, enhancing the effectiveness of surfactants by softening water and preventing the formation of insoluble soap scum. This improves the cleaning efficiency of household and industrial cleaning products. In the ceramic industry, sodium silicate is used as a dispersant in clay bodies, improving the flow and workability of ceramic materials. In glass manufacturing, it is used as a flux, lowering the melting temperature of silica and facilitating the production of various glass products.

Sodium silicate is used in water treatment processes. It helps remove impurities from water by enhancing the coagulation and flocculation processes. Sodium silicate helps form larger flocs from suspended particles, which can then be easily removed by sedimentation or filtration. In industrial water systems, sodium silicate is used as a corrosion inhibitor. It forms a protective layer on metal surfaces, reducing the rate of corrosion and extending the service life of equipment.

Sodium silicate-based products are used in fire-resistant coatings and treatments for building materials. These coatings form a protective layer that can withstand high temperatures, enhancing the fire resistance of structures and materials.

In the textile industry, sodium silicate is used in dyeing and printing processes. It acts as a mordant, helping to fix dyes to fabrics and improve color fastness. Sodium silicate is used as a flotation agent in the mining industry, helping to separate valuable minerals from ores.

Handling sodium silicate requires proper safety measures, using gloves, goggles, and protective clothing, and avoiding direct contact with the compound. Inhalation of dust or vapors should be avoided, and work areas should be well ventilated. Store sodium silicate in sealed containers in a cool, dry place to prevent moisture absorption and chemical degradation.

The environmental impact of sodium silicate is generally manageable. The compound is not biodegradable, but is inert in the environment. It should be used and disposed of in accordance with environmental regulations to minimize potential impacts to aquatic systems and soil. Proper handling and disposal methods can help mitigate any environmental risks associated with sodium silicate.

References

2003. Silica-alginate composites for microencapsulation. Applied Microbiology and Biotechnology, 61(5-6).
DOI: 10.1007/s00253-003-1308-5

2015. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer. International Journal of Molecular Sciences, 16(5).
DOI: 10.3390/ijms160511629

2024. Synthesis, Characterization, and Antibacterial Studies of Nickel-Silica Nanoparticles. Chemistry Africa, 7(12).
DOI: 10.1007/s42250-024-01153-4