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Chemical Name: Sodium Fluorosilicate
Common Names: Disodium hexafluorosilicate, Sodium silicofluoride
Chemical Formula: Na2SiF6
Appearance: White, odorless, crystalline powder
CAS Number: 16893-85-9
Main Hazards: Toxic if swallowed or inhaled, causes serious eye irritation, may lead to skin irritation. Prolonged or repeated exposure may affect bones and teeth due to fluoride toxicity. The dust can be severely irritating to the respiratory system.
Routes of Exposure: Inhalation, ingestion, dermal contact, eye exposure
Classification: Acute toxicity (oral and inhalation), Skin irritation, Eye irritation
Component: Sodium Fluorosilicate
Concentration: Typically over 99%
Relevant Impurities: May contain traces of sodium fluoride or silica
Inhalation: Move person to fresh air immediately. Loosen any tight clothing. If breathing becomes uncomfortable, seek medical attention quickly.
Skin Contact: Remove contaminated clothing. Wash skin thoroughly with water and soap. Seek attention if irritation persists.
Eye Contact: Rinse eyes with plenty of water for several minutes. Remove contact lenses if present and possible. Get medical advice.
Ingestion: Rinse mouth and drink water. Do not induce vomiting. Seek prompt medical help as swallowing even small amounts can cause harm.
Suitable Extinguishing Media: Use water spray, dry chemical, carbon dioxide, or alcohol-resistant foam. Sodium Fluorosilicate itself does not burn, but hazardous fumes may develop if heated.
Hazardous Combustion Products: Hydrogen fluoride, silicon oxides, sodium oxides
Protective Equipment: Wear self-contained breathing apparatus and protective clothing. Keep run-off water from entering drains or watercourses.
Personal Precautions: Prevent dust formation. Ensure adequate ventilation. Use personal protective equipment including gloves, eye protection, and dust mask.
Environmental Precautions: Avoid discharge into drains, sewers, or waterways since fluoride compounds can harm aquatic life.
Spill Cleanup: Sweep up using non-sparking tools. Place material in appropriately labeled containers for proper disposal. Wash spill area thoroughly once material is removed.
Safe Handling: Work in well-ventilated areas. Avoid inhaling dust or allowing material to contact skin and eyes. Do not eat, drink, or smoke near the product.
Storage Conditions: Store in a cool, dry, well-ventilated place. Keep container tightly closed. Keep away from acids, bases, water, and foodstuffs. Always use containers made of compatible materials like high-density polyethylene or glass.
Occupational Exposure Limit: Depending on country and regulation, the threshold for fluoride compounds may range from 2.5 mg/m3 up to 5 mg/m3 TWA.
Engineering Controls: Use local exhaust ventilation to prevent dust buildup.
Personal Protective Equipment: Wear chemical-resistant gloves, safety goggles or face shields, dust mask or respirator approved for particulate and fluoride exposure, lab coat or protective clothing to cover skin.
Appearance: White, crystalline solid
Odor: None
Melting Point: Decomposes before melting, at about 500 °C
Boiling Point: Not applicable
Solubility in Water: Slightly soluble
Density: Around 2.68 g/cm3
pH (1% solution): Slightly acidic
Chemical Stability: Stable under normal storage and handling conditions.
Hazardous Reactions: Reacts with acids to release toxic and corrosive hydrogen fluoride gas.
Incompatible Materials: Acids, strong bases, water in large amounts
Decomposition Products: Hydrogen fluoride, silicon tetrafluoride, sodium oxides
Acute Effects: Ingestion or inhalation can cause nausea, vomiting, diarrhea, abdominal pain, convulsions, and systemic fluoride poisoning. Exposure to high levels can lead to life-threatening electrolyte imbalances.
Chronic Effects: Long-term exposure may cause bone changes (fluorosis), dental issues, and kidney damage.
Carcinogenicity: Current evidence does not classify sodium fluorosilicate as a human carcinogen. Chronic toxicity is the larger concern, particularly for workplace safety.
Most at Risk: Workers handling the raw chemical, communities near improper disposal sites, and anyone exposed to large amounts without proper controls.
Toxicity to Aquatic Life: Fluoride ions released by sodium fluorosilicate can harm aquatic species. Fish and invertebrates show reduced growth and reproduction at concentrations above 1 mg/L.
Degradability: Not easily biodegradable. Persists in water and soil if released.
Potential Accumulation: May accumulate in the environment, especially if repeatedly released in small quantities.
Safe Disposal: Treat as hazardous waste. Follow local environmental regulations. Incineration may not be suitable as toxic gases can form.
Containers: Rinse empty containers thoroughly before discarding. Dispose of rinse water as hazardous waste.
Precaution: Keep waste away from sewer systems and natural waterways.
UN Classification: Sodium Fluorosilicate often ships under UN2674, which identifies it as a hazardous substance.
Hazard Class: Typically Class 6.1 (toxic substances).
Packing Group: Group III (low danger, but still requires care)
Labeling: Packaging must clearly show toxic and environmental hazard symbols.
OSHA: Recognized as hazardous, subject to workplace right-to-know rules.
EPA: Sodium fluorosilicate appears on several hazardous chemical lists. Disposal and emissions regulated in the United States.
REACH (Europe): Registration and proper use required. Limits set for workplace exposure.
Global: Use and movement controlled under GHS (Globally Harmonized System) guidelines to prevent misuse and minimize exposure risks.
