1. Production Methods
Sodium bromate is primarily produced through chlorine oxidation and electrolysis methods:
- Chlorine Oxidation Method:
- Bromination of Lime Slurry: Bromine is added to a lime (Ca(OH)₂) slurry, forming bromate and bromide mixtures.
- Chlorine Oxidation: Chlorine gas is introduced to oxidize bromide to bromate, forming bromate-calcium solution.
- Barium Precipitation: The solution is treated with barium chloride (BaCl₂) to form barium bromate (Ba(BrO₃)₂), which is then filtered and washed.
- Sodium Carbonate Exchange: The barium bromate reacts with sodium carbonate (Na₂CO₃) to yield sodium bromate and insoluble barium carbonate (BaCO₃).
- Crystallization & Drying: The solution is evaporated, crystallized, and dried to obtain pure NaBrO₃.
- Electrolysis Method:
- A bromide (NaBr) solution is electrolyzed, where bromide ions (Br⁻) are oxidized at the anode to form bromate (BrO₃⁻).
- The solution is then concentrated and crystallized to obtain NaBrO₃.
2. Key Safety Precautions
Sodium bromate is a strong oxidizer and poses significant hazards:
- Storage & Handling:
- Store in cool, dry, and well-ventilated areas (<30°C), away from flammables, reductants (e.g., sulfur, metals, organic compounds).
- Use non-reactive containers (e.g., polyethylene-lined steel drums) to prevent corrosion.
- Reactivity Risks:
- Explosive when mixed with sulfides, phosphorus, aluminum, or sulfuric acid.
- Decomposes at 381°C, releasing oxygen, which can intensify fires.
- Personal Protection:
- Use gloves, goggles, and respirators to avoid inhalation or skin contact.
- In case of exposure, flush with water for 20 minutes and seek medical help.
- Fire & Spill Response:
- Use sand, dry lime, or CO₂ extinguishers (avoid water jets, as it may spread contamination).
- For spills, contain and collect using non-combustible materials.
3. Industrial & Laboratory Uses
- Oxidizing agent in gold extraction (with NaBr).
- Textile industry (wool treatment, dye oxidation).
- Analytical chemistry (phenol determination).
- Historically in cosmetics (cold-wave perms, now restricted due to toxicity).
4. Environmental & Regulatory Concerns
- Classified as a Group 2B carcinogen (IARC).
- Banned in food additives (e.g., flour treatment) in many countries.
For detailed handling protocols, refer to Material Safety Data Sheets (MSDS)
