Caustic Soda (Sodium Hydroxide)

Overview

Caustic Soda (Sodium Hydroxide, CAS No: 1310-73-2) is a strong alkaline chemical widely used in various industrial applications. It is found in white, hygroscopic solid form and has high solubility in water.

Caustic soda is available in pellet, flake, or solution forms. It is used in industrial cleaning products, pulp production, textile processing, water treatment, and the production of many chemicals. It is an extremely corrosive substance and should be used with appropriate safety precautions.

Applications

Caustic Soda has a wide range of industrial and commercial applications:

Technical Specifications

Safety Information

Hazard Symbols and Statements

Corrosive Serious Burn Hazard Environmental Hazard

Personal Protective Equipment (PPE)

• Acid and alkali resistant gloves (nitrile or neoprene)
• Face shield or chemical goggles
• Acid/alkali resistant apron
• Respiratory protection against dust (in powder form)
• Closed shoes against chemical contamination risk

Storage Conditions

• Store in a cool, dry, well-ventilated area
• Protect from atmospheric moisture and carbon dioxide
• Keep away from acids and water-reactive substances
• Keep in original packaging, tightly closed
• Storage temperature: 15-30°C

Fire Fighting

• Caustic soda is not flammable but may cause fire when in contact with flammable materials
• Suitable extinguishers: Dry chemical, CO₂
• Do not use water (risk of exothermic reaction)
• Firefighting personnel should use full protective equipment

Handling and Storage

Transportation

• Ensure containers are tightly closed
• Protect from acids and moisture
• Provide adequate ventilation in transport vehicles
• Keep neutralizing material (weak acid) available in case of spills
• Use corrosive substance labels during transport

Storage

• Store in stainless steel, polyethylene, or specially coated containers
• Display appropriate signs in storage areas
• Keep acid neutralizing material in storage areas
• Provide secondary containment for large quantities
• Storage shelves should be made of corrosion-resistant material

Spill Response Measures

• Evacuate exposed personnel from the area
• Use appropriate personal protective equipment
• Clean up dust without dispersing into the air
• Neutralize with a weak acid (vinegar or dilute hydrochloric acid)
• Rinse the area with plenty of water (after neutralization)
• Dispose of spillage using appropriate waste disposal methods

Regulatory Information

GHS Classification

• Skin Corrosion/Irritation Category 1A
• Serious Eye Damage/Eye Irritation Category 1
• Acute Toxicity (Oral) Category 4

Important Regulations

• REACH: Registered
• CLP: Compliant
• FDA: Approved for use in food processing (21 CFR 184.1763)
• EPA: Registered

Industrial Standards

• ISO 9001:2015 certified production
• FCC compliant for food-grade versions
• OEKO-TEX compliant for textile-grade versions

Environmental Information

Environmental Impact

Caustic soda can cause harmful effects in aquatic environments by raising pH. It is toxic to aquatic life at high concentrations. Can be neutralized in soil to become harmless.

Biodegradability

• Not biodegradable
• Not persistent in the environment (neutralized)
• Rapidly dilutes and neutralizes in soil and water

Waste Management

• Classified as hazardous waste
• Can be disposed of by neutralization at licensed waste disposal facilities
• Should not be discharged into sewers or surface waters
• Dispose of in accordance with local regulations
• Waste caustic soda solutions should be neutralized before disposal

Frequently Asked Questions

What safety precautions should I take when working with caustic soda?

When working with caustic soda, always use appropriate personal protective equipment (gloves, goggles, apron). Work in well-ventilated areas. In case of skin or eye contact, rinse immediately with plenty of water and seek medical attention. Keep neutralizing solution (weak acid) in the work area.

What should be considered when preparing caustic soda solution?

When preparing caustic soda solution, ALWAYS add caustic soda to water, NEVER add water to caustic soda. Due to exothermic reaction, water may boil and splash. Add slowly and stir. Use plastic or stainless steel containers. Glass containers are not suitable for long-term storage.

What is the difference between caustic soda and sodium carbonate (washing soda)?

Caustic soda (NaOH) is a strong base with pH close to 14. Sodium carbonate (Na₂CO₃) is a weaker base with pH around 11. Caustic soda causes serious burns on skin, while sodium carbonate causes milder irritation. In industrial applications, caustic soda is preferred as a stronger source of alkalinity.

How should caustic soda be stored?

Caustic soda should be stored in tightly closed, moisture-proof containers as it absorbs atmospheric moisture and carbon dioxide. Plastic containers or specially coated metal containers are ideal. Store in a cool, dry, well-ventilated area, away from acids and water-reactive substances.

What should I do in case of a caustic soda spill?

For small spills, neutralize with a weak acid solution (vinegar or dilute hydrochloric acid) and rinse with plenty of water. For large spills, evacuate the area, wear appropriate PPE, and call professional cleaning teams. If in powder form, sweep without dispersing dust into the air. Dispose of waste properly after neutralization.