50% Caustic Soda Solution
Concentrated sodium hydroxide solution for industrial cleaning, paper production, textile processing, petroleum refining and chemical manufacturing
Overview
50% Caustic Soda (Sodium Hydroxide, CAS No: 1310-73-2) is a powerful alkaline chemical presented as a 50% aqueous solution. This solution, widely used in industrial applications, is known for its high reactivity and effective cleaning properties.
Caustic soda solution is hygroscopic and can absorb carbon dioxide from the air, converting to sodium carbonate. It must therefore be properly stored and handled. It can react with most materials except certain metals, glass, ceramics, and some plastics.
Applications
50% Caustic Soda solution has numerous industrial and commercial applications:
Chemical Industry
Used in the synthesis of organic and inorganic chemicals, soap production, and various chemical reactions.
Pulp and Paper
Used to separate lignin and other impurities from pulp. Plays a key role in paper bleaching processes.
Textile Industry
Used in mercerization of cotton fabrics, dye removal processes, and fiber treatment.
Petroleum Refining
Used in crude oil and natural gas processing for acid neutralization and various purification processes.
Cleaning Products
Active ingredient in industrial cleaning agents, drain and oven cleaners.
Water Treatment
Used as pH regulator in water and wastewater treatment plants, and for heavy metal precipitation.
Technical Specifications
| Property | Value | Unit | Test Method |
|---|---|---|---|
| Chemical Formula | NaOH | - | - |
| CAS Number | 1310-73-2 | - | - |
| EC Number | 215-185-5 | - | - |
| Molecular Weight | 40.00 | g/mol | - |
| Appearance | Clear, colorless liquid | - | Visual |
| Odor | Odorless | - | - |
| Density (20°C) | 1.52-1.53 | g/cm³ | ASTM D4052 |
| pH Value | >14 | - | ASTM E70 |
| Freezing Point | 12 | °C | ASTM D1015 |
| Boiling Point | 140 | °C | ASTM D1078 |
| NaOH Content | 50±1 | % | ASTM E291 |
| Sodium Carbonate (Na₂CO₃) | ≤0.5 | % | ASTM E291 |
| Sodium Chloride (NaCl) | ≤0.05 | % | ASTM E291 |
| Iron (Fe) | ≤10 | ppm | ASTM E394 |
| Heavy Metal Content (Pb) | ≤5 | ppm | USP |
Safety Information
Hazard Symbols and Statements
Corrosive Serious Burn Hazard Environmental Hazard
Personal Protective Equipment (PPE)
- Chemical-resistant gloves (nitrile or neoprene)
- Face shield or safety goggles
- Acid/base resistant apron
- Respiratory protection (in case of dust or vapor formation)
- Chemical-resistant shoes or boots
Storage Conditions
- Store in a cool, dry, and well-ventilated area
- Maintain in stainless steel, polyethylene, or specially coated tanks
- Keep away from acids and flammable materials
- Storage temperature: 15-30°C (protect from freezing)
- Protect from moisture and air exposure
Fire Fighting
- Suitable extinguishers: Dry chemical, CO₂, sand
- Do not use water (may react)
- In case of fire, toxic fumes (sodium oxide) may be released
- Firefighting personnel should wear full protective equipment
Handling and Storage
Transportation
- Ensure containers are tightly closed
- Transport separately from acids and flammable materials
- Use stainless steel or polyethylene tankers
- Have neutralizing material (weak acid) available for spills
- Provide adequate ventilation in transport vehicles
Storage
- Store in stainless steel, polyethylene, or specially coated tanks
- Display appropriate signage and spill kit in storage area
- Storage tanks should have heating system (to prevent freezing)
- Provide secondary containment for large volumes
- Maintain acid neutralizing material in storage areas
Spill Response Measures
- Evacuate exposed personnel from area
- Use appropriate personal protective equipment
- Neutralize spill with weak acid (vinegar, citric acid solution)
- Wash neutralized waste with plenty of water
- For large spills, call professional cleanup team
Regulatory Information
GHS Classification
- Skin Corrosion/Irritation Category 1A
- Serious Eye Damage/Eye Irritation Category 1
- Acute Toxicity (Oral) Category 4
- Acute Aquatic Hazard Category 1
Important Regulations
- REACH: Registered
- CLP: Compliant
- ADR: Class 8 Corrosive Substance
- IMDG: Class 8 Corrosive Substance
- IATA: Class 8 Corrosive Substance
Industry Standards
- ISO 9001:2015 Quality Management System
- ISO 14001:2015 Environmental Management System
- OHSAS 18001: Occupational Health and Safety Management
- GMP+ for Industrial Applications
Environmental Information
Environmental Impact
Caustic soda solution can create high pH in aquatic environments, causing significant damage. It is lethal to aquatic life at high concentrations. If not neutralized, it negatively affects plant life in soil.
Biodegradation
- Water: Quickly dilutes and neutralizes
- Soil: Reacts with acidic soils and neutralizes
- Not biodegradable, must be chemically neutralized
Waste Management
- Classified as hazardous waste
- Can be disposed in licensed waste facilities by neutralization with acids
- Do not discharge to sewers or surface waters
- Dispose in accordance with local environmental regulations
- For large quantities, work with professional waste management companies
Frequently Asked Questions
How to dilute 50% caustic soda solution?
When diluting caustic soda, ALWAYS add caustic soda to water, NEVER add water to caustic soda. Add slowly while stirring and avoid excessive heating of the solution. Use appropriate personal protective equipment and work in well-ventilated area.
Which materials are compatible with caustic soda solution?
Suitable materials for 50% caustic soda solution: Stainless steel (316L), polyethylene (HDPE, LDPE), polypropylene, PTFE (Teflon), PVDF, and rubber coatings. Not compatible with metals like aluminum, zinc, tin, and copper.
What to do if caustic soda contacts skin?
Immediately rinse with plenty of water for at least 15 minutes. Remove contaminated clothing. Seek medical attention. Do not use acid to neutralize. In case of eye contact, rinse eyes with water for at least 15 minutes and consult ophthalmologist immediately.
What to do if caustic soda solution freezes?
Slowly bring frozen caustic soda solution to room temperature (do not use heater). Ensure it is completely dissolved and homogeneous. Freeze-thaw cycles may affect concentration, so test before use.
What is the shelf life of caustic soda solution?
The shelf life of properly stored 50% caustic soda solution is typically 1 year. However, when exposed to air, it may convert to sodium carbonate. Analysis before use is recommended.