Barium Hydroxide: Properties, Production and Industrial Applications

Barium hydroxide (Ba(OH)₂) is an important alkaline earth metal hydroxide with significant industrial applications. This white crystalline compound exists in both anhydrous and octahydrate forms, serving as a versatile chemical reagent across multiple industries while requiring careful handling due to its moderate toxicity.

Physical and Chemical Properties

Basic Characteristics

• Chemical formula: Ba(OH)₂ (anhydrous), Ba(OH)₂·8H₂O (octahydrate)

• Molar mass: 171.34 g/mol (anhydrous), 315.46 g/mol (octahydrate)

• Appearance: White powder (anhydrous), colorless crystals (octahydrate)

• Density: 3.74 g/cm³ (anhydrous), 2.18 g/cm³ (octahydrate)

Thermal Properties

• Melting point: 408°C (anhydrous), 78°C (octahydrate loses water)

• Decomposition: Begins at 800°C forming BaO

Solubility Characteristics

• Water solubility:

  • 3.89 g/100 mL (20°C, anhydrous)

  • 56 g/100 mL (15°C, octahydrate)

• Solubility in other solvents:

  • Soluble in methanol (1.5 g/100 mL)

  • Insoluble in acetone and ether

Chemical Reactivity

• Basicity: Strong base (pH ~11-12 in 0.1M solution)

• CO₂ absorption: Reacts with atmospheric CO₂ to form BaCO₃

• Neutralization: Reacts vigorously with acids

Industrial Production Methods

1. From Barium Sulfide

The primary commercial production method:
BaS + 2H₂O → Ba(OH)₂ + H₂S

2. From Barium Oxide

Hydration process:
BaO + H₂O → Ba(OH)₂

3. Laboratory Preparation

Precipitation from barium chloride:
BaCl₂ + 2NaOH → Ba(OH)₂ + 2NaCl

Industrial and Commercial Applications

1. Petroleum Industry (40% of consumption)

• Drilling fluid additive: Controls pH and removes sulfates

• Grease manufacture: Thickening agent in high-temperature greases

• Oil refining: Catalyst in certain processes

2. Chemical Manufacturing

• Precursor for other barium compounds:

  • Barium stearate (lubricants)

  • Barium titanate (electronics)

  • Barium peroxide (pyrotechnics)

• Catalyst in organic synthesis:

  • Aldol condensations

  • Ester hydrolysis

3. Sugar and Sweetener Processing

• Purification agent: Removes sulfates and phosphates

• Decolorization: Helps produce white sugar

• Byproduct recovery: From molasses processing

4. Lubricant Additives

• Extreme pressure additive: In industrial lubricants

• Corrosion inhibitor: For metal surfaces

5. Other Specialized Uses

• Glass manufacturing: Modifies optical properties

• Rubber vulcanization: Accelerator additive

• Water treatment: Heavy metal removal

Safety and Handling Protocols

Toxicity Profile

• Oral LD₅₀ (rat): 250-500 mg/kg

• Inhalation risk: Moderate (dust irritation)

• Skin corrosion: Category 1B

Exposure Control Measures

• Engineering controls: Local exhaust ventilation

• PPE requirements:

  • Chemical-resistant gloves (neoprene/nitrile)

  • Dust respirator (N95 minimum)

  • Protective eyewear with side shields

Storage and Handling

• Storage conditions: Airtight containers in dry area

• Incompatibilities: Acids, CO₂, moisture

• Shelf life: 1-2 years if properly stored

Market and Economic Data

Global Production

• Estimated annual production: 50,000-75,000 metric tons

• Major producers: China, Germany, India

Pricing Structure

• Industrial grade: $800-1,200/ton

• High purity (>98%): $1,500-2,000/ton

• Laboratory grade: $50-100/kg

Environmental Considerations

Ecological Impact

• Aquatic toxicity: LC₅₀ (fish) 10-50 mg/L

• Soil mobility: Medium (Koc ~200)

Regulatory Status

• Listed on REACH Annex XIV

• Classified as Acute Tox. 4 (H302)

• OSHA PEL: 0.5 mg/m³ (as Ba)

Emerging Applications and Research

Advanced Materials

• Nanoscale barium hydroxide for catalysis

• Precursor for superconducting materials

Environmental Technologies

• CO₂ capture applications

• Flue gas desulfurization enhancement

Conclusion

Barium hydroxide remains a critical industrial chemical despite its toxicity concerns, valued for its strong basicity and unique reactivity. While its use in petroleum and chemical industries dominates current applications, emerging technologies in materials science and environmental applications may expand its utilization. Strict adherence to safety protocols and proper handling procedures can effectively mitigate the health and environmental risks associated with this versatile but potentially hazardous compound.