Descriptions of Sodium Sulfide

Sodium Sulfide is a vital inorganic chemical used across many industries for its strong alkaline and reducing properties. With the chemical formula Na₂S and its hydrated form Na₂S·9H₂O, it dissolves easily in water, forming clear, strongly alkaline solutions. Although sodium sulfide appears as a yellow solid, its solutions are colorless. One of its distinctive features is the emission of hydrogen sulfide (H₂S) gas, which has a pungent “rotten egg” odor when exposed to air.

Sodium sulfide also reacts with hydrogen peroxide to produce sodium sulfate, making it a versatile chemical in industrial processes.

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Properties of Sodium Sulfide

• Appearance: Yellow to red solid, depending on impurities

• Odor: Strong rotten egg smell due to H₂S

• Molecular Weight: 78.04 g/mol

• Melting Point: ~1,175°C (2,147°F)

• Solubility: Highly soluble in water, forming a strongly alkaline solution

• Hydrated Forms: Most commonly Na₂S·9H₂O, which is more stable and easier to handle

• Ionic Nature: Contains two sodium ions (Na⁺) and one sulfide ion (S²⁻)

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Applications of Sodium Sulfide

Sodium sulfide finds applications in a wide range of industries due to its chemical reactivity:

Pulp and Paper Industry

• Kraft Process: Breaks down lignin in wood, aiding cellulose fiber separation for paper production.

Textile Industry

• Dyeing and Bleaching: Functions as a reducing agent to fix dyes and remove excess color.

• Desulfurizing and Dechlorinating: Eliminates sulfur and chlorine compounds, improving fabric quality.

Leather Industry

• Tanning: Used to remove hair from hides and soften leather for processing.

Chemical Industry

• Production of Sulfur Compounds: Serves as a precursor for manufacturing sodium thiosulfate, sodium polysulfide, and other sulfur-containing chemicals.

• Reducing Agent: Commonly used in organic and inorganic reactions to donate electrons and reduce other substances.

• Na₂S is often used alongside other industrial chemicals, such as Caustic Soda Flakes, to enhance chemical processes in pulp, textile, and chemical manufacturing.

Water Treatment

• Wastewater Treatment: Helps precipitate heavy metals, making industrial effluents safer to release.

Mining Industry

• Ore Flotation: Assists in separating valuable minerals by altering the surface properties of ores.

Rubber Industry

• Vulcanization: Improves the elasticity and strength of rubber products.

Oil & Gas Industry

• Desulfurization: Removes sulfur compounds from petroleum and gas, improving fuel quality and reducing emissions.

Photographic Industry

• Film Development: Acts as a fixing agent to dissolve unexposed silver halide crystals in films and papers.

Electronics & Batteries

• Sodium-Sulfur Batteries: Used as an electrolyte, providing high energy efficiency.

Agriculture

• Pesticides and Fungicides: Used in formulations to control pests and fungal infections.

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Safety, Handling, and Storage

Handling sodium sulfide requires caution due to its toxicity and corrosiveness:

• Toxicity: Can irritate skin, eyes, and the respiratory system. Contact with acids releases poisonous H₂S gas.

• Corrosiveness: Can damage metals and other materials.

• Storage: Store in a cool, dry, well-ventilated area, away from acids and moisture. Proper ventilation is essential to prevent gas accumulation.

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Packing and Transportation

• Forms: Crystallized, broken, or prilled

• Packaging: Polyethylene bags, fiber drums, or IBC containers

• Container Loading: Sodium sulfide is typically loaded into 20–25 MT containers, ensuring proper stacking and protection from moisture. Ventilation during transport is important to prevent hydrogen sulfide buildup.

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Environmental Considerations

• Aquatic Toxicity: Harmful to aquatic life; effluents must be treated before release.

• Biodegradability: Can naturally decompose, but high concentrations can cause ecological damage.

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Technical Data Sheets of Sodium Sulfide