Introduction

Sodium sulfide, or Na₂S, is an inorganic compound with several applications. It is highly reactive and a very important commodity chemical used in the manufacture of chemicals, textiles, and paper, among other industries.

What is Sodium Sulfide?

Na₂S is a yellowish to reddish crystalline solid that dissolves readily in water, forming a strongly alkaline solution. It belongs to the class of reducing agents and can be used in either anhydrous or hydrated forms, depending on specific industrial requirements. One notable characteristic is its distinctive odor, caused by the release of hydrogen sulfide gas when it comes into contact with moisture.

Industrially, the value of this compound lies in its reducing and purifying properties. It finds indispensable applications in various processes, both in technical and pure forms, where reliable performance is required.

Properties of Sodium Sulfide

• Chemical Formula: Na₂S
• Molecular Weight: 78.04 g/mol (anhydrous form)
• Appearance: Yellow to red flakes or granules, varying with impurities and hydration level
• Solubility: Highly soluble in water, producing a strongly alkaline solution
• Odor: Characterized by a pungent smell due to hydrogen sulfide gas
• Reactivity: Reacts with acids to produce hydrogen sulfide gas and with oxidizing agents and atmospheric moisture

Applications and Uses

Na₂S is a crucial compound with unique properties that make it indispensable in many industries. Below are its key applications:

1. Pulp and Paper Industry

• It is an essential chemical used in the Kraft process, dissolving the lignin natural binder in wood- and enabling cellulose fibers to be separated for the production of high-quality papers, which makes it indispensable in modern paper manufacture.

2. Water Treatment

• The compound prevents corrosion in the water systems by scavenging dissolved oxygen. It is also used to remove heavy metals from wastewater by precipitating them as insoluble sulfides, thus ensuring safer treated water.

3. Textile Industry

• Sodium sulfide, as a degumming and desulfurization reagent, prepares the fabrics by bleaching off colors and sulfur impurities. Moreover, it acts to neutralize chlorine-based bleaching agents to give good fabric quality with less environmental harm.

4. Leather Industry

• In leather processing, it is crucial for the liming process, breaking down proteins, and removing hair from hides. This ensures soft and fine leather suitable for various applications.

5. Chemical Manufacturing

• The compound is widely used in producing rubber chemicals and sulfur dyes, enhancing elasticity in rubber products and providing durable, colorfast dyes for textiles and other materials.

6. Additional Applications

• It is also used in mineral flotation, besides mining, improving the oil flow in petroleum extraction, and aiding the production of dyes, and detergents. The versatile nature of this product allows it to be useful for many processes.

Various Grades

Na₂S is produced and supplied in different grades, tailored to meet diverse industrial needs. These grades vary in purity, physical form, and composition, ensuring compatibility with specific applications.

1. Flake Sodium Sulfide

• This is generally used in higher-purity grades, like 60-70% concentration, in paper manufacture, water treatment, and leather. Its consistency and ease of handling make the product ideal for large-scale applications.

2. Granular Sodium Sulfide

• It has an improved flowability and low dust grade, which is especially suitable for automated processes in mining and oil recovery industries where efficiency and safety are of utmost importance.

3. Low-Iron Sodium Sulfide

• Containing minimal iron content, this grade is essential for applications requiring high purity, such as dye and pigment production. It ensures product quality by avoiding contamination.

4. Technical Grade

• This economical option is ideal for general industrial use, including mineral flotation and crude oil recovery, where ultra-high purity is unnecessary.

5. Sodium Sulfide Solution

• Aqueous solutions are offered in various concentrations for applications needing a ready-to-use form, such as water treatment and certain chemical manufacturing processes.

Production Process

Na₂S is industrially produced through the reduction of sodium sulfate (Na₂SO₄) with a carbon source like coal or coke at high temperatures (1000–1200°C), yielding sodium sulfide and carbon dioxide:

Na₂SO₄ + 2C → Na₂S + 2CO₂

An alternative method involves reacting sodium hydroxide (NaOH) with hydrogen sulfide (H₂S):

2NaOH + H₂S → Na₂S + 2H₂O

These methods ensure a steady supply for industries requiring this essential chemical.

Packaging and Storage

It ensures the stability and safety of Na₂S. This is usually in polyethylene-lined woven bags or steel drums with capacities from 25 kg to 1,000 kg. The product must be properly labeled with a correct identification number, with adherence to transportation regulations, for example, UN No. 1849. The product should be stored in a cool, dry, well-ventilated area away from moisture.

Safety Considerations

Handling this compound requires strict safety measures:

• Personal Protective Equipment (PPE): Use gloves, goggles, and respiratory protection.
• Ventilation: Ensure adequate ventilation to prevent the buildup of hydrogen sulfide gas.
• Emergency Measures: In case of contact with skin or eyes, rinse thoroughly with water and seek medical attention.

Due to its reactive nature, adherence to safety protocols is crucial to minimize risks.

Conclusion

Na₂S is an essential compound in various industries, including chemicals, textiles, and leather processing. Its unique properties and versatility make it indispensable for many applications. However, proper handling and safety measures are vital due to its hazardous nature. To source high-quality Na₂S tailored to your needs, consider partnering with ZÜMRÜT International Kimya Co., a globally trusted supplier of chemical products.

TECHNICAL DATASHEET

SPECIFICATIONS	RESULTS
Appearance	Yellow Flakes
Na2S, %	60 ± 2
Na2SO3, %	< 2
Na2CO3, %	< 0.5
Fe, ppm	< 10
Insoluble Content, %	< 12
Density, g/ cmᵌ	1600
Melting Point, ℃	92

 

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