What is Sodium Sulphide

Sodium Sulphide Product

Sodium sulfide is a yellow, solid flake. It is used in the pulp and paper industry and in leather processing to remove hair from hides. Sodium sulfide may be used in the making of colors and dyes. It can also be used in the manufacture of other chemicals, metals or in mining  and in waste water, soil and process sludge treatment.

Manufacturing Process

Synthesis Process: Industrially, sodium sulfide is produced by passing sodium sulfate through carbon and sodium sulfate is reduced in the process. This method ensures that the product, sodium sulfide is free from iron and water. The reduced sodium sulfide is then heated in methanol to remove the impurities. After which, it is filtered to remove the ethanol. Another way to manufacture sodium sulfide is by reacting sodium hydroxide with hydrogen sulfide. However, in the process of passing hydrogen sulfide gas through sodium hydroxide liquid, impurities may be interfere or incorporated into the final product. The presence of impurities may cause a great different in the appearance in sodium sulfide as they have highly coloured nature due to the passing of hydrogen sulfide gas.

Sodium Sulphide Applications

Sodium sulphide adopts an anti-fluoride structure, where the smaller sodium ions occupy the larger sulphide ions holes in a crystal lattice and vice versa. It can also be oxidized when heated to yield sodium carbonate and sulphur dioxide. When exposed to air, sodium sulphide smells like rotten egg and this is due to the releases of hydrogen sulphide gas. In addition, sodium sulphide can be treated with sulphur to yield polysulfide.

Textile Industry
Sodium sulfide is used in textile dyeing and finishing. It can be used as a bleaching agent, serving as an alternative to sodium chlorite and hydrogen peroxide. It removes yellowish stains and spots that are not removed by laundering process. Sodium sulfide can also be used as a desulfurizing and a dechlorinating agent when dealing with leather materials. In addition, it is used to obtain sulfur black dyes, which can in turn be treated and processed to obtain other color dyes.

Paper Industry
It is primarily used in pulp and paper industry in the Kraft process of manufacturing paper. It is a component of white liquor in addition to sodium hydroxide, and white liquor plays an important role in manufacturing wood pulp. It is involved in the first stage of the Kraft process or the impregnation step where the wood chips are impregnated with the white liquor.

Other Applications

Sodium sulfide can also be used in the manufacture of other chemicals, metals or in mining processes and in waste water, soil and process sludge treatment.

Textile Industry


Paper Industry


Waste Water Treatment


Molecular Weight78.05 g/mol (anhydrous)
Melting Point1176°C
CAS No.1313-82-2 (anhydrous)
OdourRotten egg smell when exposed to moisture in air.
Density1.856 g/cm3
Solubility20oC 18.6 g/100 mL