Sodium Sulphate Overview

Sodium sulphate commonly known as Glauber’s salt is considered as a major commodity chemical product. It was discovered by German-Dutch chemist Johann Rudolf Glauber in 1625. Glauber’s salt is the processed form of mineral mirabilite, a decahydrate sodium sulfate. The hygroscopic nature of sodium sulfate causes it to absorb water and moisture, forming Glauber’s salt. It exists as a natural resource and is found in the bed of lakes such as in Saskatchewan. Sodium sulphate is manufactured as a byproduct from the manufacture of viscose rayon fiber and byproduct from the manufacture of Methionine.
 

Properties of Sodium Sulphate

  • Sodium sulphate is the sodium salt of sulphuric acid with white crystalline solid appearance.
  • Sodium sulfate is chemically very stable compound.
  • Sodium sulphate being unreactive towards most of the oxidizing and reducing agents at normal temperatures.

Production of Sodium Sulphate

Sodium sulphate is commercially prepared by Mannheim process and Hargreaves process with an important reactant of sodium chloride and resulting sodium sulfate from these processes is known as salt cake. About two thirds of the production is from the matural mineral form called Mirabilite.

  • Mannheim and Hargreaves process

    • Sodium sulphate is produced from the sodium chloride (salt) and sulphuric acid in the manheim process. The resulting sodium sulfate from the manheim process is known as salt cake.
    2 NaCl + H2SO4 → 2 HCl + Na2SO4
    In the Hargreaves process, sodium sulphate is manufactured from the misture of sodium chloride, sulphur dioxide and water.
    4 NaCl + 2 SO2 + O2 + 2 H2O → 4 HCl + 2 Na2SO4

  • Viscous Rayon process

    • It is one of the major process for the large scale production of Gaubler salt by the mixture of sulphuric acid is neutralised by sodium hydroxide .
    2 NaOH(aq) + H2SO4(aq) → Na2SO4(aq) + 2 H2O(l)
    2NaHCO3 + MgSO4 → Na2SO4 + Mg(OH)2 + 2CO2

  • Paper Industry

    • Sodium sulphate is majorly utilized in the Kraft process of wood pulp. Sodium sulphate is used to remove non cellulose parts of the wood in the paper making process.
     

  • Glass Industry

    • Sodium sulphte is significantly used in the glass industry as a fining agent. Sodium sulphate is used to help remove small air bubbles from molten glass, glaze of glass and prevents scum formation of the glass melt during refining.
     

  • Textile Industry

    • Sodium sulphate is used in the manufacture of textile industry and helps in reducing negative charges so that the dyes can penetrate evenly.
     

  • Detergent Industry

    • Anhydrous sodium sulphate is contributed as a filler in powder products such as in home laundry products.
     

  • Other Applications

    • Anhydrous sodium sulphate is used as an inert drying agent for removing traces of water from organic solutions. Sodium sulphate is used as an effective laxative for the removal of certain drugs such as paracetamol from the over dosage.It is even used in thermal storage and heat storage in passive solar heating systems because of its high degree of crystallization and solubility properties.
     

PRODUCT IDENTIFICATION
CAS NO. : 7757-82-6, 7727-73-3
EINECS NO. : 231-820-9
FORMULA : Na2SO4
MOL WT. : 1030 – 1130
SYNONYMS : sodium sulphate, disodium sulphate, bisodium sulphate, kemol, sulfuric acid disodium salt, salt cake, thenardite, sodium sulphate anhydrous

PHYSICAL AND CHEMICAL PROPERTIES
PHYSICAL STATE : Hygroscopic white powder, Odorless
MELTING POINT : 880 – 888 C
BOILING POINT : 1100 C (Decomposes)
SPECIFIC GRAVITY : 2.66 – 2.75
SOLUBILITY IN WATER : Soluble
pH : Aqueous solution is neutral
NFPA RATINGS : Health: 1; Flammability: 0; Reactivity: 0
STABILITY : Stable under ordinary conditions

SALES SPECIFICATION
APPEARANCE : white powder
Na2SO4 : 99.0% min
WATER INSOLUBLES : 0.05% max
Mg : 0.15% max
Cl : 0.35% max
Fe : 0.002% max
pH : Neutral to slightly alkaline
MOISTURE : 0.2% max
WHITENESS   80% min
PARTICLE SIZE   50% (100 mesh)

TRANSPORTATION
PACKING : 25kgs, 50kgs, 1mt in Bag
HAZARD CLASS : Not regulated

OTHER INFORMATION

Sulphate (also spelled sulfate in USA) is any chemical compound containing the SO42- ion related to sulfuric acid (H2SO4). sulphates are salts or esters of sulfuric acid, formed by replacing one or both of the hydrogens with a metal or a radical as in sodium sulphate, Na2SO4. sulphates in which both hydrogens are replaced are called normal sulphates. Bisulphate is a compound that has the HSO4- radical. Bisulphate (called also hydrogen sulphate or acid sulphate) is a compound formed by replacing only one hydrogen in sulfuric acid. Sulfite (also sulphite) is a compound that contain the sulfite ion SO32-. Sulfites are salts or esters of sulfurous acid (H2SO3), formed by replacing one or both of the hydrogens with a metal or a radical as in sodium sulfite, Na2SO3. Sulfites in which both hydrogens are replaced are called normal sulfites. Bisulfite is a compound that has the HSO3- radical. Bisulphate (called also hydrogen sulfite or acid sulfite) is a compound formed by replacing only one hydrogen in sulfurous acid. The term of ‘meta’ or ‘pyro’ is the chemical prefix for oxo acid formed through the loss of one water molecule (dehydration) from two molecules of ortho acid by heating. Pyrosulfuric acid is an example ( 2H2SO4 – H2O = H2S2O7). Ortho acid is the compound fully hydrated acid or its salts. Orthophosphoric acid is an example (2.H3PO4 = P2O5.3H2O), in contrast to the less hydrated form, pyrophosphoric acid (2.HPO3 = P2O5.H2O). Na2O5S2 is called sodium metabisulfite (2.HNaO3S – H2O). Sulfide is a compound having one or more sulfur atoms in which the sulfur is connected directly to a carbon, metal, or other nonoxygen atom; for example sodium sulfide, Na2S. Sulfide ion is S2- with oxidation number -2. Bisulfide ion is an anion formed by two sulfur atoms having an overall -2 charge, (S2)2-. Sulfamate is a salt of sulfamic acid (HSO3NH2). Calcium sulfamate Ca(SO3NH2)2 is an example.