Sodium Carbonate

Its largest applications are in the manufacture of glass, paper, rayon, soaps and detergents. As a food additive, it is used as an acidity regulator, anti-caking agent, raising agent and stabiliser. As a medicine, because it neutralises gastric acid, it acts an antacid.

Synonyms
Soda ash, Soda crystals, Washing soda, calcined soda, E500
Chemical Formula
Na2CO3; Na₂CO3.10H2O
CAS Number
491-19-8 (anhydrous)

Characteristics

Molar Weight
105.988 g/mol (anhydrous); 285.99 g/mol (decahydrate)
Melting Point
851 °C
Density
2.54 g/cm³
Forms
Crystals, White

Uses and applications

Key applications

  • Food packaging
  • Cleaning products
  • Pulp and paper
  • Solvents
  • Personal care
  • Bleaching agent
  • Paint and Coatings

General Information about Sodium carbonate

Sodium carbonate is the sodium salt of carbonic acid and is one of the most important inorganic base chemicals in industry. In nature, it occurs as a hydrate in various forms and forms minerals such as trona, natrite or crystal soda. These occur mainly in alkaline salt lakes, desert regions or in former sea basins with high evaporation rates. Significant natural deposits are found in the USA, Egypt and other parts of Africa.
Properties of sodium carbonate
Sodium carbonate is a white, crystalline powder that forms a strongly alkaline solution in water when heated. It reacts with acids to form carbon dioxide and, due to its basicity, has a neutralising and fat-dissolving effect.
When exposed to air, it absorbs moisture and carbon dioxide and converts to sodium hydrogen carbonate. Depending on pressure and temperature, it crystallises in various modifications, which may be anhydrous or hydrated.
Sodium carbonate is mainly produced using the Solvay process. This involves introducing ammonia and carbon dioxide into a saturated sodium chloride solution. The sodium hydrogen carbonate formed is then calcined (heated).
The Solvay process is a closed cycle in which ammonia and carbon dioxide are recovered. This makes production economical and environmentally friendly compared to older processes such as the Leblanc process.
In some regions, particularly in the USA, sodium carbonate is also extracted from the mineral trona. It can also be produced on a smaller scale by electrolysis of sodium chloride and subsequent reaction of sodium hydroxide with CO2.

Sodium carbonate in the glass industry

Sodium carbonate is a key fluxing agent in glass manufacturing. It lowers the melting point of silicon dioxide, the main component of glass, saving energy and facilitating processing. It also reacts with silicon dioxide to form sodium silicate, which improves the viscosity and mouldability of the glass melt. It is used in:
  • Soda-lime glass (windows, bottles, containers)
  • Flat glass (mirrors, architectural glass)
  • Glazes and enamel

Sodium carbonate in the paper industry

In paper production, sodium carbonate serves as an alkali agent and pH regulator. It supports the dissolution of cellulose from wood fibres, aids in the bleaching process and contributes to the neutralisation of acidic residues. Its pH-regulating effect improves paper quality and durability.
Senior couple washing dishes

Sodium carbonate in the cleaning industry

Under the name washing soda, sodium carbonate is a key ingredient in many cleaning and washing products. It enhances the cleaning effect, dissolves grease and dirt particles, softens water and neutralises odours. Typical applications are:
  • Household cleaners: all-purpose, drain and carpet cleaners
  • Detergents: water softeners and cleaning enhancers
  • Industrial cleaners: grease removers and descalers
  • Air fresheners: neutralisation of organic odours
Its alkaline reactivity makes sodium carbonate a versatile and environmentally friendly cleaning aid.
Color lipstick palette, close-up brush. decorative cosmetics.

Sodium carbonate in the cosmetics industry

In the cosmetics industry, sodium carbonate is used as a pH regulator to ensure the stability of creams, shampoos and shower gels.
In exfoliants, it serves as a mild abrasive, and in toothpastes as a gentle polisher to remove plaque and discolouration. Its alkaline effect also helps to cleanse and clarify the skin.

Sodium carbonate in the food industry

Sodium carbonate (E 500) is a versatile additive in food processing. It serves as a raising agent, pH regulator and texture enhancer. Applications include:
  • Production of lemonades and carbonated drinks
  • Baked goods: ingredient in baking powder and pretzel lye
  • Snacks and confectionery: texture improvement and colour intensification
  • Beverages and sauces: regulation of acidity
  • Clarification and stabilisation: of fruit juices and wines
A female hand holds a package of yellow pills on the background of a heap of colored pills in packages

Sodium carbonate in the pharmaceutical industry

In the pharmaceutical industry, sodium carbonate is used as a pH regulator, solubiliser and disintegrant. It ensures stable pH values in injection solutions, eye drops and tablets.
In effervescent tablets, it reacts with acids to release carbon dioxide, which accelerates dissolution. As a component of antacids, it neutralises excess stomach acid. In equipment cleaning, it removes organic residues and fats.

Further applications of Sodium carbonate

Sodium carbonate in agriculture

In agriculture, sodium carbonate is used for soil deacidification and pH regulation. It also has a fungicidal effect and, in low concentrations, serves as a natural herbicide against moss and algae.
In animal feed - especially for ruminants - it stabilises digestion and prevents acidosis (hyperacidity). It is also used to clean stables, milking equipment and other apparatus.

Sodium carbonate in water treatment

In water treatment, sodium carbonate regulates the pH value and protects pipes from corrosion. It is used in drinking water systems, boilers, swimming pools and sewage treatment plants.
It also neutralises acidic waste water and binds heavy metals in industrial processes in the chemical, metal and food industries.

Sodium carbonate in the construction industry

Sodium carbonate has a wide range of applications in the construction industry, including:
  • Manufacture of construction glass (safety, insulating and solar glass)
  • Cement and concrete additives: superplasticisers, setting accelerators, pH regulators
  • Paints and coatings: stabilisation and increased durability
  • Cleaning agents: removal of cement residues, algae and soot
  • Metal treatment: degreasing before painting
Its alkaline properties support both construction chemistry and surface cleaning.

Sodium carbonate in the energy industry

In energy production, sodium carbonate is used to neutralise acidic exhaust gases in power plants and industrial facilities, binding sulphur dioxide (SO₂) and nitrogen oxides (NOₓ). Other applications:
  • Production of lithium carbonate for lithium-ion batteries (e-mobility, energy storage)
  • Production of solar glass for photovoltaic modules
  • Component of molten salt in solar thermal power plants for heat storage
Sodium carbonate thus contributes to decarbonisation and sustainable energy management.

Sodium carbonate in the plastics and polymer industry

In polymer production, sodium carbonate acts as a mild alkali, catalyst and cleaning additive. It supports polymerisation processes, particularly in the manufacture of PVC, acrylic glass and expanded plastics. Other applications:
  • Flame retardants and blowing agents in foams
  • Recycling processes: removal of additives and colour residues
  • Surface treatment: improvement of adhesion and stability

Sodium carbonate in the rubber and caoutchouc industry

In rubber processing, sodium carbonate stabilises the pH value and prevents the formation of acids. It improves vulcanisation, serves as a blowing agent for expanded rubber products and promotes adhesion to metals and textiles. Typical applications can be found in tyres, conveyor belts, seals and shoe soles.

Sodium carbonate in the lubricant industry

In lubricant chemistry, sodium carbonate is used to produce heat-resistant sodium soaps for high-temperature lubricants. It stabilises the pH value in biodegradable lubricants and protects against corrosion and wear. It also serves as a cleaning and degreasing agent for machines and workpieces.

Summary

Sodium carbonate (soda) is one of the most important inorganic base chemicals worldwide. Its wide range of applications - from glass manufacturing, cleaning, food processing, pharmaceuticals and construction chemicals to energy and polymer technology - demonstrates its industrial versatility. Thanks to its alkaline, pH-regulating and neutralising properties, sodium carbonate is a key technical and ecological component of modern industrial processes.