What is Sulfuric Acid?

Sulfuric acid (alternative spelling sulphuric acid) is a strong mineral acid with the molecular formula H2SO4. Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates. Sulfuric acid is soluble in water at all concentrations.

Sulfuric acid has many applications, and is a central substance in the chemical industry. Principal uses include lead-acid batteries for cars and other vehicles, ore processing, fertilizer manufacturing, oil refining, wastewater processing, and chemical synthesis.


As a strong mineral acid, Sulphuric Acid Hazards are numerous.  Sulphuric Acid should always be handled with appropriate regard to its potential hazards.  Sulphuric Acid hazards are generally as a result of its reaction with other materials.



Sulphuric Acid is stable but reacts with moisture very exothermically.  This reaction may enhance its ability to act as an oxidizing agent.  Substances to be avoided include most common metals, water, organic materials, strong reducing agents, combustible materials and oxidizing agents.  Sulphuric Acid hazards include a violent reaction with water.  When diluting concentrated Sulphuric Acid, great care should be taken to ensure that the acid is carefully and slowly added to water.  Never add water to Sulphuric Acid.  Sulphuric Acid reacts with many metals which may be rapid or violent and generates hydrogen gas which is flammable and an explosion hazard.



Sulphuric Acid is extremely Corrosive and causes serious burns.  Sulphuric Acid is highly Toxic, Harmful by inhalation, ingestion and through skin contact.  Ingestion of Sulphuric Acid can be fatal.  Skin contact can lead to extensive burns.  Chronic exposure to Sulphuric Acid may result in lung damage and possibly cancer.


Personal Protection

In order to minimise the risk of Sulphuric Acid hazards, when handling or working with Sulphuric Acid it is essential that Personal Protective Equipment (PPE) is worn; this may include safety goggles or face mask.  Acid resistant gloves should be worn.  Suitable ventilation is essential for the safe handling of Sulphuric Acid.  In the UK the use of this material must be assessed under the COSHH Regulations.



Sulphuric Acid is a Corrosive liquid which causes severe burns and serious eye damage so great care must be taken when handling the substance to minimise the risk of Sulphuric Acid hazards.  Any vapours or mists of Sulphuric Acid are Corrosive and severely Irritating.  Exposure to Sulphuric Acid may occur through ingestion, inhalation and skin or eye exposure. Sulphuric Acid is classed as Corrosive for Transport.

Sulphuric Acid causes exothermic reaction with water producing a large amount of heat.  It also reacts exothermically with alkaline substances.  Sulphuric Acid is Corrosive to metals and will react hazardously with metals to produce Hydrogen gas.

Sulphuric Acid is not flammable but will produce Toxic and Corrosive vapours during fire.  These are known as Sulphur Oxides.



Inhalation of aerosols will cause irritation of the respiratory tract and mucous membranes whilst inhalation may cause pulmonary oedema.  Long term inhalation of Sulphuric Acid causes damage to the pharynx.  Chronic exposure to aerosols will cause erosion of teeth.



Ingestion of Sulphuric Acid causes severe pain with risk of perforation, nausea, vomiting and diarrhoea.  Ingestion also causes burns to the mouth, throat and oesophagus.


Eye contact

Sulphuric Acid may cause conjunctivitis to the eyes.



Exposure the Sulphuric Acid may cause dermatitis.



Sulphuric Acid has a toxic effect on fish and algae.  It will pollute groundwater with a risk of contaminating drinking water supplies.  Sulphuric Acid is incompatible with organic substances, chlorate and carbides.


Waste Sulphuric Acid

Any residues or waste products of Sulphuric Acid must be treated as hazardous waste and not disposed of to drain.

Sulphuric Acid Uses

Sulphuric Acid uses are many and varied.  In brief terms, they include:-

  • Sulphuric Acid uses in the manufacture of Phosphoric Acid
  • Sulphuric Acid uses in the manufacture of Phosphate fertilizers
  • Sulphuric Acid uses in the manufacture of Trisodium Phosphate for detergents
  • Sulphuric Acid uses in the manufacture of iron and steel to remove rust or scale
  • Sulphuric Acid uses in the manufacture of Aluminium Sulphate
  • Sulphuric Acid uses in coagulation of paper pulp fibres into a usable surface
  • Sulphuric Acid uses in the manufacture of Aluminium Hydroxide which is used as a filter in water treatment plants
  • Sulphuric Acid uses to make Hydrochloric Acid via the Mannheim Process
  • Sulphuric Acid uses as a catalyst in the production of Nylon
  • Sulphuric Acid uses in the petro-chemical industry as a catalyst in the production of iso-octane (the octane rating in petrol)
  • Sulphuric Acid is used in diluted form as the acid in lead-acid batteries (Battery Acid)
  • Sulphuric Acid is used in the production of Hydrogen



Uses in Detail

As can be seen from the list above, Sulphuric Acid uses are numerous and Sulphuric Acid has been used in industry for many years.  Sulphuric Acid is classed as an important commodity chemical and the amount of sulphuric acid used by a country is a good general indication of that country’s industrial development.  Industrially developed countries will broadly have a higher usage of Sulphuric Acid than countries with little industrialisation.

The major use of Sulphuric Acid is for the production of Phosphoric Acid which, in turn, is used for the manufacture of Phosphate fertilizers.  Phosphoric Acid is produced when Sulphuric Acid is manufactured using the ‘wet method’ of manufacturing.

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