Sulphuric Acid

Sulphuric acid is a highly corrosive strong mineral acid with the chemical formula H₂SO₄, widely used across multiple industrial sectors and ranking among the most produced chemicals globally. It is a dense, colourless to slightly yellow viscous liquid that is soluble in water at all concentrations, releasing significant heat upon dilution. The acid is produced primarily through the contact process, in which sulphur or sulphur-bearing materials are burned to produce sulphur dioxide, which is then catalytically oxidised to sulphur trioxide and absorbed in water to form sulphuric acid. In the mining industry, sulphuric acid plays a critical role in the hydrometallurgical extraction of metals, particularly copper and cobalt, where it is used to leach ores and concentrates in heap leaching and tank leaching operations. Copper smelters often produce sulphuric acid as a by-product of roasting sulphide ores, capturing sulphur dioxide emissions and converting them into marketable acid, thereby addressing environmental concerns while generating revenue. The acid is also essential in the manufacture of fertilisers, particularly phosphoric acid and ammonium sulphate, and finds applications in petroleum refining, chemical synthesis, wastewater treatment and battery production. Major copper-producing regions in Africa, including Zambia and the Democratic Republic of Congo, rely heavily on sulphuric acid supply for their leaching circuits, with some operations importing acid or investing in on-site production facilities. The global sulphuric acid market is closely tied to the fortunes of the fertiliser and metals sectors, with demand fluctuations influencing pricing and trade flows. Handling and storage of sulphuric acid require stringent safety protocols due to its corrosive nature and the risk of severe chemical burns. The acid has been produced industrially since the eighteenth century, with the contact process becoming the dominant production method in the early twentieth century.