At the present time, sulfuric acid (alternative spelling sulphuric acid) is one of the most highly consumed chemicals globally but it was probably not recognized before the 16th century. First, sulfuric acid was invented by Johann Van Helmont (c.1600) through destructive distillation of green vitriol (ferrous sulfate) and by burning sulfur. The leading major industrial demand for sulfuric acid was related to Leblanc process for producing sodium carbonate (developed c.1790). Sulfuric acid was manufactured at Nordhausen, Germany from green vitriol but it was expensive and not affordable. A process for its synthesis by burning sulfur with saltpeter (potassium nitrate) was first applied by Johann Glauber in the 17th century and improved commercially by Joshua Ward in England c.1740. Sulfuric acid was soon superseded by the lead chamber process which was invented by John Roebuck in 1746 and since developed by many other scientists. The contact process was originally improved c.1830 by Peregrine Phillips in England; it was little applied until a requirement for concentrated acid arose, especially for the manufacture of synthetic organic dyes.
The lead chamber process is used to produce much of the acid consumed to make fertilizers; it produces a relatively dilute acid (62%–78% H2SO4). The contact process manufactures a purer, more concentrated acid but also it needs purer raw materials and applying of expensive catalysts. In both processes sulfur dioxide is oxidized and dissolved in water. The sulfur dioxide is obtained by burning sulfur, burning pyrites (iron sulfides), roasting nonferrous sulfide ores preparatory to smelting, or by burning hydrogen sulfide gas. Some sulfuric acid is also made from ferrous sulfate waste solutions from pickling iron and steel and from waste acid sludge in oil refineries.