Photo: Rouyn-Noranda smelter | Credit: Sulphuric Acid on the Web. Glencore-Horne-Smelter (Aug 23, 2015)

The Fonderie Horne, operated by Glencore Canada in Rouyn-Noranda, Quebec, produces approximately 650,000 tonnes of sulphuric acid per year from sulphur dioxide (SO₂) generated during copper smelting, its main industrial activity. Commissioned in 1927 (smelter) and 1989 (acid plant), it is one of the largest integrated smelter-gas recovery units in Canada.. The process captures SO₂ from smelter off-gases and oxidizes it to sulphur trioxide (SO₃), which is then converted into sulphuric acid (H₂SO₄) via the contact process. According to Glencore, about 96 % of the sulphur dioxide emitted during smelting is recovered and transformed into marketable acid. Canada is a major player in the global sulphuric acid market, accounting for roughly 28 % of worldwide exports, largely through production from non-ferrous metal smelters such as the Horne facility.