Copper Sulphate: Copper Heated with Sulphur, Roasted to Sulphate and Leached (Thorpe)

Blue vitriol on the large scale from scrap copper, as Thorpe's Dictionary (1912) describes it: old copper plates are heated to strong redness, sulphur is thrown in to turn them to sulphide, and the sulphide is roasted at a lower heat to sulphate. The hot mass is thrown into dilute sulphuric acid, and the solution is settled, concentrated and crystallised to large blue crystals of considerable purity. Burning sulphur gives off sulphur dioxide: furnace with a flue. The picture: our diagram.