pyrometallurgia

Pyrometallurgy, also known as pyrometallurgia in some languages, is a branch of extractive metallurgy that uses high-temperature processes to extract and refine metals from ores, concentrates, and scraps. It involves chemical reactions driven by heat, including oxidation, reduction, sulfide oxidation, and volatilization. Common heat sources include coke and other fuels, and reducing agents such as carbon; the products are metal, slag, and off-gases.

Historically, pyrometallurgy is among the oldest metallurgical technologies, with early smelting of copper and iron in ancient and medieval times. The development of blast furnaces, reverberatory and flash smelting, and other high-temperature reactors in the 19th and 20th centuries expanded production of base and precious metals. Today it coexists with hydrometallurgy and electrometallurgy as a core metallurgical discipline.

Core processes include calcination and roasting of sulfide or carbonate ores to oxides; smelting to produce metal and a gangue slag; and refining, such as fire refining and converting, to reach desired composition. Specialized variants include flash smelting, matte smelting for copper and nickel, and bath smelting in electric furnaces.

Major metals produced include iron, copper, nickel, zinc, and lead, often via smelting and slag cleaning; refining steps separate impurities and recover value from byproducts such as sulfuric acid produced from sulfur oxides. Pyrometallurgy is energy-intensive and uses fluxes to form slag, which can be recycled.

Environmental considerations focus on emissions control, sulfur compounds, dust, and energy use; modern plants employ gas cleaning, sulfuric acid recovery, and integrated material and energy flows to reduce emissions and improve efficiency.