2017-1-1 · The flow chart of copper pyrometallurgy. Special metallurgy is a branch of pyrometallurgy mainly pointing at the needs from high-tech, defense areas, etc., such as high-quality special steel, refractory alloys (eg, tungsten, molybdenum, niobium, tantalum), active metals (eg, titanium, zirconium), highly purified metals (eg, zero-inclusion steel).