The fuming of Zinc and Lead from lead smelting slags is done since 1927. The process is a reductive evaporation of zinc and lead, which is normally done with carbon carriers and air addition. For a higher vapour pressure and faster evaporation zinc oxide has to be reduced to a metallic state at temperatures around 1200 to 1400°C. After reduction, it will evaporate immediately caused by a vapour pressure of more than 10 bar. The evaporated zinc bubble will leave the melt by itself or is collected by the introduced air. The efficiency of zinc fuming is in industrial cases up to 90%, but can reach up to 96% in experiments.