MANUFACTURE AND COMMERCIAL PRODUCTION OF CHEMICAL-GRADE ZINC OXIDE FROM STEELMAKING DUST

摘要

Since 1974 Toho Zinc has been operating a plant, located in its Onahama factory, to treat steel making dust and produce chemical grade zinc oxide. Since the inception of this operation, it has been considered most important not to generate another type of waste as a result of treatment of steel making dust which in itself is waste material. In this process, zinc is vaporized in the strong reduction atmosphere in the vertical electro-thermic furnace and recovered as chemical grade zinc oxide, while iron contained in the dust is recovered in the form of clinker which is metallic and can be used as raw material for arc-furnace steel mills and others. Lead content is also recycled for smelter use. The plant is currently treating approximately 50,000-60,000 tons of dust annually to produce 16,000 tons of chemical grade zinc oxide of satisfactorily stable quality. We are committed to continuing steady efforts to make further technological. progress and improvements in such areas as recovery and utilization of heat energy, the rate of recovery of valuable metals, and quality of the product.