Triple chamber furnace for scrap segregation and melting

Abstract

Scrap vehicles, mixtures of iron and aluminum, plastics are often pressed into bales or cubes to reduce the cost of transportation and storage to a smelter. Considering the dwindling number of large smelters in the United States due to the high pollution associated with coke fired cupolas, a new invention is developed to use natural gas, diesel fuels and clean fuels and hydrocarbons from scrap plastics in the bale. The process consists of three steps. In the first step the scrap bale is heated in a chamber up to temperatures of 1000° C. to promote the vaporization of zinc from galvanized steel, the pyrolysis of any plastics or scrap tires in the bale, and the separation of aluminum and magnesium by melting. The heat for this first stage is transferred through flue gases rising from the second and third stages after passing through a recuperator. The remaining scrap once separated from zinc, aluminum, magnesium and plastics is transferred to a second stage and melted and allowed to flow into a third stage where alloying and final removal of sulfur, phosphorus and other contaminants is completed in the hearth under a reverberating flame. Flue gases rising from the first stage are passed through condensers to precipitate vaporized zinc, and to convert hydrocarbons into fuel that is burned in the third stage burner above the hearth.