Process and equipment for melting scrap iron and scrap steel

摘要

In a process for melting scrap iron and scrap steel, scrap is fed through a shaft furnace in countercurrent to a reducing gas. The reducing gas is formed by air flowing through a plasma generator and coal and/or hydrocarbon being blown into the hot air in such a way that the (CO2 + H2O)/(CO2 + H2O + CO + H2) ratio of the resulting gas becomes smaller than 0.2. The energy required for melting is supplied as sensible heat of the reducing gas. The energy required for preheating the scrap is supplied by an oxygen-containing gas being introduced at a multiplicity of points along the flowpath of the reducing gas into the preheating zone, in particular for the stage-wise combustion of the reducing gas. The introduction of the oxygen-containing gas at the said multiplicity of points is adjusted to have the effect that the gas retains its reducing effect on the scrap metal at scrap temperatures above 1000@C and preferably even above 800@C. Furthermore, the invention comprises equipment for carrying out the process, the equipment consisting of devices which correspond to the various process features described above.