Lance structure for oxygen-blowing process in top-blown converters

摘要

Herein disclosed is a lance structure for use with a top-blown converter. The lance structure is constructed to include a cylindrical sheath having a bottom wall and a flux supply tube disposed at the center of the sheath and defining a passage for carrying slag-forming flux in a powdered form. Further inclusive are a plurality of oxygen supply tubes which are arranged in the sheath and around the flux supply tube and which define oxygen supply passages. From the oxygen supply tubes, there lead a corresponding number of Laval nozzles which have their exits opened in the sheath bottom so that the oxygen gas supplied through the oxygen supply passages may be blown in the form of supersonic jets to penetrate into the molten iron contained in the converter. The flux supply tube is formed with ports which are opened into the Laval nozzles just upstream of the exits thereof to feed the flux together with a carrier gas to the supersonic oxygen jets so that the carrier gas flows may merge into the oxygen jets. Thus, the powdered flux can be uniformly dispersed in the oxygen jets without wearing and damaging the inner walls of the Laval nozzles and can be carried by the jets deeply into the molten iron.