| 摘要 |
<p><PICT:1097811/C6-C7/1> Pig iron is refined in a vessel e.g. a converter by top blowing an oxidizing gas, such as oxygen containing slag-forming materials e.g. lime or limestone in suspension, on to the molten pig iron covered with a foaming slag which is at least partly removed from the vessel during at least part of the refining operation, e.g. through a slag-overflow opening 2 in the side of the vessel 1 (Fig. 4). The top blowing may be effected with a lance 5 placed between the opening 2 and the vessel axis and producing a jet inclined downwards away from the opening. A cover 4 is preferably provided to pressurize the inside of the vessel. An opening 3 may be provided at a level higher than that of opening 2 for tapping molten iron when the vessel is turned down. Foam-promoting materials such as iron or chromium oxide, graphite or magnesia may be introduced into the vessel. The slag being removed preferably contains 20% or less of iron and at least 14% P2O5. Silica or other Si compound may be added to the slag after removal to keep the ratio of SiO2: P2O5 in the slag above 0.3. The slag may overflow continuously from the refining vessel into a decanting vessel, then into a slag container. Also the metal may overflow continuously into a secondary top blowing refining vessel by adding metal to the primary refining vessel. A three-stage cascade continuous process may be used. Scrap may be added to the refining vessel. The slag removed may be granulated pneumatically or by liquid jets.</p> |
