METHOD OF TOP BLOWING OF OXYGEN-CONTAINING GAS THROUGH METAL MELT AND LANCE FOR TREATMENT OF METAL LIQUID MELT Russian patent published in 1999 - IPC

FIELD: metallurgy, particularly, methods of top blowing of oxygen-containing gas with and without solid substance through metal melt found in vacuum in metallurgical vessel with the aid of lance for method embodiment. SUBSTANCE: method and lance are offered for performance of various operations of metal melt, treatment with increase of content of separate introduced media by simple means without design readjustment. Devised multipurpose lance allows top blowing of oxygen with solid substance or without this substance and formation of focal flame. For each operation of method, only separate supplying pipeline are engaged by respective manner. According to blowing method, first produced inside lance is circular flow of oxygen or oxygen-containing gas which after preset section is expanded to produce continuous flow with circular cross-section. When moving further the flow encounters in its exterior zone an obstacle in the form of circular screen (reflecting ring) for excitation of vibrations in gas flow passing towards melt. Gas flow passes through hole of circular screen and critical diameter of lance outlet hole in the form of Lavla nozzle. Gas flow is directed from lance into metal melt at supersonic velocity. To produce focal flame in free hollow of metallurgical vessel, oxygen or oxygen-containing gas may be supplied to metal melt at supersonic velocity at lance outlet. Reflecting ring is fastened in lance on internal surface of tube for oxygen supply and located before narrowing of Laval nozzle at a distance Lb in direction of oxygen flow from its critical diameter. Fastened inside oxygen supplying tube on its top end coaxially to it is tube whose lower end is located at distance Lp before reflecting ring, in direction of gas flow. EFFECT: higher efficiency. 21 cl, 5 dwg