METHOD FOR CIRCULATION VACUUMIZING OF LIQUID METAL, SYSTEM AND APPARATUS FOR ACCOMPLISHMENT OF METHOD Russian patent published in 2003 - IPC

FIELD: ferrous metallurgy, in particular, production of low-carbon steel. SUBSTANCE: method involves purging melt surface with oxidizing gas supplied from central tuyere in vacuumizer dome while heating melt for intensifying decarburization reaction by burning of combustible gas; simultaneously supplying gaseous agents into suction branch pipe of vacuumizer; providing additional purging of melt surface with oxidizing agent from side tuyeres positioned in vacuumizer walls. Melt is heated by burning of combustible and waste gases supplied from central tuyere, which is made in the form of combined multilayer water- cooled tuyere. Flow rate of oxidizing gas supplied from central tuyere and side tuyeres is regulated depending on intensity of decarburization reaction. End surface of central tuyere head is positioned at distance from chamber bottom of at least 0.8 of chamber height. Heads of side tuyeres are positioned at distance from chamber bottom, which is not in the excess of 0.5 chamber height. Multiple-channel tuyere is equipped with two layers of nozzles for supplying of oxidizing gas and with central nozzle for supplying of combustible gas. Lower layer nozzles are oriented so that their axes intersect with axis of central nozzle below central tuyere head, and axes of upper layer nozzles are oriented along vacuumizer surface. Side tuyere arranged below the level of melt surface is arranged in chamber wall at distance from chamber bottom making less than 0.1 of chamber height, at vertical inclination angle less than 15 deg to chamber bottom. Tuyere axis is arranged in vertical plane, which intersects suction branch pipe surface, at distance less than 0.8 the radius of suction branch pipe from axis of said branch pipe. EFFECT: intensified process of decarburizing steel with extra low carbon content, simplified processing of steel melts of different steel grades. 71 cl, 22 dwg