METHOD AND AGGREGATE OF OUT-OF-FURNACE REFINING OF METAL SMELT Russian patent published in 1997 - IPC

FIELD: metallurgy, method and apparatus are used for out-of-furnace metal smelts treatment. SUBSTANCE: method of out-of-furnace metal smelts treatment provides for creation in evacuator over smelt surface of pulsing and modulated by frequency and amplitude rarefaction sufficient for creation of gasses partial pressures over smelt less than partial pressures of gasses in smelt and simultaneous blasting of smelt in it by inert gas. Gas is blown in by at least two sprays asymmetrically to evacuator chamber axis in limited along circumference of evacuator in its lower part section. Gas is blown in periodically with frequency in 0.03 - 5 Hz range and it is tuned in resonance to ladle smelt level oscillations. Simultaneously with it gas of adjustable composition with frequency of 30 - 300 Hz range is additionally blown in operational space over smelt surface in evacuator in that time intervals, that correspond to phase of low frequency pulses pressure increase. The best results are achieved with gas bowing-in sector is in 15 - 30 deg range and during gas sprays feeding in smelt at a depth defined by proposed formula. Method is realized by aggregate, that has additional pipeline for adjustable composition gas feeding coupled to oxygen lance with acoustic generator by at least two nozzles mounted asymmetrically to axis of chamber of evacuator unlimited section with central angle of 15 -40 deg and generator of pressure pulsations mounted on pipeline of inert gas feeding. Method and aggregate for out-of-furnace metal smelt treatment allows to increase degree of oxygen, hydrogen and nitrogen removal correspondingly by 14, 24 and 31.5 %. Amount of nonmetallic impurities in steel produced by the method decreased from 0.0065 to 0.0023 % or by 0.0032 %, that is by 31 % better, that it is in known method. In the case consumption of blown-in gas is decreased by 40 m³/h, refractory material erosion in zone of blowing-in also is decreased and quality of metal increased. EFFECT: method and apparatus allowed to decrease significantly consumption of blown-in gas and erosion of refractory material, to increase metal quality. 5 cl, 2 dwg, 2 tbl