PROCESS AND DEVICE FOR BLOWING OXYGEN OVER METAL MELTS

摘要

The invention relates to a process and device for blowing oxygen over a metal melt under a vacuum. The oxygen is to be applied over a large surface with a large intermediate phase area while avoiding overcooling in the metal bath by simple, easily maintained structural means. To this end the flow of oxygen in the lance is accelerated and compressed in pulses. The plug-shaped oxygen pulses leaving the lance in succession extend in a bell shape in the vacuum above the melt, with the cores of the oxygen bubbles moving at a similar speed to the casings. At the base of the wall (41) of the blowing lance (40) there is an annular nozzle (42). At a distance behind the annular nozzle (42) in the direction of flow of the oxygen there is a blind tube (44) forming a fan-shaped compartment (43). Between the bottom (46) of the blind tube (44) and the head of the blowing lance (40) there is a pre-nozzle chamber (48) and in the head of the blowing lance (40) there is at least one nozzle (50) directed towards the melt, whereby the nozzle (50) takes the form of a Laval nozzle and has components (51) to stabilise the flow of oxygen.