Preamble

In converter steelmaking, oxygen at supersonic speed is blown on hot metal to remove the impurities like carbon, silicon, manganese, phosphorus. During the blow the lance distance is decreased to make the oxygen available into the bath for carbon removal. A three phase dispersion consisting of slag/metal droplets/gas bubbles forms during the blow. It takes around 15 to 20 minutes to blow the oxygen for refining. The tap to tap time varies in between 50 to 60 minutes depending upon oxygen flow rate, hot metal composition, lance profile and steel chemistry. It is interesting to note that the oxygen blowing time and the tap to tap time do not depend significantly on the converter capacity. This lecture attempts to discuss the fundamentals of converter steelmaking practice  

Availability of oxygen

Oxygen is available energetically during the refining. The energetic availability of oxygen is obtained by passing a certain flow rate of oxygen through the nozzle as shown in figure 13.1