Refining of hot metal

After the previous heat is tapped and slag is drained, lining is inspected. Scrap and hot metal are charged. Converter is tilted into the vertical position and the lance is lowered in the vessel to start the blowing. Selection of the starting lance distance is such that the concentration of the force at the bath level should not cause ejection of tiny iron particles (sparking) and at the same time maximum bath surface area is covered by the oxygen jet. The starting lance distance  for specific oxygen blowing rate  can be calculated by

 

  is bath diameter in meter. For 150 Tons converter, and , when oxygen flow rate is approximately .

Initially oxygen is blown soft by keeping lance distance higher to promote slag formation and to avoid ejection of small particles, because hot metal is not covered by slag. Lime may be added either at the beginning of the blow or in portion during the blow. Oxygen is blown for nearly 15-20 minutes by progressively decreasing the lance distance such that slag foaming remains under control and oxidation reactions occur uninterruptedly. Slag and metal samples are analyzed.