A slag door is positioned in the side wall at the back of the furnace. This opening is used by the operator for visual inspection of the inside of the furnace, injection of oxygen and carbon using consumable lances, and for deslagging.
During slag foaming, slag is continuously pouring out through the slag door and a limited deslagging is achieved.
A more deliberate deslagging is made whenever a new slag is needed in order to perform the next metallurgical operation. This is always the case when a shift in oxygen potential is needed, e.g. shifting from highly oxidizing operating conditions to reducing conditions.