The iron is melted in the hot air blast cupola furnace and is then
poured into the casting moulds. The hot air cupola has a melting capacity of 18
to 27 tons per hour and can melt basic iron for both nodular and grey cast
iron. The charging system is fully automatic and the cupola consists of a long,
vertical cylinder into which the charge is loaded from above. Hot air is blown
in near to the bottom around the melting zone where the temperature is
approximately 2000°C, enabling the iron and steel in the charge to melt. The
coke causes carburetion of the metal and removes any rust by deoxidization. The
entire process is controlled from the control room. The molten iron flows out
at the bottom through a tap hole, while on the other side of the furnace the
liquid slag is drawn off through the slag hole. The slag is used for road
building and the construction industry. Before the molten iron is used for casting,
thermal and spectrographic analyses are carried out in the lab to determine the
carbon and silicon content as well as other elements.