Two types of baking furnaces are in use:
Carbottom furnace:
Here the extruded rods are placed in cylindrical stainless steel canisters (saggers). To avoid the deformation of the electrodes during the heating process the saggers are also filled with a protecting covering of sand. The saggers are loaded on railcar platforms (carbottoms) and rolled into natural gas- fired kilns.
Ring furnace:
Here the electrodes are placed in a stone covert cavity in the bottom of the production hall. This cavity is part of a ring system of more than 10 chambers. The chambers are connected together with a hot air circulation system to save energy. The voids between the electrodes are also filled with sand to avoid deformation. During the baking process, where the pitch is carbonized, the temperature has to be controlled carefully because at the temperatures up to 800°C a rapid gas build up can cause cracking of the electrode.