Abstract: A ring section furnace device for the calcination of carbon bodies includes a number of serially connected chambers with or without lids on top. Each chamber contains a number of cassettes the walls of which have therein vertical and/or horizontal flue gas channels. A flue gas exhaust system from each chamber leads to a main ring duct. The furnace is fitted with an additional, separately attached ring duct, and each of the chambers is fitted with a recovery device in the form of a lid, manifold, or a similar device with a closeable opening or joining pipe, which allows for exhaust removal of the air used for cooling the cassettes through a pipe connection fitted between the additional ring duct and the recovery device on the chamber.