Abstract: There is disclosed an impedance-heated furnace for processing a nonflowable but conveyable material at the processing temperature comprising a nonrotating shell having electrical-conducting properties, and heated to a processing temperature using electrical impedance as the heat source. The shell includes an inlet and an outlet and a conveyor means, which also may be heated by impedance, for transporting or carrying the material along or through the shell. The resulting solids and any generated or volatilized gases are recovered separately.