The invention relates to a shaft furnace (10) and a method for heat treating carbonaceous molded parts, particularly anodes (17), having an arrangement of the molded parts in at least one molded part column (11 to 15) disposed between tempering shaft devices (19, 20, 21) comprising a plurality of molded part rows (16) disposed above each other in a conveyor shaft, the rows being moved past temperature fields of the tempering shaft devices (19, 20, 22) and passing through a heating zone (25), a firing zone (27) having a burner device (28), and a cooling zone (26), wherein thermally insulating intermediate layers are disposed both between the temperature fields of the tempering shaft devices (19, 20, 22) and between the molded part rows of the molded part columns.