A method of sintering cement clinker is provided including the steps of introducing raw material for cement to a spouted fluidized bed granulating furnace which includes a perforated distributor having a plurality of nozzle holes; passing fluidizing gas through at least one of the plurality of nozzle holes into the spouted fluidized bed granulating furnace while simultaneously blowing classifying gas at a selected flow velocity that is different from the flow velocity of the fluidizing gas into the spouted fluidized bed granulating furnace through a dropping port arranged facing and between the fluidized bed of the spouted fluidized bed granulating furnace and in communication with a fluidized bed sintering furnace; granulating the raw material in the spouted fluidized bed granulating furnace; discharging granules formed in the spouted fluidized bed granulating furnace into the fluidized bed sintering furnace while classifying the granules with the classifying gas; and sintering the granules injected into the fluidized bed sintering furnace through the dropping port.
