Raw meal sludge is dried in a vapor flow dryer by circulating exhaust vapor through a steam circuit which, prior to introduction thereof into the lower part of the dryer, is heated by indirect heat transmission from gaseous flows from a pre-heating system from a gas cyclone of a clinker production line. A partial vapor flow corresponding to water evaporated during raw meal sludge drying is removed from the steam circuit and extracted in the form of a condensate after increasing the vapor temperature by a vapor compressor and the passage of vapor arranged in the dryer over a heating surface of a vapor condenser. The sludge is sprayed into the lower part of the dryer where water is evaporated by the heat of the circulating exhaust vapor and heat from the condenser heating surface. Dried raw meal is separated from the exhaust vapor in a cyclone separator.