the additional separation cyclone 5 a can be adjusted in reliable manner without any significant risk of clogging which is mainly ascribable to the fact that the lower temperature makes it possible to use generally known regulating means such as an ordinary regulating gate 5 b and the fact that the alkali in the gases will condense and settle on the particles in the gases in fig2 is seen a cement manufacturing plant which essentially corresponds to the one shown in fig1 and where the same reference designations are used for similar elements in the plant shown in fig2 the gases are directed from the additional separation cyclone 5 a via a separate system comprising a separate fan 18 hence the productive capacity of the plant can be maintained independently of the quantity of calcined raw material being extracted by means of the additional separation cyclone 5 a as is seen in fig2 the separate system comprises in addition to the discharge duct 14 two cyclone stages 5 d and 5 e into which the raw material for cooling the gases are introduced via the inlet 12 which is located in the gas duct which connects the two cyclone stages in which the gases are cooled and separated from the cement raw materials used for cooling before the gases are drawn through the fan 18 to a filter if incorporated which is not shown the cement raw materials separated from the gases in the lowermost cyclone stage 5 d are preferentially directed into the calciner 2 in which it is calcined together with the remaining cement raw material which is fed.