in close proximity to the shell to pretreat the lime mud separating the pretreated lime mud from the flue gas flow conveying the separated lime mud into the lime kiln and calcining the separated lime mud in the lime kiln application_number US 63188909 A description the main parts of the apparatus shown in fig1 comprise a feed screw 1 a lime kiln 2 and a riser duct 3 in connection thereto and a dryer separation cyclone 4 the lime kiln comprises an elongated kiln shell having a feed end wall 7 and a discharge end wall 6 the interior 8 of the kiln is located between the end walls the kiln is devoid of a separate feed chamber flue gas chamber in connection with the kiln but the lower part 9 of the riser duct 3 is located in the interior 8 of the kiln and in this case the lower end of the riser duct forms also a kiln exit gas duct flue gases from the lime kiln flow upwards via this duct into the separator cyclone 4 lime mud is thickened in a lime mud filter 16 which is standing on the same floor level as the feed end 7 of the kiln 2.