GB358621A - Process and apparatus for preliminary treatment of raw material mixed for cement burning - Google Patents

Abstract

<PICT:0358621/III/1> <PICT:0358621/III/2> <PICT:0358621/III/3> <PICT:0358621/III/4> In the manufacture of cement, the slurry, before delivery to the rotary kiln 1, is spread as a coating on bodies such as hanging chains or pieces of corrugated metal 6 which are traversed through a drying-chamber 4 outside the kiln and communicating therewith through a passage 7. The coating is effected by allowing the chains 6 to dip into a slurry tank 14, Fig. 3, by spraying through a nozzle or by means of discs 20, Fig. 5, or by pressing the plastic slurry on to the chains by means of rollers 41, 42, Fig. 7. The waste gases from the kiln 1 pass through the drying chamber in counter-current to the chains 6 which are suspended from the rotary cover 5. Disposed adjacent the passage 7 is a rod or roller 17 adapted to flex the chains and release them suddenly, this action, together with the impact against the wall 18 of the slurry tank or the wall of the spraying or pressing chamber, serving to dislodge the dried coating of slurry. In the modification shown in Fig. 5, the steam evolved in the spraying chamber 25, instead of escaping directly to the flue 13 leading to the chimney 2, is passed through a condenser 27 which encloses vertical pipes through which the slurry is fed upwardly to the spraying discs 20. In a further construction, the passage 7 connecting the drying chamber with the kiln 1 is replaced by a vertical shaft having perforated walls so that the whole of the gases from the kiln pass through the material which falls into the shaft from the chains 6. A screw is provided at the base of the shaft to feed the material into the kiln. Modifications are also described in which a vertical partitioned drying-chamber is employed, the hanging chains 6 being replaced by endless chains which pass from a slurry tank up one side of the partition, over a driving pulley, and down the other side of the partition to an agitating or flexing device which dislodges the dried coating.