GB666172A - Improvements in or relating to the heat treatment of finely-divided solids - Google Patents

Abstract

<PICT:0666172/III/1> <PICT:0666172/III/2> In a kiln for the heat treatment of solids, e.g. lime, in a single-stage fluidizing process, the finely divided solid material is fed through an inlet passage 16 into a rotating disc 17 which spreads it over chequer work 18, through which it falls counter to the hot gases rising from the fluidized bed of solids 13 which may be supplied with liquid, gaseous or pulverized fuel through a pipe 21 and with heated air through the perforated shelf 19. Treated material passes down the tube 20 to a valve controlled outlet 27 over perforated conical grates 23, 25 cooled by the passage therethrough of the incoming air supplied at 29, and waste gases taken off by a tangentially disposed outlet 11 may be partly recirculated to the fluidized bed. The solid material may alternatively be supported in bulk over a slotted plate in which the slots are covered or uncovered by oscillatable strips, or on a vibratable perforated plate, waste gases being taken off through inverted U-shaped flues over which the bulk material falls. In a further modification, Fig. 5, material fed from a hopper 40 passes downwardly over a series of baffle plates 41 and refractory deflectors 42. The valve 27 in the discharge tube 43 preserves a fluidized bed 13 of constant depth either manually or automatically in accordance with the air pressure below the bed.