Verfahren und Vorrichtung zum kontinuierlichen Behandeln von Korn- und/oder Staubgut mit Gas

1,040,063. Preheating cement raw materials. MIAG MUEHLENBAU UND INDUSTRIE G.m.b.H. Feb. 11, 1963 [Feb. 27, 1962], No. 5411/63. Heading F4B. [Also in Division BI] Granular or powdered material is treated with a gas by passing the gas upwards through a downwardly flowing stream of solid, the gas velocity being greater than the velocity at which individual particles of the material are supported by the gas, and the rate of feed of solid being such that clouds of material are formed which drop through the region of greatest velocity of the gas stream upon reaching a critical density. Material carried overhead is removed from the gas stream in a separator and returned to the vessel. As shown in Fig. 1, a reaction vessel having a tapering lower portion ending in a nozzle 3 is supplied with solid through line 12 and with gas from pipe 9. The gas passes around a flange 5 on the nozzle 3, and passes upwardly to suspend the descending solids. As the density of the solid clouds builds up, the cloud falls through the nozzle 3 and is collected by conveyer 11. Outgoing gases leave through line 13 and solids separated in cyclone 16 are returned to the reactor. A number of cyclone separators external to the reaction vessel may be employed, to some of which the incoming reactant is fed. The axis of the reaction vessel may be curved and in one case the nozzle 3 opens into the end of a rotary kiln used in cement preparation.