Process for effecting sublimation in a fluidised bed sublimer

摘要

PICT:0821643/III/1 Material to be sublimed is added to a fluidised bed of inert solid above which a reduced pressure is maintained by a vacuum pump; vapours of the material leave the bed with the fluidizing gas, and inert solid is continuously or intermittently removed, purified, and recycled to the bed. Reduction of the grain size of the inert solid allows the gas throughout to be increased. As shown, raw material is introduced at A into fluidized bed sublimer B and sublimate collects in condenser C; vacuum is maintained by pump E which draws gas to the fluidized bed through heater H; inert solid is withdrawn at J, purified at K, and recirculated. An example describes the purification of anthraquinone using sand as the inert solid and nitrogen as the gas.ALSO:Anthraquinone is purified by a sublimation process which comprises adding the crude material to a heated fluidized bed of sand above which a reduced pressure is maintained by a vacuum pump; anthraquinone vapours leave the bed together with the nitrogen fluidizing gas and are condensed. The sand is continuously or intermittently removed, purified, and recycled to the bed.