RECOVERY OF PARTICULATES USING MICROWAVE ENERGY

摘要

There is provided apparatus for the recovery of foundry sands including a fluidized-bed preheater (14) having a controlled inlet (16) for comminuted waste foundry sand and heated air supply annulus (17), preheating material to between 200 & 300 DEG C using recycled heat. The controlled inlet (16) is operable to allow air entraining dust to pass to a cyclone separator (21), air heat values being recovered into the feedstock. Preheated materials pass through outlet (23) to a main reaction assembly (24) comprising a microwave containment chamber (25) having microwave input assemblies (26) and containing an open-topped, annular vessel provided with vibratory means for circulating the material about the annulus. An overflow lip allows treated material pass through a controlled treated-material outlet (27) from the chamber (25) to a finishing assembly (30) comprising a fluidized bed finishing/cooling chamber (31). Control of the treated material outlet (27) permits heated air and dust to pass into an exhaust riser (34) including a diverter directing air at greater than 400 DEG C to the preheating chamber (15), and directing air at less than 400 DEG C to the cyclone separator (21), heat values in the separated cyclone air being recovered into the feedstock. Finished material passes to storage. Application of microwave energy to the pre-heated material circulating in the annulus increases its temperature to the ignition temperature of the resin coating.