Rotary processors and devolatilizing methods for particulate materials

Abstract

Novel rotary processors and methods which provide extremely efficient devolatilization of particulate materials which contain substantial amounts of volatiles and in which the boiling point of the volatiles presents separation problems. The processors and methods involve a rotatable element carrying a plurality of annular channels and a stationary element providing a coaxial closure surface operationally arranged with the channels to provide enclosed processing passages. Each passage includes inlet means, outlet means and a channel blocking member all associated with the stationary element and arranged and adapted so that material fed to the inlet can be carried forward by the rotatable channel walls to the blocking member for discharge from the passage. The passages are interconnected by material transfer grooves formed in the closure surface and are arranged to provide at least a melting stage and a devolatilizing stage which operationally communicates with a vacuum source. In the preferred embodiment, particulate material sprayed with a devolatilization aid or carrier substance is fed to the melting stage through a vacuum hopper, melted, collected and transferred through a strand die mounted at the inlet to the devolatilizing stage. The material in the form of thin strands undergoes unrestricted flash foaming while falling a predetermined distance into the devolatilizing passage, is carried forward, collected, sheared to release the volatiles and is discharged from the devolatilizing stage.