Abstract: A method for the production of spherically shaped granules of low melting point, corrosive, subliming substances which comprises melting the substance and discharging the melt through a perforated bottom receiver and into a prilling tower in the form of a plurality of streams having diameters of 0.5 to 4.0 mm which form droplets as they fall through the tower. The prilling tower has 10 to 20 mm diameter lateral perforations through each of which a mixture of air and an atomized liquid, with a lower boiling point than the melting point of the subliming substance, is introduced to form a mist. The mist is cooled below the atmospheric temperature and transformed into a low temperature fog which minimizes sublimination. The droplets are solidified as they pass through the fog during their fall through the tower and form granules having a diameter of 0.5 to 4.0 mm which are received on a curved screen to prevent breakage.

Abstract: A method for fast cooling granules of low melting point, subliming substances obtained by a prilling process. The granules are in the shape of a plurality of droplets having diameters of 0.5. to 4 mm and are formed from a prilling column with the droplets partially solidified by means of a countercurrent air cooling. The partially solidified particles are received in an inert liquid in which the substance is insoluble. The liquid also has a lower boiling point than the melting point of this substance. The solidified particles are separated from the liquid before being completely cooled so that their remaining heat content evaporates any residual liquid from the particles.