| abstract |
Particulate solids of water-soluble, fertilizer materials are prepared by dispersing a substantially anhydrous spray of molten and discrete droplets of the fertilizer material into a liquefied, volatile, cooling medium. Suitable cooling media include liquefied air, nitrogen, ammonia, carbon dioxide, or C1 to about C5 alkanes and halogenated derivatives thereof. The molten fertilizer material is preferably dispersed as discrete droplets having sizes from about 0.04 to about 0.30 inch by spraying the molten material into the liquefied cooling medium. The material is permitted to reside in the cooling medium a sufficient time to cool the material to below its freezing point and thereby form the particulate solids which are thereafter separated from the liquid. Any vaporized liquid can be recovered and refrigerated for reuse in the process. Urea is a preferred fertilizer material. |