Prilled

Prilled is an adjective used to describe a material that has been formed into small beads or pellets through a prilling process. A prill refers to a single bead, and prilled products are typically uniform, spherical or near-spherical in shape. Prilled materials are produced for ease of handling, storage, and controlled release in various applications.

The prilling process involves discharging molten or viscous material through a nozzle into a cooling medium, such as air or inert gas, inside a prilling tower or similar apparatus. As the droplets descend, they cool and solidify into discrete beads. The resulting prills are then cooled, screened to a target size distribution, and often coated or treated to improve flow, stability, or delivery characteristics.

Common uses of prilled products include fertilizers and industrial chemicals. In fertilizers, prills are used for products such as urea prills, ammonium nitrate prills, and single or compound fertilizer prills like monoammonium phosphate (MAP) or diammonium phosphate (DAP). Prilled forms offer advantages in handling, reducing dust, improving flow, and enabling uniform application. In the explosives and mining sectors, prilled ammonium nitrate is used as an oxidizer in prilled form, while prilled materials are also employed in pesticides and certain specialty coatings or carriers.

Characteristics of prilled products vary with material and process conditions but typically emphasize spherical shape, narrow size distribution, low dust generation, and good bulk handling properties. The term “prilled” may also be used descriptively for other substances manufactured as prills to facilitate transport, storage, or controlled release.