prilling

noun

1. (uncountable)The solidification of droplets of molten material falling against an upward stream of air; used especially to agglomerate ammonium nitrate and urea for use as a fertilizer.

   “In air prilling, molten sulphur is sprayed from the top of a tower against an upward flow of air. As the sulphur falls, the sulphur droplets break into small droplets and cools into prills.”