Which granulation process involves melting solids and reducing them to beads or powder by spraying the molten feed into a stream of air or other gas?

• A. Spray Congealing
• B. Spray Drying
• C. Spray Chilling
• D. Two of the Above

Answer: (D)

Think of processes that turn molten solids into small, solid beads as they travel through a gas stream. Two methods do exactly this: spray congealing and spray chilling. In spray congealing, the solid material is melted and sprayed into a gas; the droplets cool and solidify into beads or granules. In spray chilling, the molten or hot droplets are sprayed into a cooler gas and solidify into beads or powders. Both rely on melting first and then rapid solidification in flight.

Spray drying, by contrast, starts with a liquid feed and uses hot air to evaporate the solvent, producing powder rather than solid beads formed from melted solids. That’s why the best answer is the combination of the two methods that fit the description.