Spray-drying is a unit operation by which a liquid product is atomized in a hot gas current to instantaneously obtain a powder. The gas generally used is air or more rarely an inert gas as nitrogen. The initial liquid feeding the sprayer can be a solution, an emulsion or a suspension.
Spray-drying produces, depending on the starting feed material and operating conditions, a very fine powder (10–50 lm) or large size particles (2–3 mm)