What is spray drying? 

Just a follow-up question that I thought of while watching your videos: what study materials do you recommend for understanding these unit operations better?

Thank you very much for your lovely words - I'm glad you found the video useful :)

I like both Aulton's Pharmaceutics and Remington's Pharmaceutical Science, but I have to admit I usually turn to RU-vid for the best information!

Thank you - and good luck in your exam

You're welcome :)

Thank you - Glad you liked the video

I think that depends on what you mean by agglomeration. Spray drying has the material to be dried dissolved or suspended in a solvent (not necessarily water). There is also a process called spray congealing (which I am thinking is closest to agglomeration), in which there is no solvent - rather the material is melted and forced through an atomising nozzle into a cold chamber where it cools and solidifies - this is not a method of drying though, as no solvent is being removed.

Agglomeration is an aspect of multi stage spray drying where fine particles collected in the cyclones and bag filters are recycled back to the drying zone. The recycled dry particles stick to the wet particles before they dry fully and this creates an agglomerated product, or a single product made of several smaller particles stuck together. Agglomerated products usually have a more controlled final product size and dissolve in water better than fine powders. Infant formula is a very common agglomerated product.