Sublimation is the process of conversion of a solid directly to a gaseous state.
this method can be use to separate a volatile substance from a mixture.
for example lets take a mixture of iron fillings and iodine(iodine is a volatile material).in a china a funnel upside down on it .Close the funnel with a cotton ball. now heat the dish. Iodine sublimates  and settle on the walls of the funnel.hence the mixture is separated.
Sublimation is process in which solid is direct convert to vapour. Simple example of sublimation is dry ice, naphthalene balls, camphor, iodine crystals etc.