Abstract: A process and apparatus for drying wet solid material are provided. The process comprises introducing material into a dryer, bringing it into contact with one side of a plurality of heated surfaces located therein and vaporizing liquid in the material. The liquid is withdrawn from the dryer, compressed to a pressure greater than in the dryer and returned to the other side of the heated surfaces where, upon condensation, latent heat energy is released therefrom and used to vaporize liquid in material on the opposite side of the heated surfaces, withdrawing the condensate from the heated surfaces and substantially dried solids from the dryer.The apparatus comprises a housing having entrance and exit openings and means for delivering material into and dried material therefrom located in the openings and isolating the dryer interior from the outside atmosphere. A plurality of hollow heat exchange means connected to an external heat source and to atmosphere are disposed in the interior of the dryer.