Abstract: A vapor atmosphere spray dryer can include a closed-loop circuit having a dryer, a bag house filter system, a fan, and a heater system which are fluidly connected together for circulating a mass of superheated vapor therethrough. A centrifugal atomizer is disposed within the dryer. A feed system delivers a supply of feed slurry to the centrifugal atomizer which discharges a supply of atomized feed slurry in the dryer for combination with the circulated mass of superheated vapor within the dryer. The closed loop circuit is constructed such that the circulated mass of superheated vapor has an operating pressure of at least 1 psi which is generated by the evaporation of the fluid in the atomized feed slurry in the dryer resulting from the combination of the supply of atomized feed slurry and the circulated mass of superheated vapor.