An industrial dryer particularly suited for washed silica sand. Drying takes place without heat from combustion. The dryer is constituted by a vertical axis cylinder with 4 internal bulkheads, in the first 2 inner bulkheads the water is separated from the sand by the centrifugal force. In the third and fourth bulkhead the water is mainly separated from the sand by means of the depressurization caused by the cylinder rotation and by a draft fan connected to the outer edge of the cylinder.