Abstract: Method for separating materials of different specific gravities using a centrifugal separator of the type comprising a bowl having a base and a peripheral wall surrounding a vertical axis about which the bowl rotates and a jacket having a base plate under the base of the bowl and a sleeve surrounding the peripheral wall includes a central bottom discharge for the concentrate. The bowl is mounted on the shaft with a hub connecting the shaft to the base plate of the jacket. Water is supplied through the shaft and into the area of the base of the bowl. Tubular discharge ducts extend from holes in the base plate across the space under the bowl to the base of the bowl. These remain open during processing of feed materials supplied to the bowl through a vertical tube feeding onto an imperforate plate carried by the bowl above the tubular ducts, and allow the concentrate washed down from the wall of the bowl to discharge when the feed and the centrifugal action of the bowl are halted.