Hydrocyclones are equipments widely used by the mineral industry, but it is possible to highlight its operation in desliming, selective classification, thickening and pre-concentration. Our research group designed a new hydrocyclone. In this novel device, the conical section of a conventional hydrocyclone was replaced by a conical filtering wall and the equipment was named filtering hydrocyclone. During the operation of this novel hydrocyclone, besides the underflow and overflow streams, there is another stream of liquid, resulting from the filtrate produced in the porous cone. In the present work, the influence of vortex finder diameter (D-0) of a filtering hydrocyclone was analyzed by an experimental and CFD study. Data from a conventional hydrocyclone of the same configuration were also obtained. The results indicated that the performance of separation process was significantly improved with this new equipment. Depending on the specific functions of the separator (as a classifier or thickener) the best values of Do were also found for the filtering hydrocyclone. (C) 2013 Elsevier Ltd. All rights reserved.