Abstract: The apparatus comprises around a nozzle supplying the mixture to be treated, a rotating sealed enclosure wherein an annular partition separates two chambers communicating together via a peripheral passage, containing chiefly the separated heavy phase and light phase and provided with thresholds for the draining thereof. According to the invention, the two chambers are equipped with separate centrifuge devices, connected to apparatus for driving them in rotation, which apparatus moves them at different angular speeds. The invention finds an application for example in the extraction of animal and vegetable fatty substances, in the extraction of essential oils, in the production of fat-free animal proteins, in the recovery of polymers from solvent-water mixed mediums, in the extraction of antibiotics, in metallurgical refinings with selective solvents, in the desalination of sea water by the solvent method, in the treatment of waste waters, etc.