A method of extracting a liquid phase from a suspension, the method comprising: injecting said suspension into a duct presenting a first section that is straight and a second section that is curved; and at the outlet from said curved section of the duct, extracting a liquid-enriched fraction of said suspension that is spatially separated from a particle-enriched fraction of the suspension; the method being characterized in that the injection flow rate of the suspension and the geometry of the duct are selected in such a manner that: in the straight section, lift forces cause particles to be superconcentrated in a ring around the longitudinal axis of the duct; and in the curved section, Dean secondary flows deform said ring and give rise to spatial separation between said liquid-enriched fraction and said particle-enriched fraction. A device for implementing such a method.