Abstract: An apparatus for extracting components of solids, by means of a liquid contacting the solids in counter-current flow, comprises a rotating drum with a substantially horizontal axis, which drum has generally axial compartments extending from one end to the other. The materials to be extracted and the liquid are supplied to opposite ends of the compartments. The compartments have along a cross-section at right angle to the drum axis in the general shape of a circle sector the apex of which merges with the drum axis. At least those walls of the compartments extending generally radially are pervious to the liquid and the liquid level inside the drum is lower than the drum axis level.