Abstract: A process is described for the extraction of one or more substances from a fluid starting material with an appropriate extraction agent by use of a static micromixer for mixing the starting material with the extraction agent. The static micromixer is provided with disk-shaped components, the disk (1) being provided with at least one inlet opening (2) for introducing at least one fluid stream into a linking channel (3) disposed in the plane of the disk and at least one outlet opening (4) for removing the fluid stream into a mixing zone (5) disposed in the plane of the disk, the inlet opening (2) being connected with the outlet opening (4) in a communicating manner through a linking channel (3) disposed in the plane of the disk, and the linking channel (3) before opening into the mixing zone (5) being divided by microstructure units (6) into two or more part channels (7), and the widths of the part channels being in the millimeter to submillimeter range and being smaller than the width of the mixing zone (5).