Process for the extraction of substances from at least one silane-modified oxidic or silicatic filler, wherein at least one gas compressed by means of pressure and/or temperature is employed as the extraction agent and the compressed gas is led in the radial direction through the filler in the pressure container and/or the substances extracted from the silane-modified filler are removed from the compressed gas with a suitable sorbent. A device for carrying out the process is furthermore described, wherein this comprises at least one pressure container having at least one internal container, sieve or insert for accommodation of the fillers which is permeable to gas and at least one gas feed and gas removal in the bulk bed of filler, and has a radially designed gas feed or gas removal from the bulk bed of filler.