Abstract: A method of quantitatively separating uranium from specimens of natural water, especially sea water or from solutions which as to their composition are comparable to such specimens, while silica gel is provided for adsorbing the uranium. The liquid of the specimens or solution is conveyed over granular silica gel having an average grain diameter not exceeding 0.5 mm. The through-flow speed is so selected that the contact time period for the liquid with the silica gel amounts to at least 50 seconds, whereupon the uranium adsorbed on the silica gel is separated therefrom by elutriation with at least 0.1 normal oxidizing mineral acid. The volume of the elutriate utilized, should amount to at least twice the volume of the silica gel, and this proportion of the elutriate should, if possible, not be exceeded.