Abstract: The invention provides a method for recovering metal beryllium from waste beryllium that has become radioactive in the reaction with neutrons, by converting the radioactive beryllium to halogenated beryllium with a halogen gas such as chlorine, bromine or iodine, and subsequently submitting the halogenated beryllium to thermal decomposition. In this way, the invention allows effective recovery of metal beryllium from waste, radioactive beryllium, thereby reducing production of radioactive wastes and ensuring an economical use of natural resources.

Abstract: Mo adsorbent for .sup.99 Mo-.sup.99m Tc generators has a skeleton structure having mainly repeating units represented by the general formula; ##STR1## wherein X is a halogen atom or alkoxide group having one to six carbon atoms, 10% or more of X is halogen, R is an alkylene, polymethylene, or carbon chain having unsaturated bond, repeating unit (D) is bonded to any one of repeating units (A), (B), and (C), the branch structure is controlled by the content of repeating units (A), (B), and (C), the adsorbent is insoluble in water and adsorbs selectively only Mo from an aqueous solution containing Mo, and elutes .sup.99m Tc generated from a radioactive isotope .sup.99 Mo. This Mo adsorbent uses .sup.99 Mo obtained from natural Mo by (n, .gamma.) method, therefore, a generator having the same size as conventional .sup.99m Tc generators is realized.