Abstract: The present invention relates to a process for the continuous conversion of one hydroxylamine salt to another hydroxylamine salt, said process involving a countercurrent liquid-liquid extraction followed by a countercurrent liquid-liquid re-extraction. Characteristically, the extractant is used in the extraction step in the salified form and in the acid form.

Abstract: The invention relates to the recovery of acid organophosphorus compounds and/or organophosphate ions present in an aqueous solution.According to the invention, the aqueous solution is contacted with at least one organic amino compound which is not very soluble in water, chosen from among compounds having at least one amine function, the salts of these amino compounds and the quaternary ammonium salts and the complex formed is separated from the aqueous solution by reacting these acid organophosphorus compounds and/or organophosphate ions with the organic amino compound or compounds.The amino compound can be a trialkylamine, e.g. triisooctyl amine and contacting and separation can be performed in a co-current or counter-current liquid-liquid extraction installation.

Abstract: Process for the extraction of fission products contained in irradiated nuclear fuel elements which have been subject to a temperature of at least 1200.degree. C. during their irradiation prior to dissolving the fuel by the wet process. After mechanically treating the elements in order to decan and/or cut them they are brought into contact with water in order to pass the fission products into aqueous solution. The treated elements are then separated from the thus obtained aqueous solution. At least one of the fission products is then recovered from the aqueous solution. The fission products are iodine, cesium, rubidium and tritium.