Controlling nucleation, growth and particle size distribution in ammonium diuranate precipitation

In general, the ammonium diuranate (ADU) particles formed from a uranyl fluoride solution are much coarser than those formed from a uranyl nitrate solution at comparable concentrations. It was demonstrated that the ADU particle size distribution can be tailored to suit certain particular applications by adjusting the uranyl fluoride to uranyl nitrate ratio in the feed stream. This phenomenon is explained satisfactorily in terms of the free uranyl ion concentration. The low population of free UO/sub 2//sup +2/ ions in the fluoride solution favors particle growth while the high population of free UO/sub 2//sup +2/ ions in the nitrate solution favors nucleation.