PRECIPITATION OF MONODISPERSED MIXED COPPER GADOLINIUM BASIC CARBONATE PARTICLES

This work describes the co-precipitation behavior of copper(II) and gadolinium(III) from solutions that become homogeneously alkaline by the forced hydrolysis of urea at 75-degrees-C. After a rather short induction period, amorphous mixed copper-gadolinium basic carbonate uniform spherical particles precipitate. The average gadolinium-to-copper ratio in the resulting solids depends on the initial system composition, and is strongly influenced by aging time; particles precipitated at short aging times are richer in copper, whereas the gadolinium-to-copper ratio in the particles obtained after prolonged aging is higher than that in the starting solution. The experimental results indicate that nucleation of amorphous copper hydrous oxide promotes the formation of the mixed solid phases. The influence of each metal ion on the hydrolysis-complexation-precipitation behavior of the other is discussed. The results are used to make a general assessment of the limitations and advantages of the various possible ways of preparing precursors of mixed oxides by wet procedures.