In-situ observation of a dendrite growth in an aqueous condition and a uranium deposition into a liquid cadmium cathode in an electrowinning system

A zinc-gallium system was setup to observe the growth process of dendrites and to compare the performance of the stirrers which would prevent a dendrite formation. In a no-stirring condition, zinc was easily deposited on a liquid gallium cathode in the form of dendrites. It was difficult for a paddle stirrer to directly fracture the zinc dendrites to fine particles. However, a harrow stirrer was observed to fracture the dendrite to some extent at high speeds. Not only their rotation speed but also the length of their blades needed to be properly adjusted to enhance their performance. In the uranium-cadmium experiment, the diffusion coefficient of the uranium species was obtained by the cyclic voltammetry method, which is around 1 X 10(-5) cm(2)/s. In a no-stirring condition, most of the uranium deposited at the current densities of 35, 100 and 200 mA/cm(2) did not sink into the liquid cadmium cathode. (C) 2008 Elsevier B.V. All rights reserved.