Formation of a porous material upon electrochemical leaching of a homogeneous gold-containing alloy

The phenomenon of structural reorganization of the initial homogeneous allo y of gold with copper, silver, and some other metals, which form continuous series of solid solutions with gold, was discovered during the development of a new method of electrolytic refinement of gold-containing alloys in an attempt to obtain high-purity gold. During electrolysis, the anode is tran sformed into a porous material composed of monodisperse micron-sized uncut gold particles having the form of small curved cylinders with rounded edges . The particles are interconnected with bridges similar to those formed upo n sintering, so that the end product with a porosity as high as 80% will be strong. It is suggested that the transfer of gold atoms, releasing base me tals from an alloy into solution and thus resulting in the formation of pur e gold particles, is provided by surface diffusion, which is probably promo ted by electrode polarization and chemisorption processes.