Ruthenium (4) reduction on mercury cathode from sodium chloride concentrated solutions

The results obtained during the investigation of Ru(4) electroreduction from concentrated chloride solutions on a stationary mercury electrode at potentials more positive that those of sodium amalgam formation are presented. Experiments have been conducted at 60 deg C in the NaCl solution (270 g/l) deaerated by nitrogen additionally purified of oxygen. The cell with divided cathode and anode spaces has been used. Ruthenium has been introduced into the cathode space in the form of ruthenium hydroxylchloride labelled by the 106Ru radioactive isotope. The ruthenium deposition rate has been determined by the reduction of solution radioactivity in time by means of the periodic selection of catholyte samples from the cell. Graphic differentiation of the curve, expressing the dependence of the solution ruthenium concentration on time has been used to determine the partial current of the Ru(4)→R(0) process. For polarization measurements the potentiostatic method has been used