Abstract
The electrolytic oxidation of chromium (III) has been studied in a cell without diaphragm. Oxidation rate of chromium (III) into chromium (VI) increased with increases in pH, concentration and cathodic current density. PbO2 was found to be most preferable for the anode material due to the catalytic action of PbO2 for chromium. By increasing the cathodic current density or by using cathode materials of low hydrogen overvoltage, reduction of chromium (IV) at the cathode could be reduced. (NH4)6Mo7O24 which was used as additive, increased the anodic current efficiency by about 10%-15%. Since pH could be maintained at a value from 1.8 to 2.5 by constantly adding chromium hydroxide, chromium (VI) is recovered with good efficiency.
