A METHOD FOR ELECTROWINNING OF METALLIC CHROMIUM FROM ACIDIC WASTE ELECTROLYTES

摘要

The invention consists in an acidic electrolyte solution with a Cr(VI) ion concentration of more than 0.05 g/l being subjected to electrolysis using an anode made of steel or lead and a cathode made of steel, graphite or glassy carbon that is at least 10 times smaller than the anode, wherein the electrolysis is carried out potentiostatically or galvanostatically. For the lead anode, the cathode potential remains within the range from -2.9 V to -3.5 V and for the steel anode, the cathode potential remains within the range from -2.5 V to -3.0 V. The cathodic current density remains constant within the range from 0.06 A/cm 2 to 0.7 A/cm 2 in acidic solutions containing more than 50 g/l of chromium. Alternatively, the electrolysis is carried out using controlled current pulse, wherein the cathodic current density remains constant within the range from 0.06 A/cm 2 to 0.7 A/cm 2 in acidic solutions containing more than 50 g/l of chromium, and the pulse off-time is from 10 to 20% of the electrolysis duration, which is over 10 s.