Shigeo Matsubara

Acceleration of Reduction of Fe3+ Ion Emitted from an Insoluble Anode in Iron Plating Baths

To accelerate the reduction rate of Fe3+ ion emitted from an insoluble anode in continuous iron plating, a new process which uses an anion exchange membrane inserted between catholyte and anolyte, and batch-type rotary drum reduction reactor has been developed. The superiority of the proposed process has been ascertained by laboratoryscale experiments. In the proposed process, Fe3+ concentration in anolyte exceeding 10g/L could be allowed without any plating problem for total iron ion concentration below 160g/L and cathode current density up to 100A/dm2 Under a high Fe3+ concentration in anolyte, it has been demonstrated that the reduction of Fe3+ to Fe2+ by metallic iron particles in the reactor is quite effective. The employed membrane electroplating made it possible to decrease the quantity of Fe3+-concentrated anolyte The maximum Fe3+ reduction rate of 32g/L Fe3+ anolyte was 4.6g/L/min, which was 46 times that obtained with 2g/L Fe3+ anolyte.