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

Abstract

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.