| 摘要 |
PURPOSE:To selectively reduce Fe<3+> ions in a plating soln. to Fe<2+> ions by using an electrode having a specified hydrogen overvoltage as the cathode in an electrolytic cell divided into cathode and anode chambers with an ion exchange membrane and by introducing the plating soln. contg. Fe<3+> ions at a proper concn. into the cathode chamber. CONSTITUTION:An electrode having 50-350mV hydrogen overvoltage is used as the cathode in the electrolytic cell divided into the cathode and anode chambers with the ion exchange membrane. A plating soln. contg. <=7g/l Fe<3+> ions is introduced into the cathode chamber, an electrically conductive soln. into the anode chamber and the Fe<3+> ions in the plating soln. are reduced to the Fe<2+> ions. The cathode having 50-350mV hydrogen overvoltage is obtd. by coating a Raney nickel or bulb metal with powder of a Pt family element or etching a stainless plate so as to regulate the specific surface area to >=1,000m<2>/m<2> measured by a nitrogen gas adsorption method.
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