FIXING-BLEACHING SOLUTION REGENERATION METHOD Russian patent published in 2008 - IPC C02F1/46 C02F103/40 C25C1/20 

FIELD: electrochemistry, namely processes realized with use of red-ox reactions on electrodes with three-dimensional porosity, possibly treatment of fixing-bleaching solutions for their secondary use and silver extraction.

SUBSTANCE: method comprises steps of cathode treatment of solution in flow-through electrode with three-dimensional porosity consisting of carbon fiber material and anode treatment. Fixing-bleaching solution is subjected in addition to second cathode treatment on flow-through electrode with three-dimensional porosity of metallized synthepon and then it is subjected to anode treatment on flow-through three-dimension porosity electrode of carbon fiber material. During first cathode treatment while using only flow-through three-dimension porosity electrode of carbon fiber material divided from counter-electrode by cation-exchange membrane, potential applied to electrode is more positive than that of starting of metallic silver extraction and electric charge quantity consumed for reducing Fe³⁺ is fixed. During second cathode treatment while using only flow-through three-dimension porosity electrode of metallized synthepon divided from counter-electrode by cation-exchange membrane, potential applied to electrode corresponds to limit electric current of silver reduction. During anode treatment while using only flow-through three-dimension porosity electrode of carbon fiber material divided from counter-electrode by cation-exchange membrane, potential applied to electrode corresponds to limit oxidation current of Fe²⁺. Electric charge quantity consumed for such treatment is the same as at first cathode treatment of fixing-bleaching solution.

EFFECT: improved efficiency and effectiveness of method for regenerating fixing-bleaching solutions.

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