Iron and other cationic impurities are usually removed from conventional chromium plating solutions by the electrolytic transfer through cationic membranes. This process is characterized by relatively high specific energy consumption due to very low transport numbers of cationic impurities. A reversed process is based on the recovery of pure chromic acid from contaminated solutions by the electrolytic transfer of chromate ions through an anionic membrane. This process is characterized by lower energy consumption and is especially efficient, when it is combined with the use of reclaim tanks in the chromium plating line. Anodic half-cells with anionic membranes are installed directly in these reclaim tanks and are used for the recovery and concentrating of chromic acid free of any cationic impurities.
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