METHOD FOR REGENERATION OF THE CHROMIUM PLATING ELECTROLYTE Russian patent published in 2023 - IPC C25D21/18 

FIELD: electroplating technology.

SUBSTANCE: invention relates to electroplating, in particular, to the regeneration of the chromium plating electrolyte and can be used in areas of chromium plating of steel products. The method includes electrochemical treatment of the regenerated electrolyte in a three-chamber electrolyzer consisting of a cathode chamber with a stainless steel cathode and containing a sulfuric acid solution separated from it by a cation exchange membrane of the middle chamber, which is a capture bath containing a regenerated chromium plating electrolyte, and an anode chamber with a lead anode separated from the middle chamber by an anion exchange membrane and containing a purified chromium plating electrolyte. A lead anode is additionally installed in the middle chamber. A solution of sulfuric acid with a concentration of 20-30 g/l is used in the cathode chamber. Regeneration is carried out in two stages at a current density of 2-4 A/dm² on lead anodes. At the first stage, anodic oxidation of trivalent chromium ions contained in the middle chamber is carried out with the formation of chromic acid by forming an electric circuit with a lead anode located in the middle chamber with a cathode located in the cathode chamber. At the second stage, the electrical circuit is formed by a cathode located in the cathode chamber and a lead anode located in the anode chamber, and without including the lead anode in the middle chamber in the electrical circuit.

EFFECT: elimination of trivalent chromium losses is ensured by obtaining the only waste: iron hydroxide.

1 cl, 3 ex