Treating liquid effluent comprising zinc and nickel in solution in chloride medium, comprises conducting electrolysis of zinc and nickel solution in an electrolytic tank for dezincification and for nickel separation

摘要

The process comprises conducting electrolysis of zinc and nickel solution in an electrolytic tank (1) for dezincification and for nickel separation. The tank comprises: a cathode chamber that is charged with the zinc and nickel solution as a catholyte and is equipped with a metal cathode (4), where zinc is deposited when the cathodic solution is dezincified and nickel is deposited; and an anode chamber that is charged in an acid medium such as sulfuric acid as an anolyte and is equipped with a anode (9). The cathode and anode chambers are separated by a cationic ion exchange membrane (6). The process comprises conducting electrolysis of zinc and nickel solution in an electrolytic tank (1) for dezincification and for nickel separation. The tank comprises: a cathode chamber that is charged with the zinc and nickel solution as a catholyte and is equipped with a metal cathode (4), where zinc is deposited when the cathodic solution is dezincified and nickel is deposited; and an anode chamber that is charged in an acid medium such as sulfuric acid as an anolyte and is equipped with a anode (9). The cathode and anode chambers are separated by a cationic ion exchange membrane (6). The effluent is pretreated by adding sulfuric acid and separating formed precipitate. The electrolytic tank for dezincification has pH value of 2+- 0.2. A potential of the cathode in the tank is -700 to -750 mV. A temperature at which the electrolysis is conducted in the electrolytic cell for dezincification is 20-30[deg] C. The electrolytic tank for nickel separation has pH value of 0.5+- 0.2. A potential of the cathode in the tank for nickel separation is -450 to -550 mV. A temperature at which the electrolysis is conducted in the electrolytic cell for nickel separation is 60-70[deg] C. An independent claim is included for an installation for treating liquid effluent.