Process for the removal of metallic impurities from nickel - and cobalt prevent electrolytic plating bae

摘要

Metal impurities in acidic nickel and cobalt solutions e.g electroplating solutions, are removed by adding sufficient barium or strontium oxides, hydroxides or carbonates to the solutions in order to raise the pH above 5 and filtering off the precipitated impurities. When chloride solutions are to be purified a slight excess of soluble sulphate may be added after the pH raising stage to precipitate any barium or strontium that may be in solution. In the example, portions of a standard Watts solution containing about 300 g/l of nickel sulphate about 60 g/l of nickel chloride and 40 g/l of boric acid were oxidized with hydrogen peroxide and the metal impurities precipitated therefrom by the addition of barium and strontium hydroxides and carbonates. In all cases the final pH was 5.2 and the temperature was either 55 DEG or 65 DEG C.