METHOD OF NICKEL EXTRACTION FROM SPENT CONCENTRATED SOLUTIONS OF ELECTROLESS AND ELECTRIC NICKEL PLATING Russian patent published in 1995 - IPC

FIELD: recovery and utilization of spent solutions of electroless and electric nickel plating. SUBSTANCE: concentrated spent solutions are reduced to nickel hydroxide with the use of alkali subsequent electroextraction of nickel at current density D_c=2-6 A/dm², D_A=3-9 A/dm², temperature of 20 to 60 C, pH = 4-5 in cathode sections, pH = 1-2 in anode section, pH = 8-9 in middle sections with hydroxide in an installation with titanium cathodes and lead anode. The installation is divided into five sections by means of canvas or chlorine diaphragms, two extreme sections are filled with a solution of nickel sulfate at a concentration of 250 g/l, boric acid - 25 g/l, sodium sulfate - 150 g/l, two-sections - with a solution of nickel sulfate - 250 g/l, boric acid - 25 g/l, sodiumsulfate - 150 g/l with excess nickel hydroxide sediment on the section bottom, central section - with a solution of nickel sulfate at a concentration of 250 f/l, boric acid - 25 g/l, sodium sulfate - 150 g/l, sulfuric acid. EFFECT: facilitated procedure. 1 tbl, 1 dwg