Deep purification of Nickel Sulfate solution produced by Ni-electroplating sludge recycling process

Using Nickel saponified P507 purify the Nickel Sulfate Solution produced by Ni-electroplating sludge sulfuric acid leaching solution recycling process. Study the method of one step Ni²⁺ saponification P507, respectively in which the effect of pH, phase ratio, reaction time and temperature on extraction were investigated, the effect of sulfur concentrate on tripping was studied. The result shows that under the following optimum conditions, that is, using 10% P507(volume fraction) plus sulphonated kerosene as the extractant, Nickel saponification rate is 80%, pH=2.2, V_O/V_A=1/8, in 30 ℃ and reaction time is 5 min, the concentrate of Fe³⁺ ion can be decreased close to 40 mg.L^-1 after a six-stage counter current extraction. After iron removal process the Nickel sulfate solution can be deep purified under the following optimum conditions, that is, 80% saponification rate, pH=3.3, V_O/V_A=1/8, in 30 ℃ and reaction time is 5 min, after a four-stage counter current extraction the concentrate of the rest impurity ions can be decreased to reach the range of deep purification standard. The purification loaded organic can be stripped using 4 mol.L^-1 H₂SO₄ solution under the following condition: V_O/V_A=5/1, in 30 ℃ and reaction time is 5 mins, after a four-stage counter current stripping the organic phase can be reused. The tripping liquor can be reused by the stage of electroplating sludge leaching.