IRON REMOVAL METHOD OF CRUDE NICKEL SULFATE SOLUTION

摘要

PROBLEM TO BE SOLVED: To provide an iron removal method of a crude nickel sulfate capable of minimizing use of chemicals necessary for an oxidation neutralization treatment and acid-dissolving of a nickel precipitate in a once generated iron removal precipitate and capable of reducing a nickel loss in an iron removal step without requiring a new facility.SOLUTION: An iron removal method is provided which comprises adding calcium hydroxide to a crude nickel sulfate solution given by dissolving a lead removal precipitate containing impurities to thereby remove impurities as a precipitate. In accordance with an iron concentration in the crude nickel sulfate solution, calcium hydroxide is added. When the iron concentration in the crude nickel sulfate solution is 0.5 g/L or less, calcium hydroxide is added in such an amount that a final pH given at the time the precipitate is generated ranges from 4.2 to 5.0. A target product of the crude nickel sulfate solution is any of electric nickel, electric cobalt, nickel sulfate pure liquid and nickel sulfate crystal. The crude nickel sulfate solution is treated a wet-type refinery process including a solvent extraction step and a COB-SX step (S500).SELECTED DRAWING: Figure 3