Method for producing high-purity nickel sulfate and method for removing impurity element from solution containing nickel

摘要

Provided are an impurity-element removing method for selectively removing magnesium from a nickel-containing solution, and a method for producing high-purity nickel sulfate using the impurity-element removing method. The production method includes a production process in the production method of producing high-purity nickel sulfate from a nickel-containing solution, and the nickel-containing solution in the production process is subjected to an impurity-element removal treatment that includes: a hydroxylation step of adding an alkali hydroxide to the nickel-containing solution in the production process to form a hydroxylated slurry; a carbonation step of adding an alkali carbonate to the hydroxylated slurry to form a carbonated slurry, and recovering nickel component from the solution; a solid-liquid separation step for the slurry thus obtained; and a neutralization step of subjecting a solution after reaction obtained by solid-liquid separation to a neutralization, and recovering an impurity element included in the nickel-containing solution in the production process.

主权项

1. A method for producing a mixed precipitate of nickel hydroxide and nickel carbonate useful in the production of high-purity nickel sulfate; the method comprising:
providing an acidic sulfuric acid solution containing nickel, the acidic sulfuric acid solution containing nickel being subjected to the following steps in order: a hydroxylation step of adding an alkali hydroxide to a portion of the acidic sulfuric acid solution containing nickel, providing a pH range of 7.5 to 7.8 and, forming a hydroxylated slurry that includes a precipitate of nickel hydroxide and a solution after hydroxylation, the solution after hydroxylation containing a portion of nickel which did not form the precipitate of nickel hydroxide; a carbonation step of adding an alkali carbonate to the hydroxylated slurry, providing a pH range of 7.7 to 8.0, and carbonating the portion of nickel in the solution after hydroxylation, and forming a mixed slurry that includes the precipitate of nickel carbonate, the precipitate of nickel hydroxide, and a solution after carbonation; wherein the mixed slurry includes a mixed precipitate of nickel hydroxide and nickel carbonate, and the solution after carbonation; a solid-liquid separation step of separating the mixed slurry into the mixed precipitate of nickel hydroxide and nickel carbonate, and the solution after carbonation; and a neutralization step of subjecting the solution after carbonation to a neutralization treatment at a pH range of 8.0 to 8.5 to produce a neutralized solution including a neutralized precipitate containing an impurity element and a solution after neutralization, and subjecting the neutralized solution to solid-liquid separation to recover the impurity element included in the solution after reaction as the neutralized precipitate containing the impurity element.