| 摘要 |
PURPOSE: A method for preparing nickel sulfate crystal with a high degree of purity by using waste nickel anode is provided which removes impurities without washing the nickel sulfate crystal several times and effectively prepares nickel sulfate crystal with high degree of purity . CONSTITUTION: The method comprises steps of: (i) processing waste nickel anode to prepare nickel chip; (ii) dissolving the nickel chip in a mixture of sulfuric acid and an oxidizing agent, wherein an equivalent ratio of the sulfuric acid and the oxidizing agent per 1 equivalent of the waste nickel is 1:0.5-1:1.5, to extract nickel; (iii) evaporating, concentrating, cooling and filtering the obtained nickel extract to prepare primary nickel sulfuric acid crystal; (iv) after washing the surface of the primary crystal and re-dissolving it, adding the oxidant thereto to oxidize Fe2+ into Fe3+; (v) by pouring nickel carbonate or nickel hydroxide with high degree of purity into the solution of the step (iv) to adjust solution pH to 3-6, forming sludge of hydrated iron; (vi) filtering the solution to remove the sludge of hydrated iron and impurities from the solution; (vii) evaporating, concentrating and crystallizing the impurities removed nickel sulfate solution to prepare nickel sulfate crystal; and (viii) drying the prepared crystal. |
