OPERATING METHOD IN HYDROMETALLURGY OF NICKEL OXIDE ORE

摘要

It is an object to provide a method for producing magnesium oxide by which magnesium oxide being high in purity and low in impurity content can be produced simply and efficiently from a sulfuric acid solution containing magnesium and calcium such as waste water. In the present invention, calcium is precipitated as calcium sulfate and separated by concentrating a sulfuric acid solution containing magnesium and calcium, and magnesium is precipitated as magnesium sulfate and separated by further concentrating the solution resulting from the separation of calcium. The separated magnesium sulfate is roasted together with a reductant, so that magnesium oxide and sulfur dioxide are obtained. The resulting magnesium oxide is washed to produce magnesium oxide with high purity.

主权项

1. An operating method in hydrometallurgy of nickel oxide ore comprising a leaching step of adding sulfuric acid to a slurry of nickel oxide ore to leach the ore under high temperature and pressure conditions, a solid-liquid separation step of separating a leach residue to obtain a leachate, a neutralization step of adding a neutralizing agent to the leachate and separating a neutralized precipitate containing the impurity to obtain a neutralization final liquid containing nickel and cobalt, and a sulfurization step of subjecting the neutralization final liquid to sulfurization treatment to obtain sulfide and barren liquor containing nickel and cobalt, wherein
a magnesium oxide that was obtained in the magnesium oxide production step is used as the neutralizing agent that is added in the neutralization step in the hydrometallurgy of the nickel oxide ore, wherein the magnesium oxide production step comprising: a calcium separation step of precipitating as calcium sulfate and separating the calcium contained in the barren liquor by concentrating the barren liquor obtained in the sulfurization step; a magnesium crystallization step of precipitating as magnesium sulfate and separating the magnesium contained in the solution obtained via the calcium separation step by further concentrating the solution; a roasting step of obtaining magnesium oxide and sulfur dioxide by roasting the magnesium sulfate separated in the magnesium crystallization step together with a reductant; and a washing step of washing the magnesium oxide obtained in the roasting step is used as neutralizing agent that is added in the neutralization step in the hydrometallurgy of the nickel oxide ore.