| 摘要 |
<p>The purpose of the present invention is to provide a neutralization method which attains a reduction in the amount of a costly, highly alkaline neutralizing agent to be used and renders efficient neutralization possible, when a barren liquid is neutralized, the barren liquid resulting from a treatment step for forming sulfides of nickel and cobalt from an aqueous sulfuric acid solution that contains nickel, cobalt, and one or more impurity metals comprising one or more of iron, magnesium, and manganese. This method comprises a first neutralization step (S11) in which a calcium carbonate slurry is added as a first neutralizing agent to the barren liquid to neutralize the barren liquid to an end point in the pH range of 5.0-6.0 and a second neutralization step (S12) in which the solution obtained in the first neutralization step (S11) is neutralized using a second neutralizing agent to obtain both a sediment containing the metals that remained in the barren liquid and a neutralized final liquid from which the metal ions have been removed.</p> |
