Neutralization method and neutralization plant

摘要

The purpose of the present invention is to provide a hydrometallurgical method for nickel oxide ore, with which it is possible to improve the filtering characteristics in a dezincification step in which a neutralized liquid that contains zinc besides nickel and cobalt is sulfided and the formed zinc sulfide is separated, and to prolong the life of the filter cloth. This method includes the step of neutralizing a leachate in a neutralization tank (11), the step of adding a coagulant to the neutralized slurry and separating the slurry into neutralized sediment and a neutralized liquid, the step of measuring the viscosity of the neutralized liquid, the step of temporarily storing the neutralized liquid in a storage tank, and the step of transferring the stored neutralized liquid to a dezincification tank (31) for a dezincification step S4 that follows the neutralization step S3. In the case where the measured viscosity of the neutralized liquid is higher than 0.10 sec/cm