Dezincification plant, method for operating dezincification plant, and hydrometallurgical method for nickel oxide ore

摘要

The purpose of the present invention is to provide a hydrometallurgical method for nickel oxide ore, in which the plant can be smoothly started after completion of a periodic inspection because zinc sulfide separation imposes no load on the filter cloth and it is possible to reduce the amount of zinc remaining in a mother liquor (dezinced liquid) for nickel recovery to 1 mg/L or less. In the invention, after completion of a periodic inspection, the plant is started up in the following manner. In the beginning of the start-up, the neutralized liquid is not sulfided, and a switching valve (39) in feed piping (34) is switched so that the neutralized liquid is circulated to a dezincification tank (31) through circulatory piping (38). When the flow rate and/or temperature of the neutralized liquid being circulating has reached a given value or higher, the neutralized liquid is sulfided in the dezincification tank to yield a mother liquor for nickel recovery that contains zinc sulfide. The switching valve (39) is switched to transfer the zinc sulfide-containing mother liquor for nickel recovery to a filter device (33) through transfer piping (37).