METHOD OF PRODUCING NICKEL SULFATE

摘要

PROBLEM TO BE SOLVED: To provide a method of producing nickel sulfate containing thiosulfuric acid.SOLUTION: The method of producing nickel sulfate is provided that comprise a pressurization leaching step in which raw material slurry containing a nickel sulfide is supplied to an autoclave and leached with sulfuric acid under high temperature and high pressure to obtain an aqueous solution of nickel sulfate as a leachate. In the pressurization leaching step, the leaching conditions are adjusted so that an oxidation reduction potential (silver/silver chloride electrode) of the leachate is 480 mv or less. Since an ORP (Oxidation Reduction Potential) of the leachate is 480 mv or less, a part of sulfur in the nickel sulfide becomes a thiosulfuric acid ion without being oxydized to a sulfuric acid ion. Nickel sulfate including thiosulfuric acid is therefore obtained.SELECTED DRAWING: Figure 1