METHOD FOR NEUTRALIZING SULFURIC ACID ACIDIC SOLUTION AND HYDROMETALLURGICAL METHOD FOR NICKEL OXIDE ORE

摘要

Provided are: a sulphuric acid acidic solution neutralisation method by which the pH of a neutralised solution can be stabilised; and a nickel oxide ore hydrometallurgical method. The present invention comprises: a sulphuric acid leaching step in which an ore slurry of nickel oxide ore is sulphuric acid leached; a neutralisation step in which neutralisation is performed by adding a neutralising agent to a crude nickel sulphate aqueous solution; and a dezincification step in which zinc is removed as zinc sulphide by adding a sulphurising agent to the neutralised solution. In the neutralisation step, the addition amount of the neutralising agent is adjusted using a neutralising agent addition ratio as an index, said neutralising agent addition ratio indicating the addition amount of the neutralising agent relative to the amount of free sulphuric acid in the crude nickel sulphate aqueous solution. It is possible to prevent insufficient addition and excessive addition of the neutralising agent and stabilise the pH of the neutralised solution without changing the temperature of the solution and without a pH meter being affected by a neutralised sediment. In the dezincification step, it is possible to maintain the zinc removal efficiency and the solid-liquid separation efficiency.