Hydrometallurgical process for nickel oxide ore

摘要

A method for the wet-smelting of nickel oxide ore by high pressure acid leach, wherein a high iron oxidation ratio is achieved in order to fix most of iron in a leach residue in the form of hematite, the amount of sulfuric acid used during leaching is minimized, and nickel and cobalt are leached out at a high leach rate. The flow rate and the carbon grade of ore slurry prepared in a first step are measured, and the amount of carbon charged in a second step is determined. The blow ratio of high-pressure air and high-pressure oxygen is subsequently adjusted so that the oxygen purity thereof is 21—60% in a second step for adding sulfuric acid and performing a leaching process by using high-pressure air and high-pressure water vapor, the oxygen blow rate is set to 200—600 Nm