Up to now, many nickel production methods have been researched and industrialized, and the hydrometallurgical process of copper-nickel matte has been studied for many years. Hydrometallurgy of copper-nickel matte includes several treatment methods such as selective sulfuric acid leaching, oxygen-ammonia leaching, chlorine leaching, etc. Among them, selective sulfuric acid leaching which consists of atmospheric pressure leaching and pressure leaching has been most widely used.
However, selective sulfuric acid leaching process consisting of single stage atmospheric pressure leaching followed by pressure leaching is regarded to be ineffective for copper-nickel matte with low Cu and high Ni content.
Cha Su Gyong, a section head at the Faculty of Metallic Engineering, has proposed a 3-stage counter-current selective leaching for improving nickel leaching efficiency and copper separation efficiency of copper-nickel matte with high Ni/Cu ratio by increasing the stage number of atmospheric pressure leaching, and investigated the effects of factors such as temperature, leaching time, oxygen pressure, etc. on nickel leaching efficiency and copper separation efficiency, based on the mineralogical and metallurgical analysis of the matte.
The total nickel leaching rate determined through atmospheric pressure and high-pressure leaching experiments reaches 92.18%.