Effect of Oxidative Roasting and Grinding on Sulfuric Acid Leaching Efficiency of Nickel and Aluminum from Alkaline Leaching Residue of Spent Hydrodesulphurization Catalysts

Abstract

Spent hydrodesulphurization (HDS) catalysts are treated with hydrometallurgical leaching processes such as caustic leaching and acid leaching with roasting as a pre-treatment step. In the alkaline leaching processes such as sodium carbonate roasting followed by water leaching, most of the molybdenum and vanadium are selectively leached and most of nickel is left in the residue after the alkaline leaching of spent HDS catalysts. Therefore, it is important to recover nickel from the residue. The main form of nickel in the residue is spinel, therefore, it is difficult to extract nickel from the residue using mineral acids.