Extraction of Molybdenum from Spent HDS Catalyst by Pressure Alkaline Leaching

Molybdenum bearing spent hydrodesulphurization (HDS) catalyst is an important secondary resource. In the present research, the extraction of molybdenum from the roasted spent HDS catalyst was investigated by pressure alkaline leaching using NaOH and Na2CO3, respectively. The process of pressure leaching using Na2CO3 solution was characterized by high extraction of molybdenum, lower aluminum leaching, as well as low cost of mineral decomposition, which make it become the better option. For the process of pressure leaching using Na2CO3, under the optimum conditions of 20 wt% Na2CO3 addition, leaching at 170 °C for 30 min with a liquid/solid ratio of 2 mL/g, the leaching of molybdenum reached 95.4%, and the leaching of aluminum was only 0.7%.