Extraction of molybdenum as an added value in steel production
Byproduct recoveryRecycling and metallurgy
Chalmers tekniska högskola AB
Purpose and goal
The purpose of the work was to develop a hydrometallurgical process for the selective recovery of molybdenum from the steel industry’s dust. New samples were characterised, optimal parameters for selective leaching and extraction were determined. With the developed process, molybdenum can be leached with 90% yield with only 10% of the zinc content of the substance as contamination. In the extraction, molybdenum was then separated from zinc. Through process modeling with the McCabe-Thiel method, starting values for a scale-up to industrial scale were determined.
Structure and implementation
The project was divided into three stages. The first step involved careful physical and chemical characterisation of dust samples from the steel industry. In the second step, a selective leaching of molybdenum was designed and tested. Step 2 showed that molybdenum can be efficiently leached with a low concentration of hydroxide and that the liquid does not need to be heated. After leaching, molybdenum can be separated from contaminating metals, mainly zinc, with conventional liquid extraction. The results indicate a process with low environmental impact and cost.
The hydrometallurgical process for recovering molybdenum from the steel industry’s dust developed in the project can provide a significantly increased value of these dusts. With the process, molybdenum can be recycled selectively. Because molybdenum is considered to be one of the critical raw materials for the European metal industry based on limited reserves and environmental restrictions (environmental problems) during recovery, the use of domestic sources in the form of by-products may limit the dependence on imports of molybdenum and thereby support the metallurgical industry.