This study investigated the process of reclaiming Mo from calcined waste hydrotreating (CWHT) catalysts using tributyl phosphate (TBP) as an extractant with electron-withdrawing properties. Using inductively coupled plasma (ICP) technology, the optimal operating conditions for Mo recovery were determined based on the metal ion content in different processes. Considering the pH impact on metal species in solution, an acid leaching solution with 6 M sulfuric acid was employed. After 3 h of reaction, 94 wt% of the Mo was transferred from the WHT catalyst to the acid leaching solution. Adjusting the filtrate to a pH of 1.5 allowed the TBP to selectively extract over 98.8 wt% of Mo from the aqueous filter solution into the organic phase. MC-Cabe-Thiele theory predicts that a three-stage countercurrent extraction can reduce Mo to less than 0.2 wt%. Stripping moved approximately 98 wt% of the Mo from the organic to the inorganic phases. The recovered colorless organic tributyl phosphate can be used in the recycled extraction process.

Abstract
1. Introduction
2. Experimental Procedure
    2.1. Metal composition of waste hydrotreating catalyst
    2.2. Metal recovery experiment
    2.3. Analysis and characterization
3. Results and Discussion
    3.1. Acid leaching
    3.2. Organic extraction
    3.3. Stripping Mo species and regenerating TBP
    3.4. Process flow for extraction of Mo from wastecatalyst using TBP
4. Conclusion
Acknowledgement
References
Author Information

• Yongyang Bu(School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China)
• Haitao Wu(School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China)
• Kejie Hu(School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China)
• Dazhuang Huang(School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China, School of Graduate, University of Science and Technology Liaoning, Anshan 114051, China) Corresponding author
• Tian Ai(School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China)
• Songdong Yao(School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China) Corresponding author