Mixing and Oxygen Transfer in Mineral Bioleaching

Author:

Graham M. Fraser

This paper explores the role of mixing and oxygen transfer in mineral bioleaching reactors, emphasizing how agitator and impeller design affect process efficiency. It compares various impeller types, such as the LIGHTNIN A315 and Rushton turbine, in maintaining solids suspension, gas dispersion, and optimal oxygen uptake. The study concludes that improved mixing design enhances bacterial oxidation, heat and mass transfer, and overall biooxidation reactor performance.

Key Learnings

• Efficient mixing and oxygen transfer are critical for maximizing bacterial activity and metal recovery in bioleaching reactors.
• Impeller and agitator design directly influence gas dispersion, solids suspension, and oxygen distribution.
• The LIGHTNIN A315 impeller provides better oxygen transfer and mixing uniformity compared to traditional Rushton turbines.
• Proper control of shear rates ensures bacterial health while maintaining effective mass transfer.
• Consistent temperature and pH through uniform mixing enhance biooxidation process stability.
• Reactor scale-up requires balancing power input, gas flow, and impeller geometry for optimal performance.
• Improved mixing design leads to higher bioleaching efficiency, reduced energy consumption, and better process control.
• Understanding hydrodynamic behavior in gas-liquid-solid systems is essential for designing reliable biooxidation reactors.