Numerical analysis of aerated heap bioleaching with variable irrigation and aeration combinations

Abstract

Forced aeration is an effective way to accelerate the heap bioleaching process. To reveal the effects of different irrigation and aeration combinations on bioleaching performance of copper sulfides, numerical simulations with Comsol were carried out. Results showed the oxygen concentration is the highest at the bottom with forced aeration, the airflow transports spherically from the aeration pipeline to the slope, and the horizontal diffusion distance is further than vertical value. When the irrigation-to-aeration ratio is higher, the average heap temperatures are mainly decided by aeration rates; otherwise, temperature distributions are the equilibrium of mineral reaction heat, the livixiant driven heat and the airflow driven heat. When the aeration rate is higher than 0.90 m³/(m²·h), oxygen concentration is no longer a limiting factor for mineral dissolution. Additionally, on the premise of sufficient oxygen supply, Cu recovery rate is higher at the bottom with low irrigation rate; while it is higher at upper regions with high irrigation rate. The numerical analysis uncovered some insights into the dynamics and thermodynamics rules in bioleaching of copper sulfides with forced aeration.

Keywords

forced aeration / irrigation-to-aeration ratio / oxygen concentration / temperature distribution / copper leaching rate

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