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.

摘要

强制通风是强化生物堆浸的有效措施. 为了揭示不同喷淋速率与通风强度组合对硫化铜矿生物浸出的影响, 利用 COMSOL 进行了数值模拟. 结果表明, 通风后堆底氧气浓度最高, 气流以通风管道为中心向边坡作球形扩散, 且水平扩散距离大于竖直距离. 当喷淋速度-通风强度比较高时, 堆场平均温度主要由通风强度控制; 较低时则是矿物反应热、 溶浸液携带热量及气流携带热量三者的平衡结果. 当通风强度高于 0.90 m³/(m²·h)时, 氧气不再成为矿物溶解的限制性因素. 此外, 若氧气供应充足, 低喷淋速率时堆底 Cu 回收率较高, 而高喷淋速率时矿堆中上部 Cu 回收率较高. 数值模拟揭示了硫化铜矿生物堆浸过程中一些动力学及热力学规律.