Heap and dump bioleaching are operational units with physical, chemical, mineralogical and microbiological processes, which are interconnected at different scales. Consequently, in the search to understand and optimize these processes it is impossible to approach intuitively and therefore, it is necessary to systematically integrate knowledge by means of phenomenological modelling. During several years, BioSigma has developed a phenomenological model that accurately predicts the performance of its technologies applied in the bioleaching of heaps and dumps, in terms of copper recovery and other important biohydrometallurgical parameters such as acid consumption and iron recovery. The model is one-dimensional in liquid and gas flow, and includes kinetic laws for primary and secondary sulphides, copper oxides, pyrite and gangue minerals. The model also includes transport of ionic species and microorganisms, chemical speciation, attachment/detachment and growth of iron- and sulphur-oxidizing microorganisms, oxygen balances in liquid and gas phases and heat conservation. The model allows the user to find reaction parameters by means of automatic calibration with experimental results. The heap bioleaching model was successfully calibrated and validated using experimental data from tests made in columns and heaps, and it is capable of reproduce and predicts the most important process variables. The model is currently used industrially to assess heap/dump bioleaching performance on different industrial projects and scenarios, including the effect of mineralogy, particle size distribution, irrigation rate, microbial addition, heap height, aeration rate, temperature of the irrigated solution, and the application of anti-evaporation film among others. In conclusion, BioSigma have developed a state of the art tool which is available to be used by the industry to improve copper extraction operations.
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