Characterization of solute transport parameters in leach ore: inverse modeling based on column experiments

Abstract

Heap leaching is essentially a process in which metals are extracted from mine ores with lixiant. For a better understanding and modeling of this process, solute transport parameters are required to characterize the solute transport system of the leach heap. For porous media like leach ores, which contain substantial gravelly particles and have a broad range of particle size distributions, traditional small-scale laboratory experimental apparatus is not appropriate. In this paper, a 2.44 m long, 0.3 m inner diameter column was used for tracer test with boron as the tracer. Tracer tests were conducted for 2 bulk densities (1.92 and 1.62 g/cm³) and 2 irrigation rates (2 and 5 L/ (m²·h^-1)). Inverse modeling with two-region transport model using computer code CXTFIT was conducted based on the measured breakthrough curves to estimate the transport parameters. Fitting was focused on three parameters: dispersion coefficient D, partition coefficient β, and mass transfer coefficient ω. The results turned out to fall within reasonable ranges. Sensitivity analysis was conducted for the three parameters and showed that the order of sensitivity is β>ω>D. In addition, scaling of these parameters was discussed and applied to a real scale heap leach to predict the tracer breakthrough.

Keywords

leach ore / tracer test / inverse modeling / parameter up-scaling

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Acknowledgements

This research was funded by GeoSystems Analysis, Inc., USA and the Key Laboratory of Water and Sediment Sciences, MOE, China. Thank GeoSystems Analysis for providing the laboratory experimental data. Thank the assistance from the laboratory staff Aaron Graham, Mike Yao, and Joe Wade. Mike Milczarek provided valuable review, which is greatly appreciated by the author.

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2014 Higher Education Press and Springer-Verlag Berlin Heidelberg