Modelling the scale-up of the iodine-assisted chalcopyrite leaching in ferric sulfate media from reactors to columns and simulating heap operations

Abstract

The iodine-assisted heap leaching of chalcopyrite involves the addition of iodide in ferric sulfate media to accelerate the dissolution of chalcopyrite at ambient temperature. The previous studies using reactor leaching tests identified the solution potential, the amount of iodide added, and temperature as the factors controlling the process performance. In the present study, the iodine-assisted chalcopyrite leaching process was scaled up from reactors to 1-m and 6-m columns to further understand how these parameters control the process performance at a larger scale. This is essential to optimize the process in industrial-scale heap leach pads. The HeapSim-2D model was calibrated with the 1-m and 6-m column leach tests together with the kinetic parameter values obtained in the previous reactor leaching tests. When the iodine-assisted chalcopyrite leaching was scaled up from reactors to 1-m and 6-m columns, the leaching became slower because the ore used in the column leaching tests had larger particle sizes with partially-liberated chalcopyrite particles. The calibrated model was then used to carry out the sensitivity analyses to assess the response of the process performance to key design and operating variables, including irrigation rate, ferric concentration, total iodide concentration, temperature, and heap height. The analyses show that the copper extraction could be optimized by adjusting these key design and operating parameters.