Electroosmotic drainage, a pilot application for extracting trapped capillary liquid in copper leaching

• Electroosmotic drainage was applied to solid residues from leaching copper.
• Experiments were conducted employing 1-cubic-meter tanks.
• Electrode configuration, voltage applied, electrode distance, polarity and intermittency were studied.
• Alternate linear configuration with intermittency in applied voltage provided the best results.

Electroosmotic drainage tests were carried out using one-cubic-meter tanks filled with solid residues from leaching copper. The main objective was to evaluate the efficiency of this technique for the removal of capillary-entrapped solution as a function of the following parameters or operational variables: electrode configuration, voltage applied, distance between electrodes, polarity reversal and intermittency of the applied voltage. The efficiency of this technique was compared to that of drainage by gravity, based on three indicators: moisture reduction, energy consumption per cubic meter of drained solution and drainage time factor, which allows a visualization of the reduction of drainage time in relation to natural drainage time by applying electroosmotic drainage. Of the three tested electrode configurations, hexagonal, linear and alternate linear, the last configuration with intermittency in applied voltage (12 V) and a distance of 0.6 m between electrodes gave the best results, with a moisture reduction of 2.02, an energy consumption of 6.7 kWh/m3 and a drainage time factor of 6.45. Considering these results, it is demonstrated that the technology increases the spatial capacity of copper leaching and reduces the weight of the material to be transported.