LAUSR

Abstract The present study investigated the electrocoagulation (EC) process using holed Ferrum electrodes (HFE) in the mineral industries for copper recovery from the pregnant leach solution (PLS). To this end, the response surface methodology was used to optimize factors affecting copper recovery in the EC process. The Box-Behnken design was employed to optimize experiments and effects of four independent variables - including initial pH (X1), current density (X2), electrode distance (X3), and electrolysis time (X4) - were studied to investigate copper recovery. Moreover, a linear model was used to calculate the copper recovery rate. The most important independent variables and their interaction were evaluated using ANOVA. Optimal operating conditions with copper recovery were obtained at the initial pH of 5.2, current density of 438.2 mA/cm2, electrode distance of 2.10 cm, and electrolysis time of 68.05 min. The copper grade yield was above 90% that was shown by XRD and SEM-EDAX analyses. The results of the SEM-EDAX analysis indicated that the main elements contained in particles included copper (82.5%–90.4%), Fe (6.2%–8.6%), and O2 (3.4%–8.9%), respectively. Moreover, the results of XRD studies confirmed that the minerals formed in the studied samples were mostly classified into two main phases of copper and cuprite, and that the rare phase included quartz minerals. It is concluded that the EC process as a reliable method has highly desirable capability in the recovery of soluble copper and recycling of water from mineral industries, especially in mineral processing plants.