Minimization of Organic-in-Aqueous (O-in-A) Entrainments and Improvement of Solvent Extraction Efficiency by Optimizing Key Parameters Using Response Surface Methodology (RSM)

Physico-chemical treatment is the best technology for the purification of pregnant leach solutions (PLS) from copper–cobalt slurry because of its ability to separate the desired metallic ion from other ions contained in the PLS. This work investigated the batch solvent extraction (SX) of solutions from copper-cobalt slurry using MEXTRAL 984N. The continuity of two phases including the organic and aqueous phases was studied separately to optimize the SX key parameters such as the organic phase/aqueous phase (O/A) ratio (from 1 to 2) and the contact time of the organic and aqueous phases (from 2 to 5 min). The results of the experiments carried out in the laboratory showed the organic continuity was favorable for the extraction at a ratio of 1 and at contact time of 4 min and for the stripping at ratio of 1 and the contact time ranging from 4 to 5 min with an efficiency of 95.57 and 76.46% for the extraction and stripping respectively and organic entrainment of 0.53 and 0.3% for the extraction and stripping respectively, while for the same operational conditions in aqueous continuity, the efficiency was 92 and 72% for the extraction and stripping respectively and the organic entrainment of 0.57 and 1.5% for the extraction and stripping, respectively.