Abstract

This article shows the treatment of the leaching solution by making a liquid-liquid dispersion with the diluent Massimo Sol with the aim of minimizing dissolved silica and suspended solids and studying the impact of this treatment on the solvent extraction of copper.

Materials and methods: The study on Shituru plants is a town in Likasi in the province of Haut-Katanga, Democratic Republic of Congo. The statistical methods of Taguchi and analysis of variance were used to process the experimental results, with a view to assessing, from a statistical and metallurgical point of view, the parameters influencing the yield of impurity removal from the leaching solution and the phase disengagement time on solvent extraction. Atomic absorption and optical emission spectroscopic methods coupled to an ICP - OES induced plasma were used to characterise the leaching solution sample in our study. The analyses revealed 4.00 g/L of copper and 0.70 g/L of cobalt for the metals in solution, and 845 ppm of dissolved silica and 1050 ppm of suspended solids for the impurities.

Results: For the solvent extraction tests, an orthogonal matrix 4 parameters with 4 levels was used to conduct these optimisation tests in order to evaluate the effect of the stirring speed (800 rpm, 1100 rpm, 1400 rpm and 1700 rpm), the ratio (0.8; 1.0; 1.2 and 1.4), contact time (120 seconds, 180 seconds, 240 seconds and 300 seconds) and percentage of extracting in the organic phase (15, 20, 25 and 30) on the extraction of copper from the leach solution by the organic phase. These tests to optimize the copper solvent extraction operation gave the results for the operating conditions of the controllable parameters: stirring speed of 1700 rpm, ratio of 1.4, and contact time of 180 seconds and percentage of extracting of 20% in the organic phase. The confirmation test under optimum conditions gave a copper recovery yield of 92.44% and a phase disengagement time of 95.17 seconds.

Conclusion: Confirmation tests were carried out under the optimum conditions obtained in order to confirm the results obtained. Removal efficiencies of 66.02% and 75.99% were obtained for dissolved silica and suspended solids content respectively, a phase disengagement time of 50.02 seconds and a copper recovery efficiency of 96.77% at solvent extraction.