Effect of calcium lignosulfonate on surface modification and bioleaching of chalcopyrite

Calcium lignosulfonate is a common anionic surfactant. In this study, calcium lignosulfonate (SL) was employed to modified chalcopyrite surface and promote chalcopyrite bioleaching. The bioleaching experiments revealed that in the absence of SL, the bioleaching rate of chalcopyrite was slower at the initial stage, and it was accelerated after a period of 12 days. Conversely, when SL was introduced during the bioleaching process, the bioleaching rate of chalcopyrite was a significant acceleration within the first 6 days. After the introduction of SL, the bioleach rate of chalcopyrite was about 3 times faster in the first 12 days. This highlights the effect of SL on expediting the bioleaching efficiency of chalcopyrite. Mechanism research indicates that after the introduction of SL, the adsorption energy of bacteria on mineral surface decreased from -2.71 to -4.37mJ/m2, the adhesion of bacterial was promoted. Further analysis through scanning electron microscopy, electrochemical analysis, and X-ray photoelectron spectroscopy demonstrates that after SL modification, the structure of jarosite on the chalcopyrite leaching residues became denser, and the relative content of Fe (III) and S (Ⅵ) was increased from 56.4% and 84.6% to 65.4% and 91.5%, respectively. These alterations are highly conducive to electron transfer processes and chalcopyrite oxidation.