Copper recovery from copper slags through flotation enhanced by sodium carbonate synergistic mechanical activation

Flotation is one of the most important methods for recovering copper from copper slag, However, traditional grinding may be over grinding sometimes, resulting in smaller interface difference, which leads to a decrease in the selectivity of flotation. In this study, a sodium carbonate combined with mechanical activation enhanced flotation for recovering copper from copper slag was developed. Based on the phase analysis, the flotation experiment was conducted. It showed that adding sodium carbonate before wet grinding can change the surface energy of copper slag particles and increase the possibility of cracks between chalcocite particles and gangue particles, while sodium carbonate can also increase the Eh of the copper slag flotation system and improve the flotation effect. Under the optimal flotation conditions of 600 g/t sodium carbonate and 300 g/t xanthate, the recovery efficiency of copper can reach 98.07% with a concentration of 36.13%. Moreover, the flotation kinetic model of copper slag was established and the results showed that the movement of copper slag in the flotation process conforms to the first-order kinetics. The addition of sodium carbonate increased the stability of the pulp and improved the flotation kinetics greatly, resulting in a better flotation performance. [Display omitted] •The metal in copper slag was recovered by flotation.•Sodium carbonate and mechanical activation strengthen flotation.•The mechanism of activated flotation of copper slag was revealed.