Copper Recovery from Copper Slag with Flotation Enhanced by Sodium Carbonate Synergistic Mechanical Activation

Flotation is one of the most important methods for recovering copper from copper slag, but the traditional grinding method realized the dissociation of the monomer the interface difference becomes smaller, 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 principle and experiment were conducted. With the influence of the addition of sodium carbonate on flotation, 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 clean the surface of mineral particles, slightly oxidizing the chalcocite surface and improving the flotation effect of copper slag. Under the optimal flotation conditions of 600 g/t sodium carbonate and 300g/t xanthate, the recovery efficiency of copper can reach 98.07% with a high concentration of 36.13%. Moreover, the flotation kinetic model of copper slag was established and the results show 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.