Experimental study on microbubble air oxidation acid leaching pre-removal of metals from copper anode slime

To address the issues of impurity introduction by oxidants and low conventional air oxidation rates in traditional copper pre-removal processes from copper anode slime, a microbubble air oxidation-enhanced acid leaching technology was proposed. This study focused on 2 types of copper anode slimes（YJN-1 and YJN-2） using dilute sulfuric acid and copper-rich solution as leaching agents. The leaching behaviors of copper, selenium, tellurium, and silver under microbubble air oxidation conditions were systematically investigated in a self-made microbubble reactor. The results show that under the conditions of 85 ℃ and a solid-to-liquid ratio of 5∶1, the dilute sulfuric acid system exhibited a regular leaching effect. After 3 hours of reaction, the copper removal rates from both types of anode slime exceeded 94 %, with partial leaching of tellurium and silver achieved, while selenium was almost not leached, indicating preliminary separation of the metals. In contrast, the copper-rich solution system, which has a complex composition, showed poor leaching regularity and unsatisfactory copper removal efficiency. The microbubble air oxidation technology creates favorable conditions for the subsequent recovery of precious metals and has promising industrial application prospects.