Thermal treatment of Lanxess Lewatit® AF 5 resin used in the atmospheric chalcopyrite leaching process: Regeneration and sulfur recovery

Abstract

Elemental sulfur is a key component in the acidic Albion chalcopyrite atmospheric leaching process and is a challenging issue in the residue. It has been proposed to use Lanxess Lewatit® AF 5 (AF 5) catalyst during the leaching of copper concentrates in the acidic Albion leach process, to eliminate the elemental sulfur from the leach residue. When using AF 5 during leaching, the copper and the iron recoveries were above 95% and 80%, respectively. The AF 5 collected 100% of the elemental sulfur and for a 1:1 ratio of AF 5 to concentrate, the loaded AF 5 gained 12.3 wt% sulfur after the first acidic Albion leach test and contained 24.3 wt% sulfur after two leaching tests.In this study, the optimum conditions for the removal of sulfur from the catalyst were investigated using a high temperature process in a laboratory tube furnace. The results indicated that the maximum desulfurization of 90.1% was achieved at 550 °C after 10 min. The regenerated AF 5 could be reused for several chalcopyrite leaching-AF 5 cycles. For the recycled AF 5, the sulfur absorption decreased by only 1.0% while the recoveries of copper and iron were not affected. The kinetic study showed that the activation energy for AF 5 desulfurization was 164.5 kJ/mol;