Sulphuric acid chalcopyrite leaching using ozone as oxidant

Among several effective oxidising agents which have been considered and tested for the acid oxidising leaching of chalcopyrite the application of ozone as gaseous oxidising agent showed very promising results. As the most important aspect has been estimated the fact, that the process is already very effective at room temperature so that the necessity of heating and cooling considerable quantities of dilute leach solutions can be avoided. In this paper the feasibility of direct oxidising leaching of chalcopyrite in a solution of sulphuric acid by using gaseous atmosphere containing ozone is studied. Special attention was paid to the contact time of the gas bubbles containing ozone in the leaching pulp with the aim to improve the leaching efficiency of the process. The results of the investigation reveal, that the extraction of copper into the solution increases with the height of the liquid column resp. the pulp volume as well as with ozone concentration in working atmosphere.