Effect of selected parameters on stibnite concentrates leaching by ozone

A novel leaching process for stibnite concentrates using ozone as oxidant has been studied in this paper. The main factors affecting the leaching rate such as leaching temperature, concentration of leaching agent, gas flow rate and liquid to solid ratio have been investigated comprehensively. In addition, the effect of ferric chloride and sodium chloride on antimony extraction has been studied. The results indicate that the leaching efficiency (%) of the antimony increases with the increase of those factors mentioned above. And the form that the antimony dissolves into solution is SbCln3 − n, while the sulfur mainly retains in the residue in the form of sulfur element. The oxidation leaching of stibnite concentrates has achieved antimony recoveries in excess of 99% under the optimum experimental conditions after 5 h of leaching.