Simultaneous sulfide oxidation and gold dissolution by cyanide-free leaching from refractory and double refractory gold concentrates

Pyrite and arsenopyrite are known to be the most common gold-bearing sulfide minerals in refractory gold ores. Traditionally, these have been first oxidized by roasting, acidic pressure oxidation or bio-oxidation release gold, after which is dissolved subsequent cyanide leaching step. The chloride (chloride-bromide) solution presents an alternative cyanide-free media, able not only leach minerals, but also a single unit process. Therefore, current study investigation of simultaneous from (sulfidic) double (sulfidic preg-robbing) concentrates. results show that extraction investigated concentrate was linearly dependent on oxidation: 97% resulting 99% extraction, 67% 81% 46% extraction. However, with concentrate, as low 18% despite ([Cl-]aq,0 = 6.3 mol/L, [Br-]aq,0 1.0 [Cu2+]aq,0 1.6 mol/L). In order mitigate challenges related losses due preg-robbing, active carbon (CICl) well addition lead nitrate were investigated. With CICl, recovery could increased significantly (67%). Further, CICl shown improve substantially (88%). shows presented approach can address nature concentrates atmospheric - process providing new horizons for future utilization