Iodide Leaching Gold from Carbonaceous Refractory Gold Ores
Gold extraction using iodide leaching from refractory carbonaceous gold ores was studied.Thermodynamic analysis of iodide leaching chemistry had been carried out. Eh-pH diagram of Au-I2-I--H2O leaching system showed that the coordinating active forms from iodides were I3 and I-,while the major coordinate compound formed during iodide leaching was AuI-.For leaching parameters optimization, technological parameters such as I2 concentration, I2:I- ratio, oxidation assisting agents, liquid/solid ratio, and leaching duration were studied. The leaching results showed that the average Au leaching rate reached 91% and 92% for oxidized ore and roasted primary ore respectively. Leaching process proceeded in weekly acidic or neutral slurry at ambient temperature; the leaching duration was 4 hours. After that gold was extracted from the pregnant liquor by activated carbon adsorption desorption electrowinning process. Gold recovery was over 93% in the adsorption process, while the gold recovery in electrowinning process was about 95%,provided that the initial gold concentration is 40mg/L or larger.For iodine regeneration it is enough to add hydrogen peroxide in excess into the filtrate after gold electrowinning, all the iodides existing in the solution in any forms would be precipitated in the form of elemental iodine.
Gold extraction Carbonaceous gold ore Iodide leaching Leaching mechanism
G. C. Li S. C. Lu
The Graduate School, Heilongjiang Institute of Science and Technology, Harbin, China School of Civil and Environmental Engineering University of Science and Technology Beijing, Beijing,
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
3010-3015
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）