Bstudy On Gold Extraction Technology Of Carbon-in-leach Process From The Fine And Low Grade Gold Ore Of Zijinshan Gold Mine

In recent years CIL has been used widely all over the world, for it has such advantages as strong adaptability, simple process, high gold recovery rate and environmental protection benefit. In this dissertation, researches on CIL process of the -0.074mm grade fine mud of Zijinshan Gold Mine were performed, including the concentration of sodium cyanide, cyanide, lime dosage, time and activated carbon adsorption time and dosage, the copper leaching, the activated carbon adsorption were studied, and research were studied on engineering practice on the basis of experiment. Aiming at the problem of low adsorption properties of the active carbon, it were studied by the microscope, MLA and some other research methods.Experiments show that, CIL technology was suitable for processing -0.074mm grain fine mud of Zijinshan Gold Mine. The best conditions were:the concentration of sodium cyanide 0.02%, pH 10.5,36 hours cyaniding time, then the gold leaching rate was 94.64%; the new carbon has high adsorption performance than the old carbon, when the new carbon density was 25g/l, the adsorption rate was 100%, while the old carbon density was 80g/l, the gold adsorption rate was only 94.5%.That scene flow tests show that:the CIL production index is ideal, gold leaching rate was 91-92%, copper leaching rate was about 30%, the adsorption rate of gold and copper was more than 98% and 99%.The main problem was too much carbon density in the CIL system,bring about the backlog of metal was high. The content of calcium, copper in active carbon were the main factors affecting its performance. By fire regeneration the activated carbon iodine value and the performance of activated carbon can improve more than by acid regeneration.In the active carbon, the adsorption of copper was affected by the concentration of sodium cyanide, alkalinity and other factors.Studies showed that carbon surface and surface layer, shallow pores were covered or filled by calcite, and from the inside to the outside the calcite content increased, the coppers were adsorbed in carbon empty pore and non porous parts. So the reason of carbon contain calcium was the formation of calcite, and also the reason of carbon performance decreased was the formation of calcite.