| Recently rational, efficient and environment friendly exploitation and utilization of the refractory gold mineral resource have become the main challenge faced by every gold-producing country in the world. In this dissertation, researches on treatment of two kinds of refractory gold concentrates, high copper carbon-bearing and arsenic-bearing gold concentrates, were performed, including strengthening leaching of high copper carbon-bearing gold concentrate with leaching-aid reagent, comprehensive flotation recovery of cyanidation tailing, electrochemical study of biooxidation of arsenopyrite, leaching kinetic study of biooxidation of arsenic-bearing gold concentration and biooxidation-cyanidation of high carbon arsenic-bearing gold concentrate, and the technology extension and industrialization practice were conducted on the base of the fundamental researches.The effects of grinding size, leaching time, concentration of sodium cyanide, dissolved oxygen concentration and amount of lead oxide on the gold leaching and consumption of sodium cyanide were investigated in the study of direct cyanidation of the high copper carbon-bearing gold concentrate (Cu2.28%). For the conventional leaching,89.48%gold leached and15.58kg/t sodium cyanide consumed in72h. However for the strengthening leaching,98.08%gold leached and5.60kg/t sodium cyanide consumed in48h with20mg/L dissolved oxygen and4kg/t PbO. The results showed that when the high copper carbon-bearing gold concentrate was leached with addition of enriched oxygen and PbO, the dissolution of copper and the adsorption of carbon to the leached gold were inhibited, the consumption of sodium cyanide consumption was reduced and the gold leaching was enhanced.with the consideration of zero waste water diacharge, the polymetallic sulfide cyanidation tailing was treated by the technical route of bulk flotation-separation of copper and lead-separation of lead and zinc, the copper, lead and zinc were recovered comprehensively. The results showed that the cyanide and the calcium oxide concentration decreased rapidly in the flotation of cyanidation tailing with barren solution, keeping the steady concentration of these two reagents was good for the flotation of the metal sulfide minerals. According to the effect of every heavy metal ions and their complexes on the flotation of desired minerals, the proper reagent system and process flow were adopted, and the selective flotation of lead was easily achieved in the separation of copper and lead or lead and zinc.The optimal growth temperature, pH value and the toxic ions resistance of the TCJ mixed culture were investigated, the results indicated the culture could grow under the temperature from33to45℃and pH value from0.8to1.8, with the optimal temperature40℃and pH1.5, and could resist the toxic ions, Cu, Cl-and As3+up to10g/L,5g/L and3g/L respectively. The TCJ culture was adapted to the high concentrations of chloride and arsenic ions by gradually increasing the concentrations of these two ions in the slurry. The critical concentrations of chloride and arsenic ions for efficient biooxidation of gold concentrate were2.7g/L and15g/L respectively. After adaption, the culture could efficiently treat arsenic-bearing gold concentrate containing arsenic no more than12%, its activity and toxicity resistance of the culture were improved, and was suitable for the industrialization practice of biooxidation of arsenic-bearing gold concentrates.The oxidation mechanism and the electrochemical kinetic of arsenopyrite with or without bacteria and leaching kinetic were investigated by linear scanning electrochemical measurement technology. The research showed that the bacteria enhanced the cathodic process and the galvanic effect between arsenopyrite and other sulfide minerals, accelerated the dissolution of intermediate products and the oxidation of arsenopyrite. In the9K medium with bacteria, the corrosion potential, the anodic slope, the cathodic slope and the polarization resistance decreased, and the corrosion current density increased with the temperature rising, this result indicated the arsenopyrite was more easily dissolution by oxidation corrosion. The electrochemical kinetic parameters changed slightly between the pH1.5and2.0, which was beneficial to the bacterial growth and the steady oxidation of arsenopyrite. The formation of ferric arsenate, iron hydroxide and elemental sulfur could be reduced by controlling the pH of slurry and the oxidation effect of arsenopyrite could be improved. The electrochemical kinetic and leaching kinetic researches indicated the indirect oxidation mechanism in the biooxidaiton of arsenopyrite was predominant, the leaching kinetic process of arsenic-bearing gold concentrates was controlled by the solid product layer diffusion.The technical parameters of biooxidation and cyanidation of the high arsenic carbon-bearing gold concentrate were optimized by the conditional experiments. After9days' biooxidation,95.77%arsenic,95.25%iron and86.64%sulfur were removed, the sample weight loss rate was26.48%. After36hours' cyanidation, the extraction rates of gold and silver reached95.68%and75.64%respectively, which were78.14%and24.71%higher than that of72hour's conventional cyanidation of untreated gold concentration. Therefore, the biooxidation not only remarkably enhance the cyanide leaching of gold, but also reduced the cyanide leaching time.In the industrialization practice of cyanidation of high copper carbon-bearing gold concentrates with addition of enriched oxygen and PbO, the gold extraction rate increased from88.56%for conventional cyanidation to9753%, the sodium cyanide consumption decreased from19.86kg/t for conventional cyanidation to11.68kg/t. On the premise of improving technical economical indexes, the actual capacity increased from53.19t/d for conventional cyanidation to72.8t/d, these results indicated the technology could effectively improve the gold extraction, lower the sodium cyanide consumption, reduce the leaching time and extend the productivity.The industrialization practice of comprehensive recovery of cyanidation tailing by flotation indicated the flotation of copper, lead and zinc from cyanidation tailing was feasible. Qualified concentrates could be produced under proper operating condition, however the discrepancies of degree of inhibition by cyanide of different components and the composition of cyanidation must be took into account when choosing the flotation technology, in principle, the selective flotation of lead technology was adopted. The problem of excessive impurities must be considered and controlled, otherwise the efficiency of enterprises would be impacted remarkably by the decreasing of products quality for the excessive impurities.The industrialization practice of biooxidation of arsenic-bearing gold concentrates showed that the TCJ culture was suitable to pretreat the refractory gold concentrate containing8%arsenic. For the refractory gold concentrate containing21.89%arsenic, after blending with low arsenic carbonate gold concentrate, the mole ratio of iron and arsenic was controlled between4.6%and5.2%, the biooxidation and the cyanidation of the high arsenic concentrate were remarkably improved:the removal rate of iron and arsenic by biooxidaton were enhanced from6.14%and7.38%to89.90%and93.60%respectively, the gold and silver extraction were increased from64.18%and35.93%to97.78%and88.83%respectively.The researches in this dissertation provide theoretical and technical guidance for the direct cyanidation of high copper carbon-beatring gold concentrates and biooxidation-cyanidation of arsenic-bearing refractory gold concentrates.
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