Study On The Improvement Of Gold Recovery From Low Grade Gold Ores Of Tuokuzibayi

According to the systimatic studies on the ore properties of low grade gold ores of Tuokuzibayi, the dissemination size of minerals is very fine, but the harmful impurities are less in ores, so the ore should be taken as the low carbon and arsenic, fine disseminated and hard-to-beneficiate gold ore. From the point of gold recovery, flotation is shuitable technology for the gold recovery from this kind of gold ore. Single flotation, tailings cyanidation and full slime cyanidation were studied in this dissertation, and the optimal process is composed of flotation and tailings cyanidation. Industrial test was also finished based on laboratory test results, and the optimum process conditions were finally confirmed, the gold recovery was improved from87%to94.61%.Laboratory tests of grinding fineness and reagent regime were also carried out. Good flotation index was obtained by using mixed collector instead of single collector. A remarkable effect was also produced by the use of mixed collector under different proportion of single collector instead of the simple mixing of single collector. The optimum conditions for flotation are determined as:92%-0.074mm,1800g/t Na2CO3,70g/t CuSO4,100g/t mixed collector,45g/t2#oil, and a good flotation index with gold grade53.28g/t and gold recovery90.05%in concentrate was also generated. Flotation tailings were then cyanided under the conditions of10kg/t lime,50g/t loosing agent,340g/t NaCN,30days leaching time, and the gold leaching rate is52.73%which is equal to the recovery of5.59%calculated from feed ore. The optimum technical conditions of full slime cyanidation are93.96%-0.074mm,2:1liquid-solid ratio,24h leaching time,8kg/t CaO,0.8kg/t NaCN,16g/L activated carbon, and the leaching rate is82.55%. The total gold recovery of the technology of flotation plus tailings cyanidation is1.87%higher than the technology of full slime cyanidation, and the cost of the former is30yuan/ton lower than the latter, so the optimal flowssheet is flotation plus tailings cyanidation.The pilot and industrial tests were also carried out based on the conditions of laboratory test. The finally conditions for industrial test were determined as follows:91.22%-0.074mm,1800g/t Na2CO3,60g/t CuSO4,95g/t mixed collector,40g/t2#oil,10kg/t lime,340g/t NaCN,40g/t loosing agent, pH=10.5, and a flotation concentrate with gold grade of52.73g/t and gold recovery of89.53%was finally produced. The gold leaching rate of flotation tailings is51.61%which is equal to the gold recovery of5.08%calculated from feed ore.The total gold recovery of94.61%was obtained by using new technology in industrial test.By the improving of technical process, the actual capacity was enlarged from450to465t/d, and the gold recovery was also improved from87%to94.61%. More than4500t ore can be trated per year, and the profit of5.4433million yuan per year is also obtained.