| In this paper,a certain refractory gold ore was researched,the bacterial oxidation pretreatment experiment was carried out.Gold concentrate and bacteria oxidation slag were analyzed through process mineralogy.Methods of cyanida and non-cyanide of are generally used for bacteria oxidation slag.This thesis researched bacterial oxidation slag with non-cyanide gold leaching method.Methods:thiourea,iodide and thiosulfate method.Process mineralogy analysis showed that:after bacterial oxidation pretreatment on gold concentrate,bacterial oxidation slag particle size was less than 38?m,meettting the requirements of the subsequent experiment on granularity;Pyrite and arsenopyrite-the main carrier of gold in gold concentrate-were oxidized effectively;Au was enriched from 28.9 g·L-1 to 55.6 g·L-1,Ag was enriched from 20.1 g·L-1 to 38.0 g-L-1,As were reduced from 1.77%to 0.13%,Fe was reduced from 33.89%to 6.97%,S was reduce from 35.3%to 19.8%.Cyanide leaching gold experiment showed that:effect of direct cyanide gold leaching on the gold concentrate is not ideal,the gold leaching rate only reached 68.17%.after bacterial oxidation pretreatment on gold concentrate,of the bacteria oxidation slag cyanide gold leaching experimentwas carried out,in which the pulp density is 25%,through one-step gold leaching,the gold leaching rate?Leaching time 48h?reached 95.20%,and increased the direct cyanide gold leaching by 27.03%.Thiourea leaching gold experiment showed that the optimum leaching condition:pulp density was 20%,thiourea concentration was 10 g·L-1,the voltage was 240 mV,pH was 1.0,leaching temperature was 40?,leaching time was 5 h.Under the optimum leaching conditions,the gold leaching rate of gold concentrate was 58.47%,after bacterial oxidation pretreatment on gold concentrate,through one-step gold leaching,the bacterial oxidation slag of gold leaching rate was 81.78%,gold recovery rate increased by 23.31%.Iodide leaching gold experiment showed that the optimum leaching condition:room temperature,pulp density was 25%,iodine concentration was 1.0%,the molar ratio of iodine and iodine ion was 1:6,hydrogen peroxide concentration was 3%,pH was 5.0,leaching time was 4 h.Under the optimum leaching conditions,the gold leaching rate of gold concentrate was 55.57%,after bacterial oxidation pretreatment on gold concentrate,through one-step gold leaching,the bacterial oxidation slag of gold leaching rate was 80.32%,gold recovery rate increased by 24.75%.Thiosulfate leaching gold experiment showed that the optimum leaching conditions:room temperature,pulp concentration was 25%,sodium thiosulfate concentration was 0.3mol·L-1?concentration of sodium sulfite was 0.3 mol·L-1,copper sulfate concentration was 5 g·L-1,ammonium sulfate concentration was 50 g L-1,ammonia concentration was 1.0 mol L-1,pH was 9.5,leaching time was 20 h.Under the optimum leaching conditions,the gold leaching rate of gold concentrate was 67.52%,after bacterial oxidation pretreatment on gold concentrate,through one-step gold leaching,the bacterial oxidation slag of gold leaching rate was 92.39%,gold recovery rate increased by 24.87%.One-step gold leaching rate of different gold leaching methods:for thiourea method,gold leaching rate was 81.78%;for iodide method,gold leaching rate was 80.32%;for thiosulfate method,gold leaching rate was 92.39%.Gold leaching rate of cyanide gold leaching was 95.20%. |
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