The Research On Extracting Gold Process Of The Micro-disseminated Primary Gold Ore

The thesis focuses on research of the micro-disseminated gold ore. The analysis results of ore chemical composition that grade was 3.51 g/t, content of SiO2 was as high as 71.88 %.in addition, the content of organic of carbon even reached up to 2.51 %. the ore main minerals were primary composed with quartz, calcite and sulfide ore, while sulfide ore was given priority to with pyrite, A part of the gold existed clearance of different mineral. The package of quartz even reached up to 66.92 %, the sulfide is 15.94 % and the silicate is 1.44 %. The analysis results of SEM that surface of Quartz and pyrite are smooth,the structure are compact.According to the characters of the gold ore, in order to check leaching agent used muffle furnace or microwave roasting pretreatment. The results showed that non-cyanide extraction process after microwave roasting is best, microwave roasting temperature at 500 ℃,and baking time of 40 min, the dosage of non-cyanide agent TY-3 was 14 kg/t,Sodium hydroxide dosage was 8 kg/t, leaching time was 10 h, the gold leaching rate of 94.8 % was achieved. Therefore, making sure the agent TY-3 is the better leaching agent of the micro-disseminated gold ore.Experiment adopted wet chemical pretreatment process avoiding high energy consumption and serious environmental pollution of roasting produces. Research on the leaching gold process which non-cyanide leaching after alkali pretreatment, was non-cyanide leaching after two-stage pretreatment in add air or not. From the feasibility and cost considerations, to make sure the process of non-cyanide leaching after two-stage pretreatment is best. The results showed under the condition that the dosage of TY-1 was 4 kg/t, the dosage of TY-2 was 2 kg/t, Oxidation pretreatment time was 2 h.Sodium hydroxide was 20 kg/t, alkali leaching time was 4 h, add air during pretreatment, the dosage of calcium was 40 kg/t, the dosage of TY-3 was 8 kg/t, leaching time was 4 h, the gold leaching rate of 87.21 % can be achieved. Based on the process, the leaching residue was tested. Through the phase of the gold, the analysis of the sulfur and organic carbon,SEM and X-ray energy spectrum analysis.it was found that the process can effective recovery the gold from quartz and Silicate, the leaching rate can reach up to 97.17%.Sulfur and organic carbon removal rate were 39.69% and 37.05% respectively. The surface quartz and pyrite were corroded, the quartz was worse, that was why can get gold from quartz.The pretreatment agent cost of the process was 92.5 yuan/t. compared the process of pretreatment with the traditional hot pressing process, the process can reduce the cost of pretreatment,because it can be done in room temperature and atmospheric press. Compared with the roasting oxidation pretreatment process, it has advantages of low energy consumption and no pollution. compared with the biological oxidation process, it has short reaction period.