In the current cyanide gold extraction, accelerating the generalized leaching of gold and reducing the consumption of sodium cyanide are two major factors affecting the technical and economic effects of the cyanide process. At present, an effective way to reduce the consumption route and increase the cyanidation index is to replace the air leaching with an oxygen-rich method, which has been successfully applied in some mines. Brown iron oxide gold as a gold-bearing oxide ore mine, the main metallic minerals limonite, marcasite etc. times as high elevation since the mine is located at high altitude, low oxygen content in the air, using a conventional cyanidation process, After the need, the gold leaching can be stabilized and the leaching period is longer, which will directly affect the economic benefits of the mine. In order to ensure the gold recovery rate and shorten the gold leaching period, this paper proposes a new process of oxygen-rich leaching of gold oxide ore. The leaching time is only needed. Tests show that using this process can significantly increase the immersion rate and reduce the amount of sodium cyanide, and the recovery rate of gold can reach 96.68%. If activated carbon is added during the leaching process, the adsorption rate of gold can reach 99.14%, and a good test index is obtained. First, the nature of the ore (1) Ore composition The limonite ore vein quartz rock fragmentation and white vein quartzite, gold to gold fine particles encapsulated in a dense natural limonite and marcasite, excipients or exist between the limonite grains. Metallic minerals natural gold, silver, limonite, jarosite, gangue minerals are mainly quartz main carrier, white mica, sericite, potassium feldspar, limonite is gold. The results of multi-element analysis of raw ore are shown in Table 1. Table 1 Multi-element analysis results of ore /% (2) The state of occurrence of gold No gold was found in the original ore samples and the artificial sand samples. Natural gold was only found in the concentrate of the -0.9mm class ore selected by the shaker. There are three forms of existence: 1. Monomer gold may be dissociated from limonite, with a maximum particle size of 0.04 mm and a minimum of 0.001 mm. 2. The wrapped gold is in the limonite, the gold thickness is 0.03~0.002mm, and the structure of all the limonite wrapped with natural gold is dense. 3. Fine-grained gold is present in the iron ore in an ultramicroscopic state. Second, the laboratory test (1) Oxygen-enriched leaching mechanism Gold is dissolved in the presence of oxygen in the sodium cyanide solution According to the diffusion theory, it can be deduced that when [CN - ] / [O 2 ] = 6, the gold dissolution rate reaches the limit, that is, when the free cyanide in the leaching solution and the molecular oxygen dissolved in the water, that is, the dissolved oxygen concentration reaches 6, Gold leaching speed is the best [2] . 1. Conventional cyanide leaching The test/16kg was ground to -74μm 65%, and charged into a 40L stirring leaching tank to make the slurry concentration reach 33%. Under the condition of pH 11 and cyanide concentration 0.3g/L, the air was filled with 1.6m. The leaching is carried out in 3 / h rows, and about 150 ml of pulp is taken out every 1 to 2 hours, and after filtration and washing, an analysis sample of the noble liquid and the leaching residue is obtained. At the same time, the dissolved oxygen content in the slurry was also measured, and the CN - /O 2 molar ratio was calculated. The CN - content in the precious liquid was measured and supplemented according to its consumption, so that the cyanide concentration was maintained at an appropriate level, and the total cyanide consumption was calculated to be 2.03 kg/t. The gold content of the leaching residue was analyzed, and the gold leaching rate at each time was calculated based on the result. The test results are shown in Figures 1 and 2. 1 showing a conventional pulp diffuse CN - / O 2 Figure 2 Relationship between regular diffuse time and leaching rate It can be seen from Fig. 1 and Fig. 2 that: (1) Since the air is filled in the conventional leaching, the oxygen content in the slurry is low, and the CN - /O 2 value fluctuates greatly and is much higher than the theoretical optimum. value. (2) The leaching rate of gold in the first few hours is slow, and the leaching fluctuates greatly in the later period, and the leaching rate is stabilized after 16 hours of leaching. 2. Oxygen-enriched leaching test For the oxidized ore, the conventional leaching time is long and the consumption of sodium cyanide is large. We have conducted an oxygen-rich leaching test to compare. The test conditions are almost the same as those used for conventional leaching, except that the filled air is replaced by oxygen, and the aeration amount is 0.07 to 0.1 m 3 /h. The test process is the same as the conventional leaching, and about 150 ml of pulp is extracted every 1 to 2 hours. After filtering and washing, the analysis of the precious liquid and the leaching residue is obtained. At the same time, the dissolved oxygen content in the slurry was also measured, and the N - /O 2 molar ratio was calculated. The N - /O 2 content in the precious liquid was measured, and the supplement was timely added according to the consumption thereof, so that the cyanide liquid concentration was maintained at an appropriate level, and the total cyanide consumption was calculated to be 1.04 kg/t. The gold content of the leaching residue was analyzed, and the gold leaching rate at each time was calculated based on the result. The test results are shown in Figures 3 and /4. Figure 3 N - /O 2 in the oxygen-rich leaching slurry Figure 4 Relationship between oxygen enrichment leaching time and leaching rate It can be seen from Fig. 3 and Fig. 4 that: (1) After charging for 8 h of oxygen enrichment, the value of N - /O 2 in the slurry is close to the theoretical optimum leaching rate ratio of 6, which creates conditions for accelerating gold leaching. . (2) During the oxygen-rich leaching process, the leaching rate of gold is stabilized at about 95% after 8 hours of leaching. Compared with conventional leaching and oxygen-enriched leaching, oxygen-rich leaching has many advantages over conventional leaching, not only in the leaching process, the leaching rate of the former is much faster than the latter, and in the consumption of sodium cyanide, oxygen-rich leaching The consumption is only 1.04kg/, the conventional leaching is 2.03kg/t, and the consumption is only 50% of the latter. Therefore, for such oxidation-containing gold ore treatment in the plateau region, oxygen-rich leaching obviously has great advantages. (3) The impact of grinding fineness on the richness of the rich Grinding fineness cyanidation test conditions: pulp concentration 33%, pH 1.05 ~ 11, cyanide concentration, 0.4g / L, cyanide time 42h, sodium cyanide dosage 1 ~ 1.5kg / t, alkalinity Calcium oxide, the dosage is 2kg / t, the test indicators are shown in Table 2. Table 2 Grinding fineness test indicators It can be seen from Table 2 that as the fineness of the grinding increases, the grade of the leaching slag decreases, and the leaching rate of gold increases. However, after the -74 μm particle size reached 65%, the change was not significant. Therefore, the fineness of the grinding is preferably -74 μm to 65%. (III) Effect of cyanide solution concentration on oxygen enrichment leaching Test conditions: pulp concentration 33%, pH value 10.5 ~ 11.0, grinding fineness -74μm accounted for 65%, cyanide time 42h, sodium cyanide dosage 0.7 ~ 1.3kg / t, calcium oxide for alkali adjustment, the amount is 2kg / t, the test results are shown in Figure 5. Figure 5 Cyanide solution concentration test results It can be seen from Fig. 5 that as the concentration of cyanide solution increases, the gold leaching rate increases, but after the cyanide solution concentration reaches 0.3 g/L, the increase rate is already small, so it is suitable to select a concentration of 0.3 g/L. (4) Charcoal immersion test The 1kg ore sample was leached according to the optimal cyanidation conditions preferred above, and 20 g of activated carbon was added to the slurry at the same time. After cyanidation and adsorption for 24 hours, the activated carbon was sieved out, and the gold-loaded charcoal, the leaching residue and the poor liquid product were obtained by filtration and washing. The test results are shown in Table 3. Table 3 Charcoal immersion test results Third, the conclusion The oxidized gold ore is a limonite splitting vein quartzite and a white vein quartz type gold deposit. The gold mineral is natural gold and has a fine particle size, and is mainly distributed between the limonite grains. According to the characteristics of this ore and its geographical location, it is proposed to use the "oxygen cyanide leaching process" to treat the leaching material with a fineness of -74μm, 65%, pulp concentration of 33%, and cyanide concentration. 0.3g/L, lime dosage is 2kg/t, pulp pH is 10.5～11.0, leaching for 24h, and activated carbon is added. Under this condition, the leaching rate of gold is 96.68%, and the adsorption rate of gold is 99.14%. Compared with the oxygen enrichment leaching and conventional leaching of the ore, the leaching rate of gold can be stabilized after 8 hours, while the conventional leaching is required. Therefore, the oxygen-rich immersion time can be shortened by about twice, and the atmosphere during the test. The amount of sodium used requires only half of the conventional leaching. references [1] Zhong Ping, Hu Yuehua, Oxygen-rich leaching mechanism and its application in cyanide gold extraction [Journal of Weinan Normal University, 1996 (6): 50-55. [2] Lu Xianjun, Introduction to Cyanide Gold Extraction [M]. Xi'an: Shaanxi Science and Technology Press, 2000, 134-135. Author unit Jiangxi University of Science and Technology (Hu Min, Cheng Wei, Luo Xianping) Fujian Zijin Mining and Metallurgy Design and Research Institute (Hu Min) Epoxy Accelerator,Epoxy Curing Accelerator,Epoxy Diluent For Coating,Epoxy Resin Promoter Luckypower Tech , https://www.czluckypowertech.com