From the production efficiency of the mine, the gold mine gold recovery directly affects technical and economic benefits of the mine, so each mine attach great importance to improve the recovery rate of gold production problems in [1-2]. Tibet to get gold for the day as a series of studies conducted by test conditions, determine a reasonable process and reagent system provides a theoretical basis for future beneficiation plant production process design. After experimental research, the gold recovery rate was increased to over 93% on the premise that the gold concentrate grade was greater than 170g/t. First, the nature of the ore The Nongru gold deposit in Tibet is located in the eastern section of the Gangdese metallogenic belt in Tibet. It is one of the typical gold deposits in the metallogenic belt and belongs to the altered rock deposit. Studies have shown that the main mineral composition of the ore in addition to natural gold, silver, endures pyrite, arsenopyrite as well as lower levels of minerals, stibnite, etc., the main gangue of quartz, feldspar and clay. Gold mainly exists in the form of independent gold minerals and similar materials. The independent gold minerals are natural gold, which are finely divided and irregularly granulated between clay mineral particles or between clay minerals and quartz grains. The EPMA results show that the gold color is very high, ranging from 99.2% to 99.6%. The particle size range of gold ranges from less than 0.001 mm to 0.34 mm, which is mainly in the range of >0.02 mm, accounting for 52.13%. The main gold-bearing mineral pyrite and arsenotic sand have a wide particle size range, ranging from <0.01mm to >3mm, mainly concentrated in the fine particle range, but the specific content of gold in pyrite and arsenopyrite is still unclear. . Pyrite and arsenopyrite account for 1.18% of the ore. Clay minerals are the main gold-bearing minerals of independent gold minerals (natural gold), and their particle sizes are mainly concentrated at <0.05mm. The clay minerals in this type of ore account for 50.29%. The grain size of natural gold is shown in Table 1. Table 1 Embedding granularity of natural gold The main gold-bearing mineral of the ore is pyrite and arsenopyrite, and its particle size distribution characteristic curve is shown in Figure 1. Fig.1 The horn rock type ore in the Nongru gold deposit, Tibet Grain size characteristics of pyrite and arsenopyrite â—-The proportion of each material grade; â– -Grain level cumulative content Second, the test method According to some studies on the flotation reagent system of gold sulfide ore, water glass is selected as a dispersant in this test, copper sulfate as activator, ADDP + xanthate as collector agent composition, as the oil # 2 Foaming agent. Then, the single-factor and multi-level test methods are used to optimize the water glass, copper sulfate and butylamine black medicine + yellow medicinal amount and grinding fineness. Since the amount of foaming agent has little effect on the test, the amount is combined with relevant data to obtain a suitable one. Value. Based on this, an open circuit test and a closed circuit test were carried out. The closed circuit test is a rough selection, four sweeps, and a second selection test procedure. The agents used in the flotation test were all industrially pure. Third, the study of test conditions On the basis of the exploration test, the amount of crude drug selected for water glass, copper sulfate, butyl sulphate and butylamine black drug was tested. The test procedure and the pharmaceutical system are shown in Figure 2. Figure 2 rough selection test (1) Water glass dosage Water glass is used as a dispersing agent in the test to disperse the fine mud in the slurry. The water glass is added in the grinding system. Under the condition of changing the amount of water glass, the dosage of other chemicals is determined according to relevant data. A rough selection and a selective flotation test were carried out, and the test results are shown in Fig. 3. Figure 3 Relationship between water glass usage and gold grade and recovery â—‹-Au grade; â–²-Au recovery rate It can be seen from Fig. 3 that with the increase of the amount of water glass, the fine mud in the slurry is highly dispersed, and the excess water glass can inhibit the gangue to a certain extent. For this reason, when the amount of water glass is increased, the grade of concentrate is gradually increased. When the amount of water glass is more than 1000g/t, the recovery rate of gold does not change much, and even has a tendency to decrease. Therefore, considering the comprehensive consideration, the amount of water glass is taken as 1kg/t. (B) butylamine black medicine and Ding Huang pharmaceutical dosage According to the test procedure of Figure 2, the combination of butylamine black and diced yellow syrup as a collector, the amount of water glass is 1kg/t, and the effect of the dosage of butylamine black and butyl yellow on the flotation index is tested. The test results are shown in Figure 4. Figure 4 Relationship between the dosage of butylamine black drug + Dinghuang and gold grade and recovery â—‹-Au grade; â–²-Au recovery rate It can be seen from Fig. 4 that with the increase of the dosage of butylamine black medicine and Dinghuang, the grade and recovery rate of the concentrate gradually increase, but when the butylamine black medicine + Dinghuang medicinal is greater than (10+60) g/t At that time, the recovery rate of flotation gold concentrate began to decrease; when the dosage of butylamine black medicine + Dinghuang was (10+60) g/t, the gold concentrate grade and recovery rate were better, therefore, the collector butylamine The amount of black medicine and diced yellow medicine is taken as (10+60) g/t. (three) the amount of copper sulfate After determining the amount of dispersant and collector, a flotation test of the amount of copper sulfate was carried out, and the test procedure was the same as above. In this test, the main role of copper sulfate is to activate gold-containing pyrite and arsenopyrite, thereby promoting the interaction between the collector and the mineral, and improving the floatability of the gold-containing mineral. When the amount of water glass is 1 kg/t, and the amount of butylamine black medicine + Ding yellow is (10+60) g/t, the amount of copper sulfate is tested. The test results are shown in Fig. 5. Figure 5 Relationship between the amount of copper sulfate and gold grade and recovery â—‹-Au grade; â–²-Au recovery rate It can be seen from Fig. 5 that when the amount of copper sulfate is 400 g/t, the grade and recovery of gold are better. (4) Grinding fineness flotation The effect of grinding fineness (particle size) on the flotation system should not be neglected. If the particles are too large, it will not easily float out with the bubbles, resulting in a low gold recovery rate. If the particles are too fine, the phenomenon of over-grinding will occur, and it will be difficult to select the drug. Out. To this end, based on the test conditions determined above, a flotation test of grinding fineness was carried out, and the test results are shown in FIG. 6. Figure 6 Relationship between grinding fineness and gold grade and recovery rate â—‹-Au grade; â–²-Au recovery rate It can be seen from Fig. 6 that when the grinding fineness -0.074mm accounts for 91.97%, the gold concentrate grade and recovery rate are the best. When both rough grinding and overgrinding result in a corresponding decrease in grade and recovery rate, it is in line with the theory. Therefore, the choice of grinding fineness -0.074mm accounted for 91.97%. Fourth, open circuit test Based on the rough selection test conditions determined above, and according to the actual test conditions, the amount of each drug selected is gradually decreased, and the open-circuit flotation test of FIG. 7 is performed. The test uses a rough selection, four sweeps, and a second selection of open circuit. The fineness of rough grinding is -0.074mm, accounting for 91.97%. The dosage of each agent is shown in Figure 7. The test results are shown in Table 2. Figure 7 Open circuit test procedure and pharmaceutical system Table 2 Open circuit test results It can be seen from Table 2 that due to the synergistic effect of various chemicals, the open-circuit process test obtained a flotation index with a gold concentrate grade of 200 g/t or more and a gold recovery rate of 85% or more. In order to examine the impact of the return of the mine on the flotation index, the production site was simulated and a closed circuit test was carried out on the basis of the open circuit test. V. Closed circuit test The closed circuit test flow is shown in Figure 8. On the basis of the open circuit test, the closed-circuit process test returns to the principle of the previous operation according to the order of the middle mine. The chemical system of the first unit is shown in the open circuit test, and the rear unit is seen to reduce the amount of the chemical in the test. According to the test in Figure 8. The process performs multiple flotations until the flotation system reaches equilibrium. Finally, the recovery rate of gold concentrate was 93.79%, and the concentrate grade was good indicator of 172.83g/t. The test results are shown in Table 3. Figure 8 Closed-circuit test procedure and pharmaceutical system Table 3 Closed circuit test results Conclusion 1. Process mineralogical studies show that the main carriers of gold are pyrite and arsenopyrite, which are mainly distributed in fine-grained grades; natural gold is mainly distributed in clay minerals of <0.05mm fine-grained grade. 2. The mineral has a fine particle size and is easy to handle by flotation. 3. The beneficiation test process is a rough selection, four sweeps, and a second selected flotation process. The closed-circuit test results show that the gold concentrate grade is greater than 170g/t, the gold concentrate yield is 3.00%, and the gold recovery rate is greater than 93.00%. . references [1] Zhou Yuan. Experimental study on the recovery of gold, silver, copper and sulfur from a gold ore flotation-thiourea carbon leaching [J]. Gold, 2002, 23 (2): 41243. [2] Cui Dewen, Sun Jigui, Lei Shibin. On the support conditions for guaranteeing the sustainable supply of gold mines [J]. Gold, 2002, 24 (1): 124. [3] Duan Fengmei 1 Research and application of mixed agent system to improve the recovery rate of mineral processing[J]. 金属矿,2007(11):69270. Author unit Beijing University of Science and Technology (Liu Xu, Wang Huajun, Wang Yanbing, Li Lamei, Xie Yuling) Tibet Kunlun Mining Development Co., Ltd. (Wang Aiguo) Mitered Fittings,Marine Pe100 Plastic Pipe,Marine Pe100 Plastic Pipe For Accommodation,Marine Pe100 Plastic Pipe For Water Supply Jingjiang Haihong Plastic & Rubeer Science -Technology Co.,Ltd , https://www.marineplasticpipe.com