I. Overview (1) Introduction to company development Hubei Sanxin Gold Copper Co., Ltd. (hereinafter referred to Sanxin company) was founded in 1999, formerly Jiguanzui gold. The Jiguanzui Gold Mine was founded in 1988. In 1992, it produced 250t/d production capacity; in 1994, it started construction of the second phase, and in 1997, it was put into operation, and the processing capacity was 800t/d. In 1999, the third phase of the project started construction, mainly to develop the Taohuazui copper-gold deposit, which was completed in 2002. Put into production. The total production scale of the current selection is 1800t/d. In 2003, it produced 1095kg of gold, 10245t of copper, an output value of 250 million yuan, and a profit of 40.76 million yuan, a net increase of 24.15 million yuan over the same period of the previous year. (2) Raw ore properties Copper and gold mining industry type metal skarn iron ore, copper ore including copper gold ore, copper ore, iron ore, copper-gold, copper, gold iron ore sulfur, a monosulfide ore. The metal minerals of ore are mainly magnetite, limonite, pyrite, chalcopyrite and the like. Gangue minerals are quartz, chlorite, sericite, orthoclase, albite, apatite and the like. Quartz has an irregular granular crystal structure. Limonite, magnetite, chalcopyrite, pyrite, etc. are filled in the gangue mineral grains and in the fissures. The results of multi-element analysis of ore are shown in Table 1. Table 1 Ore multi-element analysis results table The gold minerals are mainly natural gold, a small amount of silver and gold ore, the former accounts for 70%, the latter accounts for 30%; the gold has a fine particle size, mainly between 0.07 and 0.02 mm, mainly occurring in the fissures of pyrite and gangue. in. (3) Beneficiation process The ore dressing plant separates the ore of the Jiguanzui and Taohuazui mining areas in two series, and the production capacity of the two sets of grinding and floating series is 800t/d and 1000t/d respectively. The beneficiation process is: Cu, Au, S mixed flotation - separation of Cu, Au and S after mixing and re-grinding - weak magnetic separation. The recovery rates of gold and copper were 83% and 92% respectively, the iron recovery rate was 20.64%, and the tailings yield was as high as 87.92%. (4) Tailings properties The yield of tailings produced by the flotation process is 87.92%, calculated according to the annual processing capacity of 600,000 tons, with an annual output of about 52.18 million tons of tailings; tailings fineness - 200 mesh content of 65%. The elements with recyclability in tailings are gold, copper and iron. Grade: Au 0.41g/t; Cu 0.15%; Fe 25.10%; MFe 6.50%. 2. Experimental study on recovery of valuable elements from tailings The test conducted a medium-strong magnetic field iron test and a re-election test. Weak magnetic field selection of iron has been directly installed equipment for industrial production before this test. (1) Medium and strong magnetic field recovery iron test The iron grade of the ore sample taken in the test was 21.24%. 1. Magnetic field recovery of different magnetic field strengths The test results are shown in Table 2. Table 2 Results of iron selection test with different magnetic field strength From the results in Table 2, it can be seen that as the magnetic field strength increases, the concentrate yield and recovery rate also increase, but the iron grade decreases, although the iron grade in the ore is 21.24%, but the concentrate iron grade is only 50%. about. This indicates that there are not many ferromagnetic iron minerals in the tailings, which are basically continuous or weak magnetic iron minerals. If you want to obtain 60% or more iron grade concentrates by one sorting, Difficulty, for this reason, the primary concentrate of a magnetic separation was reground and re-selected directly. The concentrate obtained by magnetic field magnetization of 381972A/m was ground to a content of -200 mesh, which accounted for about 85%, and two different magnetic field strengths were selected. The test results are shown in Figure 1. Fig.1 Selected quality process of iron coarse concentrate after regrind 2. Direct magnetic separation selection test of coarse concentrate The iron concentrate obtained by magnetic field selection of 381972A/m field is not treated at all, and directly enters the secondary multipole (more than 20 poles) low field strength magnetic separator. The test results are shown in Figure 2. Figure 2 Iron coarse concentrate directly selected quality process It can be seen from the test results of Fig. 1 and Fig. 2 that the crude concentrate obtained by rough selection of 381972 A/m field strength, regardless of regrind or not grinding, may obtain concentrate of about 60% iron grade by secondary selection; The re-grinding process selection index is slightly better than the non-grinding process, but the non-grinding process is relatively simple, and there is no need to increase the grinding equipment . Therefore, after the flotation tailings are selected by the 381972A/m field strength magnetic separator, the coarse concentrate is selected. No longer grinding, directly using multi-pole (20 poles or more) low field strength magnetic separator for selection. (2) Re-election of gold recovery test The occurrence of gold in the tailings is the congruent body symbiotic with the gangue, and the grain size is coarse. The gold in the tailings is first enriched by a chute, and the obtained concentrate is selected by a shaker to finally obtain a qualified product. The test sample was taken from the tailings slurry produced on site, and in the case of continuous production, it flows to the test chute. A total of different graffiti paving materials, different chute slopes, and chute concentrates were selected for testing experiments. The test results show that the slope of the chute is 3.0%, and the gold recovery effect is the best when the sack is used for paving. The gold grade of the chute concentrate can reach 3-6g/t. After the selection of the ordinary 6-S shaker, the final concentrate grade can be Up to 30g / t, the yield reached 0.096%, the Au recovery rate reached 5.61%. Third, industrial production practices (1) Determining the process According to the small test results and comprehensive consideration of other factors (such as on-site site, investment, production costs, etc.), after sufficient demonstration, the process of comprehensive recovery of gold and iron from tailings as shown in Figure 3 was determined. Figure 3 tailings recovery valuable element process (2) Equipment selection and production The main equipment used is shown in Table 3. Table 3 Equipment for the selection of valuable elements for tailings recovery (3) Tailings comprehensive recycling workshop After careful preliminary testing and demonstration, the test results show that the tailings can be comprehensively recovered with various valuable elements, and in October 2002, Sanxin's tailings comprehensive recycling workshop was built, with 30 employees and 4 classes and 3 operations. 8h working system. (4) Production practice The tailings recovery workshop is located at the foot of Jiguanzuishan where the beneficiation workshop is located. Because the height difference is not enough, the medium-strong magnetic rough-concentrated concentrate is transported by the sand pump to the multi-pole magnetic separator, and the rest of the operation is self-flowing. The process uses the process determined by the experiment (see Figure 3). After more than one month of production and commissioning, the production of tailings recovery workshops tends to be normal, and various indicators have also stabilized. The production targets for 2003 have met the design requirements. The statistical indicators are shown in Table 4. In addition, the gold concentrate in the re-selected product also contains various elements such as 2% copper, 35% sulfur, and 35g/t silver, which can be priced at the time of sale. Table 4 Valuable element indicators for tailings recovery and production in 2003 Fourth, the economic benefit calculation According to this calculation, the tailings recovery workshop can recover 8928g of gold, 3172t of copper, 6510g of silver, 12480t of iron concentrate and 65.1t of sulfur. According to the average market price in 2003: gold 80 yuan / g, copper 27,000 yuan / t, silver 0.8 yuan / g, sulfur 150 yuan / t, iron concentrate 400 yuan / t, these products can create a total output value of 5.82 million yuan. V. Conclusion At present, there is 18.41% iron in the tailings after magnetic separation, which is mainly iron ore. In view of the current good market conditions in the iron market, we are now studying how to further develop and utilize this part of the iron; there is a possibility that the yield and recovery rate of the chute selection will be further improved. The successful application of this process has increased the recovery rate of Sanxin's ore dressing by 0.66 percentage points. The magnetic iron in the mineral resources has been fully recovered, and the economic benefits obtained are very considerable. At the same time, the load on the tailings pond is reduced and solved. The employment problem of more than 30 workers has achieved certain social benefits; the investment in the process is small (about 1 million yuan), the conventional equipment, the process is simple, the production cost is low, and it is easy to implement. Good Filter Mesh,Polyamide Polyester Screen Mesh,Custom Filter,Carbon Filter shaoxing gesheng wire mesh co., ltd , https://www.gscreenmesh.com