Practice of copper-zinc-sulfur polymetallic ore dressing production
In China, sorting copper sulfur zinc metal polymetallic ores is the main method of flotation. Due to the dense symbiosis of useful minerals such as copper, zinc and sulfur in the ore, the floating between the minerals overlaps, the higher the content of yellow iron accelerates the oxidation of the ore, etc. The separation of copper, zinc and sulfur is generally difficult. Copper beneficiation plant company are now 700t / d sulfur concentrator scale copper-zinc, copper preferably selected using some - mixing fine regrinding - sulfur separation process, Cu and Zn, Cu, Zn sulfur Ores process, after many years of production practice, the growing process Mature, production indicators are relatively stable.
First, the nature of the ore
The mines of Tongdu Company are filled with medium-temperature hydrothermal fissures to replace the copper-zinc-sulfur polymetallic sulfide deposits. The deposits are divided into two main types, namely, disseminated ore and massive ore.
The main metal ore minerals include pyrite, sphalerite, chalcopyrite, chalcocite small amount, tetrahedrite, galena, hematite, magnetite, limonite, quartz gangue minerals, barite, sericite, a small amount of calcite, chlorite, dolomite, feldspar. Chalcopyrite and sphalerite are filled in the fissures and granules of pyrite to form a packed-filled structure, which is closely connected to each other. The results of multi-element analysis of raw ore are shown in Table 1. The results of copper-zinc chemical phase analysis are shown in Table 2.
Table 1 Results of multi-element analysis of raw ore
Table 2 Results of copper and zinc chemical phase analysis
Second, process and production analysis
(1) Site process layout and features
Tongdu Company's concentrator adopts partial preferential copper-mixed regrind-copper-zinc-sulfur separation process. The principle flow chart is shown in Figure 1.
Figure 1 Process of mineral processing
Due to the uneven embedding of copper minerals, when the original ore is milled to -0.074mm, 72%, some copper minerals have been dissociated, and some copper minerals which have been separated by monomers are selected first. come out. The copper tailings are preferentially selected for mixed flotation. After the flotation, the tailings, which account for 70% of the ore production, are lost, thus maximizing the cost of processing. The mixed concentrate is sent to a ball mill for secondary grinding, and is pre-inspected and classified, and the graded overflow -0.048 mm accounts for 85%. At this time, the copper-zinc-sulfur mineral has been in a monomer dissociation state. First, the zinc and sulfur are inhibited for secondary copper selection, followed by zinc and sulfur separation. After the zinc concentrate is selected, the remaining tailings are sulfur concentrates. Among them, the secondary copper selection operation and the zinc selection operation all adopt rapid flotation. The main purpose is that after the ore is reground, the floatability between the same target minerals also has a large difference, so that the floatability is better. The ore particles first come up to reduce the burden of subsequent operations. After the secondary flotation operation, the recovery rate of the operation was increased by 10% and the recovery rate of the zinc-selecting operation was increased by 20%. At the same time, the zinc-sulfur separation operation uses steam heating, and the temperature increases the temperature of the zinc-selecting slurry by 8-10o. One of the purposes of steam heating is to accelerate the oxidation of pyrite and increase the difference in floatability between zinc and sulfur. Secondly, it increases the flotation rate and reduces the consumption of zinc-selecting chemicals.
(2) Target mineral collector
In the preferential copper selection, the collector is a mixture of methyl sulfamate and BK301, and the mixing ratio of methyl thiourethane to BK301 is 4:1. Methyl sulphate is sensitive to the capture of copper in the presence of zinc-sulfur inhibitors, has good selectivity, and has both foaming properties, and has a weak effect on zinc and sulfur. The role of BK301 is mainly to capture the associated gold in the ore. In the production practice of the company's plant selection, it was found that the single grade of methyl sulphate was used as the preferential copper-selecting agent. The grade and recovery rate of copper concentrate 1 were good, but the content of zinc in copper concentrate 1 was obvious. High, this is not conducive to the improvement of zinc recovery and the sale of copper concentrate powder; the single grade of BK301 copper concentrate 1 is high, but the recovery rate is low, mainly because the foaming of BK301 is not good enough. After many years of exploration, it was finally determined that the mixing ratio of methyl sulphate and BK301 was 4:1. The ratio of this mixed agent took into account the grade and recovery rate of copper concentrate 1 and the loss rate of zinc in copper concentrate 1.
In the mixed flotation section, the collector mainly uses a mixture of butyl xanthate and a small amount of methyl thiosulphate and BK301. The mixture of methyl thiourethane and BK301 is added to the first tank of the mixed flotation rough selection, and the butyl xanthate is added to the latter tanks of the mixed flotation and the sweeping portion. This reduces the effect of butyl xanthate on the separation of the mixture; at the same time, the floatability is better, but the copper mineral that does not come up in the preferential copper selection floats up in time. In the production practice, it is found that for the end tail with the same target mineral content, the larger the amount of mixed butyl yellow is, the more difficult the mixing and separation operation is. These problems indicate that butyl xanthate has a strong catching power and has a significant effect on copper-zinc-sulfur collection, but the selectivity is poor. Due to the addition of butyl xanthate to the mixed flotation, although re-grinding, there are many xanthate ions in the secondary copper-slurry slurry. Under normal circumstances, the secondary copper selection is not added to the collector, only a very small amount of methyl thiourethane and BK301 mixture is added. Zinc is selected as a collector for zinc.
(3) Zinc-sulfur mineral inhibitors
In order to effectively separate copper-zinc-sulfur minerals, a combination is used in production.
Inhibitors to inhibit zinc-sulfur minerals. Sodium sulfide, sodium sulfite, zinc sulfate, and lime are used to inhibit zinc minerals. The ratio of sodium sulfite to zinc sulfate is 1:1, and the zinc inhibition effect is better when added in this ratio. At the same time, the use of reasonable control of the pulp pH to inhibit zinc and sulfur. In the preferential copper selection, the pH value of the rough-selected pulp is controlled at about 10. The high pH not only increases the zinc content in the copper concentrate, but also increases the content of the target mineral in the tailings. The pH value of the secondary copper selection operation is controlled near 12, and the pH is too high, and the foam is sticky and easy to run; the pH is too low and the sulfur rises more, which affects the grade of copper concentrate 2. The pH of the zinc roughing operation is controlled at around 10.5. Lime mixing is used in production to inhibit pyrite.
(4) Zinc mineral activator
Copper sulphate is a commonly used activator of sphalerite. In the ore dressing industry test, it is found that the content of zinc minerals in the tail tail is difficult to drop. At the same time, due to the mixed selection of large doses of butyl xanthate, the mixing and separation operation environment deteriorates and the production index declines. Therefore, adding an appropriate amount of copper sulfate in the mixed-sweeping operation has a remarkable effect, and the zinc mineral in the final tail is greatly reduced. This practice is called asynchronous flotation. After the asynchronous flotation, the content of the target minerals in the tailings has been maintained at a low level in recent years. It should be noted that the sphalerite activated by copper sulphate should be difficult to suppress again, but after regrind, a large amount of fresh surface is produced during the mineral dissociation process, and such sphalerite can still be effectively suppressed.
(5) Other drugs and effects
In the production, sodium sulfide and activated carbon are used for drug removal treatment. Especially in the secondary copper selection operation, a large amount of sodium sulfide and activated carbon are required to remove the remaining xanthate in the mixed concentrate. At the same time, sodium sulfide also has the functions of cleaning the mineral surface, precipitating ions, and vulcanizing. Pine oil is used as a foaming agent in production, but it is limited to zinc-selective cleaning.
(6) Production indicators of Tongdu Company in recent years (see Table 3).
Table 3 Comparison of production indicators and design indicators
Third, the conclusion
For the complex polymetallic sulfide ore with disseminated and blocky unevenly embedded, the partial preferential copper-mixed regrind-copper-zinc-sulfur separation process is a suitable and mature process. The choice of a suitable collector and an effective combination inhibitor is the key to the separation of copper, zinc and sulfur. The implementation of steam heating has resulted in a significant increase in zinc recovery. The application of fast flotation has led to a steady increase in the recovery rate of copper and zinc. The application of the cyanide-free process has played a positive role in environmental protection and achieved sustainable development. The company's production practices have positive implications for other mines of the same type.
references
[1] Hu Xigeng. Non-ferrous metal sulfide ore dressing [M]. Metallurgical Industry Press.
[2] Nanchang Nonferrous Metallurgy Design and Research Institute. Pingshui Copper Mine 500 Plant Initial Design Specification [R].1984.
[3] Hunan Institute of Nonferrous Metals. Pingshui Copper Ore Dressing Industry Production Test Report [R]. 1987.
[4] Beijing Research Institute of Mining and Metallurgy. Improving the low-grade associated gold in Pingshui Copper Mine [R].1991.
[5] Pingshui Copper Mine Concentrator Laboratory. Pingshui Copper Mine Concentrator Process Check Report [R].2000-2004.
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