Study lead zinc ore beneficiation process a high-carbon, high-sulfur complex refractory
Guo Liangming Wang Gengchen Li Yuelin He Haitao
Abstract: A study on a high-carbon, high-sulfur lead-zinc ore in Inner Mongolia shows that the ore is a complex refractory lead-zinc ore. The minerals are inter- and non-uniformly intercalated between the minerals and the gangue. Dissociation; the carbonaceous and secondary slime in the ore seriously interfere with the flotation process, and the consumption of oil is large; the lead-zinc mineral is poorly floatable and the floating speed is slow; the pyrite in the ore is easy to float and difficult to suppress; Zinc minerals are dominated by iron sphalerite, which affects the improvement of zinc concentrate grade. Through the exploration and experiment of various process schemes, it was finally determined to adopt the flotation-based process, and the new flotation reagents A3 and M3 were trial-produced, and the test obtained a good selection index.
Key words: high sulfur; high carbon; complex refractory lead-zinc ore; new agent
CLC number: TD925.9 Â Â Â Â Â Â Â Document identification code: A
Entrusted by a company in Inner Mongolia, lead-zinc separation of lead-zinc ore from its subordinate mines yields a single lead-zinc concentrate and zinc concentrate. It is required to focus on the recovery of zinc minerals while producing qualified lead concentrates as much as possible.
1 ore nature
Metal ore was mainly pyrite, sphalerite iron, followed by pyrrhotite, galena. The gangue is mainly composed of quartz , silicate minerals and calcite , followed by graphite (carbonaceous). Among them, iron sphalerite is the most important zinc mineral in ore. It is irregular and his granular aggregate. The grain size is uneven, generally 0.02~2mm. It is a coarse and medium-fine non-uniform inlay; galena is mainly It is irregularly granular and has a fine particle size, generally less than 0.1mm, which is particularly closely related to the inclusion of iron sphalerite. Pyrite is the most sulfided metal sulfide mineral in the ore, mainly pyrite, followed by Pyrrhotite. The particle size is generally in the range of 0.1 to 2.0 mm, and is a medium coarse particle inlay. It is most closely related to the inclusion of iron sphalerite, followed by minerals such as galena and iron oxide; most of the carbonaceous materials are scaly and fine-grained in the sphalerite and galena. The results of multi-element analysis of raw ore are shown in Table 1.
Table 1 Multi-element analysis results of ore /%
element | Pb | Zn | S | Fe | Cu | Cd | C | CaO | Al 2 O 3 | SiO2 | MgO | Au | Ag |
content | 2.45 | 9.50 | 29.67 | 24.97 | 0.011 | 0.024 | 7.14 | 5.28 | 2.30 | 12.03 | 2.70 | <0.1 | 4.21 |
Au and Ag grade units are g/t, the same below.
2 flotation test
2.1 Flotation process plan selection
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For the lead-zinc-sulfur complex sulfide ore, only the recovery of lead and zinc is considered. At present, the process plan for the single-product production of lead-zinc ore flotation at home and abroad is: preferentially selecting lead, re-selecting zinc, lead-zinc and other floatable-re-separation, post-selection Three process schemes, such as zinc, lead and zinc, full-mix flotation and re-separation.
The study of ore properties shows that the content of carbonaceous and secondary slime in the ore is high, and some carbonaceous materials are extremely easy to float. For example, the two processes of floatation and lead-zinc full-mix flotation are used, which will be the whole flotation process. The interference is large, affecting the lead and zinc flotation indicators. Therefore, some easily floatable carbonaceous materials should be removed or preferentially selected with lead to ensure the quality of zinc concentrate. The iron ore in the ore is also high. The sulfur grade is 29.67%, which has a certain comprehensive recovery value. However, due to factors such as price and sales, the contract does not require the recovery of this part of pyrite. Preliminary tests have proved that most of the pyrites are highly floatable and extremely difficult to suppress. For example, lead-zinc and other floatable and lead-zinc full-mix flotation, some of the pyrites will reduce the floatability of lead and zinc minerals and prolong The flotation time, and the unsuppressed easy-to-float iron ore, adsorbs the collector after it floats, which brings more difficulties to subsequent separation. If the priority lead is selected and the zinc is re-selected, the above contradiction can be alleviated. In addition, the main metal minerals in the ore are coarse and medium-polar unevenly embedded. It is necessary to stage the grinding to remove the monomer. If a section of grinding is used, some lead-zinc minerals will be over-grinded, the floating speed will be reduced, and the flotation will be extended. time. In order to ensure the floatability of lead and zinc minerals and combine with the actual situation of the concentrator, it is decided to adopt a two-stage grinding method.
In summary, the principle flow for determining the flotation test is as follows: a two-stage grinding method, a lead removal process for decarburization or no decarburization, and a zinc process.
2.2 Flotation exploration test
A large number of exploration experiments have proved that the ore content of lead ore in this ore is fine, and the size of zinc mineral inlay is coarse and medium unevenly embedded, which is not easy to completely dissociate; lead and zinc minerals have poor floatability and slow flotation speed. Longer flotation time is required, especially when lead is selected, lead minerals are not easily mineralized and the end point is not obvious. The use of the new agent M3 as a collector can improve the floatability of lead and zinc minerals and shorten the flotation time. The carbonaceous and secondary slime in the ore seriously interfere with the flotation process and affect the selection index of lead and zinc minerals. The high carbonaceous in the ore is good in floatability and extremely difficult to suppress. In order to reduce the carbon interference, the lead is selected before the lead. Decarburization and non-decarburization comparison test, the test results show that the grade of lead crude concentrate is basically equivalent (11.03% and 10.95%, respectively), but the recovery rate of decarbonized lead crude concentrate is better than that of non-decarburized lead coarse concentrate. It is 6.06% lower, and the carbon extracted is higher in lead and zinc (lead 4.64%, zinc 7.00%), loss lead recovery rate is 6.06%, and zinc recovery rate is 2.22%. In order to investigate the influence of decarburization on the grade of lead concentrate, and then the influence on the grade of lead concentrate after decarburization, three times of decarbonization of lead concentrate was selected, and the results of several tests were repeated. It indicates that the grade of lead concentrate is still between 27% and 37%, which does not meet the requirements of qualified products. From the simplification of the process structure and cost reduction, it is determined that there is no decarburization before lead selection; in order to further investigate the possibility of improving the grade of lead concentrate, the lead concentrate is further refined by lead concentrate, and the gangue dispersant is added. After three selections, the lead concentrate still has not reached the qualified product, so it is determined that the lead is not re-grinded and will be re-ground to the zinc-selecting circuit; the pyrite content is high, easy to float, difficult to suppress, and various inhibitors It is concluded that the use of lime to suppress pyrite is better.
By a variety of flotation agents alone, mixed probe test, to determine the final control agent selected from the group of lead lime, A3 and inhibiting mineral pyrite better zinc, zinc-adjusting agent is selected from lime still conventional, more appropriate copper sulfate, Lead and zinc are selected using the same collector M3 and foaming agent
2.3 Influence of main process parameters on flotation indicators
2.3.1 Relationship between lead rough selection index and ore grinding fineness
The fineness of the ore grinding is critical to flotation. Figure 1 shows the relationship between the crude lead selection index and the ore grinding fineness. Figure 1 shows that with the increase of grinding fineness, the lead grade of lead crude concentrate is basically the same, the lead recovery rate is increased, the zinc content is reduced, but the over-grinding will reduce the floating speed of some lead and prolong the flotation time. Therefore, it is determined that the ore grinding fineness is 88%-74μm.
Relations roughing indicators and ore fineness of grinding Figure 1 lead
1—Lead recovery rate; 2-Zn recovery rate; 3—Lead grade
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2.3.2 Relationship between zinc rough selection index and copper sulfate dosage
Figure 2 shows the relationship between the zinc rough selection index and the amount of copper sulfate. Figure 2 shows that with the increase of the amount of copper sulfate, the grade of zinc coarse concentrate decreases, and the zinc recovery rate increases, but the amount of copper sulfate increases to a certain extent, and the zinc recovery rate decreases. In order to avoid the shortage of copper sulfate, the amount of copper sulfate used is 600g/t·original.
Figure 2 Relationship between zinc coarse selection index and copper sulfate dosage
1—zinc recovery rate; 2—zinc grade
2.3.3 Effect of Re-grinding of Zinc Coarse Concentrate on Z Selective I Index
Figure 3 shows the relationship between regrind fineness of zinc coarse concentrate and monomer dissociation. Figure 3 shows that at -43μm particle size, the dissociation degree of iron sphalerite monomer is less than 90%; the monomer solution of galena and pyrite is also low, and some of the continuum affects the zinc concentrate grade. Figure 4 shows the relationship between the zinc-selected I index and the regrind of zinc concentrate. Figure 4 shows that as the regrind fineness increases, the grade of zinc concentrate increases, indicating that fine grinding is beneficial to the dissociation of zinc minerals, but the fineness increases to a certain extent, and the floatability of some zinc deteriorates. The floating time is extended. Considering comprehensively, it is determined that the regrind fineness is 95%-43μm.
FIG 3 zinc rougher concentrate and then pulverized with a monomer solution of degrees from the relationship
Diagram 4 Zinc concentration â… Index and zinc rougher concentrate is re-ground of
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2.4 closed circuit test
On the basis of the conditional test, the closed-circuit test appropriately adjusted some of the agents. In order to reduce the influence of lead, carbon and slime on the quality of zinc concentrate and ensure the recovery rate of zinc concentrate, most of the carbon and secondary slime should be selected into lead concentrate as much as possible when lead is selected. Selected to reduce the loss of zinc in lead concentrates. The closed-circuit test process is shown in Figure 5. The results are shown in Table 2. Then, according to the flow of Figure 6, the closed-circuit test of the lead-mineral re-grinding is returned to the rough selection. The results are shown in Table 2.
Figure 5 Zinc coarse concentrate re-blind closed circuit test process
Table 2 Closed circuit test results /%
Program | product name | Yield | Grade | Recovery rate | ||
Pb | Zn | Pb | Zn | |||
Zinc coarse concentrate Regrind | Lead concentrate Zinc concentrate Tailings Raw ore | 7.53 17.16 75.31 100.0 | 20.20 1.18 0.85 2.36 | 5.86 46.89 1.35 9.50 | 64.35 8.57 27.08 100.0 | 4.64 84.66 10.70 100.0 |
Zinc mine Regrind | Lead concentrate Zinc concentrate Tailings Raw ore | 7.48 16.77 75.75 100.0 | 20.79 1.00 0.91 2.41 | 5.95 47.61 1.40 9.49 | 64.47 6.95 28.58 100.0 | 4.69 84.13 11.18 100.0 |
Figure 6 Zinc mine re-grinding return zinc rough selection closed-circuit test process
According to the test results, the zinc coarse concentrate re-grinding and the zinc-mineral re-grinding are returned to the zinc rough selection. The two process indexes are equivalent, but the former process is unstable, which is reflected in the large amount of grinding; The floating speed of zinc minerals is slower and the flotation time is prolonged; the zinc minerals are easily lost in the selection; the consumption of zinc rough selection and selected copper sulfate is greater than that of the condition test. The latter overcomes the above deficiencies and the operation is stable. Therefore, it is recommended that the re-grinding of zinc ore will return to the process of zinc rough selection as the technical basis for the production of the concentrator.
3 re-election
According to the difference of various mineral densities, the zinc-mineral re-grinding and returning to the closed-circuit test product high-carbon lead concentrate of zinc rough selection directly subjected to shaker re-election to investigate the possibility of producing qualified lead concentrate. Table 3 shows the results of the shaker sorting test. It can be seen from the results in Table 3 that the low-grade lead concentrate obtained by flotation can be used to produce a partially qualified concentrate with a lead grade of 58.43% by shaker separation. The low recovery rate of the operation is due to the fine grain size of the lead mineral, limited by the fineness of the grinding, the low degree of dissociation of the monomer, and the partial birth of the lead into the middle and tailings. The flotation lead concentrate can be reground first if the site conditions permit. If the site conditions permit, the flotation lead concentrate can be re-grinded first to further improve the lead concentrate recovery rate.
Table 3 Shaker Sorting Test Results /%
product name | operation Yield | Grade | Job recovery rate | ||
Pb | Zn | Pb | Zn | ||
Lead concentrate Medium mine Tailings Give mine | 14.47 61.95 23.58 100.0 | 58.43 13.33 14.67 20.17 | 3.91 7.07 6.25 6.42 | 41.91 40.94 17.15 100.0 | 8.81 68.23 22.96 100.0 |
4 Conclusion
1. Exploratory test results show that the lead and zinc minerals of the ore are poorly floatable and the floating speed is slow. The collector M3 can improve the floatability of lead and zinc minerals; some lead and zinc minerals have finer grain size due to the inclusion. Fine grinding is required, but the grinding fineness does not reach the complete dissociation of the monomer, which affects the improvement of lead and zinc concentrate grade; the high carbon and secondary slime in the ore seriously interfere with the floating At the same time, the oil consumption of the whole flotation process is large. In order to reduce the influence of carbonaceous, some of the easily floatable carbonaceous materials are preferentially selected into lead concentrates with lead; the high-sulfur iron ore in the ore is easy to float and is difficult to suppress. In comparison, it is better to use lime to suppress.
2. The flotation test finally determines that the raw ore is ground to 88%-74μm. Under the condition of lime medium, adjuster A3, collector M3 and pine oil are added to select lead. The lead concentrate is selected three times. High-carbon lead concentrate; lead-type tailings were added with lime, copper sulfate, M3 and pine oil to select zinc, and closed-circuit tests were carried out on the two processes of zinc coarse concentrate re-grinding and medium-mine re-grinding, respectively. The zinc grade of zinc concentrate is about 47%, and the zinc recovery rate is better than 84%, but the flotation lead concentrate has not obtained qualified products. The indicators of the two schemes are equivalent, but the process of returning zinc to the zinc after re-grinding is reasonable, the grinding amount is small, and the operation is convenient. It is recommended as the technical basis for the production of the concentrator.
3. In order to investigate the possibility of producing qualified lead concentrate, the high-carbon lead concentrate of the flotation closed-circuit product was subjected to shaker re-election to obtain a partial lead concentrate of 58.43% of lead grade. This measure can be used as a technical reserve for the recovery of some lead minerals by the concentrator in the future.
4. The newly developed regulator A3 has a strong inhibitory effect on the easy-to-float zinc minerals and pyrite, and has a certain activation effect on lead minerals; the collector M3 has strong ability to capture lead and zinc minerals. Good, and can improve the flotation speed of lead and zinc minerals and improve the state of flotation foam. The preparation of the two medicaments has a wide source of sources, is non-toxic, tasteless, and is easily soluble in water, and is convenient to add on site.
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