Liu Zhibin, Zhu Congjie, Zhang Xudong, Zhang Hanping
(Yunnan Metallurgy Group Corporation Technology Center, Kunming 650031, China)
CLC number: TD952.2; TD952.3 Document code: A Â Article ID: 1671-9492 (2004) 03-0005-05
A lead-zinc mine in Yunnan has built 350 ~ 400t / d flotation plant, due to the nature of the ore changes, select Factory presence of lead concentrate grade and recovery of lead is low, higher lead concentrate zinc concentrate lead, tail Problems such as high lead and zinc content in mines are extremely unfavorable to the improvement of economic benefits. In order to explore the possibility of solving these problems, the mine is now processing ore carried out to improve the recovery of lead and zinc beneficiation process research and help lead refined zinc, zinc and lead concentrates containing impurities such as mutual problem is reduced, the characteristics of the ore properties In combination with the on-site production process, the detailed research on the preferential flotation process is focused on, and better beneficiation indicators are obtained. This article will describe the preferred flotation process.
1. Ore properties
The sample belongs to lead-zinc sulfide ore, containing lead 8.16%, lead 13.55%, silver 43.0g/t. The main useful metal minerals are sphalerite, galena, wurtzite and other sulfided lead-zinc minerals, and a small amount of mitochondria. , white lead, lead alum, calamine, and hemimorphite oxide, Pb, Zn and the like, and a small amount of yellow copper ore, pyrite and siderite and associated with a small amount of silver. Among them, sulfide minerals such as galena, sphalerite and wurtzite are the main purpose minerals for beneficiation recovery, and silver is mainly recovered with lead ore and zinc sulfide. Gangue minerals mainly calcite and quartz, mica and a small amount of white gypsum. The analysis results of chemical composition, lead phase and zinc content of raw ore are listed in Table 1, Table 2 and Table 3, respectively.
The original ore sample was investigated with an electron probe. The results showed that some lead and zinc were in the form of extremely fine-grained inlaid cloth. The combination was extremely tight and difficult to dissociate, which was extremely unfavorable for lead-zinc separation.
Table 1 Analysis results of main chemical components of ore /%
element | Zn | Pb | Ag | SiO 2 | Fe | Al 2 O 3 | CaO | S | Cu | Au | MgO | As |
content | 13.55 | 8.16 | 43.0g/t | 7.34 | 7.53 | 2.15 | 19.81 | 11.06 | 0.14 | <0.2g/t | <0.5 | 0.17 |
Table 2 Results of lead phase analysis of raw ore /%
Name | Galena | White lead ore | Lead bismuth | Lead iron and other lead | Total lead |
Lead content Distribution rate | 7.10 87.01 | 0.37 4.53 | 0.48 5.88 | 0.21 2.58 | 8.16 100.0 |
Table 3 Analysis results of raw ore zinc phase /%
Name | Zinc sulfide | Zinc carbonate | Zinc silicate | Zinc iron spinel and other zinc | Total zinc |
Zinc content Distribution rate | 12.91 95.28 | 0.26 1.92 | 0.23 1.70 | 0.15 1.10 | 13.55 100.0 |
2. Experimental study on preferential flotation process
Due to the on-site production of lead extraction by ethyl xanthate, ethyl sulphide has a strong ability to capture lead, has weaker ability to capture pyrite, has good selectivity, and has a fast flotation rate [1] . Therefore, lead extraction system The collector is made of ethyl sulphide. The foaming agent is 730A [2] which is beneficial to the separation of lead sulphide ore produced by Kunming Metallurgical Research Institute, in order to improve the selectivity, optimize the working conditions and improve the flotation effect.
2.1 Selection of lead, sweeping inhibitors, zinc sulfate and sodium sulfite
Zinc sulphate is the most commonly used inhibitor of sphalerite. It can be used for sphalerite which is not activated by copper ions, but it can only work in alkaline medium, and the higher the pH value of the pulp, the more obvious the inhibition. When zinc sulphate is used alone, the effect is not good, so it is often used in combination with other inhibitors such as sulfites [3] . The effect of the amount of zinc sulfate and sodium sulfite on the selection index is shown in Figure 1. Grinding fineness -74μm accounted for 75%, and the amount of sodium sulfite used in each operation was 1/2 of the amount of zinc sulfate used.
Figure 1 Effect of the amount of zinc sulphate and sodium sulfite on the sorting index
1- lead concentrate contains lead grade; 2- lead concentrate contains zinc grade; 3- lead concentrate lead recovery rate 4- lead loss in lead concentrate; the same below.
The results show that with the increase of the amount of zinc sulfate and sodium sulfite, the loss of zinc in lead concentrate and medium ore is gradually reduced, the recovery rate of lead is also decreased, and the zinc content of lead concentrate is not decreased much. Sulfuric acid and sodium sulfite Lead is also suppressed while suppressing zinc. Comprehensive comparison, the choice of zinc sulfate and sodium sulfite: coarse selection 1000 + 500g / t, sweep selection 1600 + 300g / t, sweep selection 2300 + 150g / t. [next]
2.2 Selection of lead, sweeping inhibitors, zinc sulfate and sodium sulfite
In general, it is considered that when zinc sulfate and sodium sulfite are combined to inhibit sphalerite, the ratio is optimal at 2:1, in order to further explore the influence of the ratio of zinc sulfate to sulfurous acid on the selection index, change the zinc sulfate and sub- The proportion of sulfuric acid was tested experimentally. Grinding fineness -74μm accounted for 75%, fixed amount of zinc sulfate was selected + sweep 1 + sweep 2 was 1000+600+300g/t. The effect of the ratio of zinc sulfate to sodium sulfite on the selection index is shown in Figure 2.
2.3 Lead selection of coarse selection operation adjuster sodium sulfide dosage test
Due to the presence of a small amount of white lead ore in the ore, a small amount of sodium sulfide can improve the uplift of the white lead [4] , but since the sodium sulfide has a certain inhibitory effect on the lead, it must be strictly controlled. The addition of sodium sulfide to the mill, the effect of the amount of sodium sulfide on the selection index is shown in Figure 3. Grinding fineness -74μm accounted for 75%, zinc sulfate + sodium sulfite was: 1000+1000g/t.
Figure 2 Effect of the ratio of zinc sulphate to sodium sulfite on sorting index
Fig. 3 Effect of sodium sulfide dosage on sorting index in lead roughing operation
The results show that adding a small amount of sodium sulfide can improve the lead grade of lead concentrate, reduce the amount of sodium sulfide can increase the lead grade of lead concentrate, reduce the zinc grade of lead concentrate without affecting the recovery rate of lead, and reduce The loss of zinc in the lead circuit; when the amount of sodium sulfide is too large, the recovery rate of lead is significantly reduced, while the loss of zinc in the lead concentrate does not change much. Adding an appropriate amount of sodium sulfide is beneficial to the improvement of the beneficiation index. Therefore, the amount of sodium sulfide was chosen to be 150 g/t.
2.4Selection of lead, crude and sweeping collectors
The effect of the amount of ethyl sulphide on the selection index is shown in Figure 4. The amount of sodium sulfide is 150g/t, the fineness of grinding is -74μm, which is 75%, and the amount of zinc sulfate and sodium sulfite is: 1000+1000g/t for rough selection, 1600+600g/t for sweeping, and 2300+300g/t for sweeping.
The results show that with the increase of the amount of ethyl sulfide, the lead concentrate grade decreases slightly and the recovery rate increases, and the zinc content in the lead concentrate also increases. Since the sample is low in lead and low in zinc, the amount of ethyl sulphide is selected by rough selection + sweep 1 + sweep 2 is 60 + 20 + 5 g / t.
The lead-selection operation inhibitors of zinc sulfate and sodium sulfite have little effect on the selection index. On the basis of the exploration test, the amount of zinc sulfate + sodium sulfite is selected: 1200+200g/t, 2100+100g/t, 350+50g/t .
Figure 4 Effect of lead lead and sweeping of sulphur-sulfur nitrogen on sorting index
The sphalerite which is inhibited by zinc sulfate and sodium sulfite is susceptible to activation by copper ions. Copper sulfate is generally used as an activator, and high-grade xanthate butyl sodium xanthate is used as a collector. The amount of copper sulfate was determined by experiment: rough selection + sweep 1 + sweep 2 was 500 + 100 + 50 g / t. The amount of butyl sodium yellow was determined by experiment: rough selection + sweep 1 + sweep 2 was 100 + 30 + 10 g / t.
The foaming agent adopts 730A which is favorable for lead-zinc separation produced by Kunming Metallurgical Research Institute. The foam has been relatively stable during the test, so no separate dosage test was conducted. [next]
2.5 Small closed circuit test under different grinding fineness
In order to investigate the influence of grinding fineness on beneficiation index, small closed-circuit test of different grinding fineness, combined with on-site production process, the small closed-circuit test process is shown in Figure 5. The effect of grinding fineness on the selection index is shown in the table. 4.
Table 4 Sorting index/% of small-scale closed-circuit test for different grinding fineness
Grinding fineness /-74μm | product name | Yield | grade | Recovery rate | ||||
lead | Zinc | Silver (g·t -1 ) | lead | Zinc | silver | |||
65 | Lead concentrate Zinc concentrate Tailings Raw ore | 12.90 22.92 64.18 100.0 | 52.65 3.10 0.98 8.13 | 9.06 50.32 1.10 13.41 | 185.2 38.5 17.3 43.8 | 83.53 8.74 7.73 100.0 | 8.72 86.01 5.27 100.0 | 54.55 20.12 25.33 100.0 |
75 | Lead concentrate Zinc concentrate Tailings Raw ore | 12.94 22.71 64.35 100.0 | 53.36 2.64 0.94 8.11 | 8.65 50.83 0.93 13.26 | 192.0 43.2 13.0 43.0 | 85.14 7.39 7.47 100.0 | 8.44 87.05 4.51 100.0 | 57.78 22.82 19.40 100.0 |
85 | Lead concentrate Zinc concentrate Tailings Raw ore | 13.21] 22.56 64.23 100.0 | 54.97 2.32 0.83 8.32 | 8.16 51.83 0.86 13.32 | 190.0 42.9 12.8 43.0 | 87.28 6.29 6.43 100.0 | 8.09 87.78 4.13 100.0 | 58.37 22.51 19.12 100.0 |
95 | Lead concentrate Zinc concentrate Tailings Raw ore | 12.86 22.78 64.36 100.0 | 55.56 2.12 0.83 8.16 | 8.01 52.12 0.85 13.45 | 197.6 43.4 12.9 43.6 | 87.56 5.92 6.52 100.0 | 7.66 88.28 4.06 100.0 | 58.28 22.68 19.04 100.0 |
The results show that with the improvement of grinding fineness, the copper lead grade and recovery rate of lead concentrate are continuously improved, the zinc content of lead concentrate is reduced, and the recovery rate of silver in lead concentrate is also improved; zinc grade of zinc concentrate is The recovery rate has also increased, and the lead content of zinc concentrate has been reduced. In summary, improving the fineness of grinding is conducive to the improvement of mineral processing index.
3 Discussion
The original ore sample belongs to lead-zinc ore sulfide, containing lead 8.16%, zinc 13.55%, silver 43.0g/t, lead sulfide accounting for 87.01% of total lead, and zinc sulfide accounting for 95.28% of total zinc. It is the main target mineral for ore recovery, silver. As the concentrate is recycled, the lead oxide content is high (up to 12.99%). The original ore sample was investigated with an electron probe. The results showed that some lead and zinc were in the form of extremely fine-grained inlaid cloth. The combination was extremely tight and difficult to dissociate, which was extremely unfavorable for lead-zinc separation. This is one of the reasons for the high mutual content of lead and zinc concentrates.
By using the priority flotation process to process the ore, a satisfactory selection index can be obtained. The results of the small closed-circuit test were compared with the on-site production indicators at the time (see Table 5):
(1) Small closed-circuit test lead concentrate contains lead (up to 50%) and recovery rate (about 87%) has a large increase (grade increase of about 8%, recovery rate increased by about 10%), lead concentrate The recovery rate of BOC also increased significantly (about 6...%).
(2) The grade of zinc concentrate is close and the recovery rate is slightly improved (recovery rate is increased by about 2%), and the lead content of zinc concentrate is significantly reduced (from 3.14% to 2.32%).
(3) The lead and zinc grades in tailings are significantly reduced, and the amount of lead and zinc metal lost in tailings is greatly reduced, which significantly improves the recovery rate of lead and zinc beneficiation.
Table 5 Comparison of small closed-circuit test indicators and on-site production indicators at the time /%
Grinding fineness /-74μm | product name | Yield | grade | Recovery rate | ||||
lead | Zinc | Silver (g·t -1 ) | lead | Zinc | silver | |||
85 (test indicators) | Lead concentrate Zinc concentrate Tailings Raw ore | 13.21 22.56 64.23 100.0 | 54.97 2.32 0.83 8.32 | 8.16 51.83 0.86 13.32 | 190.0 42.9 12.8 43.0 | 87.28 6.29 6.43 100.0 | 8.09 87.78 4.13 100.0 | 58.37 22.51 19.12 100.0 |
70 to 75 (production index) | Lead concentrate Zinc concentrate Tailings Raw ore | 13.02 22.26 64.72 100.0 | 46.62 3.14 1.76 7.91 | 8.24 50.26 1.23 13.06 | 173.6 41.4 17.2 43.0 | 76.75 8.84 14.41 100.0 | 8.21 85.67 6.12 100.0 | 52.26 21.43 26.01 100.0 |
Figure 5 Small closed circuit test procedure for different grinding fineness
The research results show that the test has achieved certain results mainly because:
(1) Ensure sufficient fineness. Increasing the fineness of grinding is conducive to the improvement of mineral processing indicators. [next]
(2) Improve the agent addition system of the modifier. The addition of sodium sulfite has a great influence on the effect of zinc inhibition. The effect of using only zinc sulfate to inhibit sphalerite is poor. With the increase of the amount of sodium sulfite, the total recovery of lead does not change much, and the loss of zinc in the lead circuit Significantly reduced, the effect of zinc inhibition is better when the ratio of zinc sulfate to sodium sulfite is 1:1. Adding an appropriate amount of sodium sulfide to the mill can increase the lead grade of the lead concentrate, reduce the zinc grade of the lead concentrate without affecting the lead recovery rate, and reduce the loss of zinc in the lead circuit.
(3) The lead-selecting agent adopts the selective selectivity of ethylsulfide nitrogen, which can reduce the influence of the ore-mining amount and fluctuation of the dosage of the flotation process on the selection index, which is conducive to the improvement of the beneficiation index.
From the research results, the problem to be solved in the research is to conduct more in-depth research on reducing the mutual inclusion of concentrates and further increasing the recovery rate of zinc concentrate zinc.
(1) In view of the current problem of low lead concentrate grade and recovery rate and high lead and zinc in tailings, it is recommended to investigate the current production process to further identify the reasons.
(2) The process and system for ensuring the full dissociation of lead and zinc are to be further studied.
references
[1] Hu Weibai, flotation (revised edition) [M]. Beijing: Metallurgical Industry Press, 1989, 89.
[2] Yu Yunbai, Research and practice of foaming agent 730A in the classification of lead-zinc sulfide ore [J], Non-Ferrous Metals (Mineral Processing), 2002, (4): 37-38.
[3] Hu Xigeng, Non-ferrous metal sulfide ore dressing [M], Beijing: Metallurgical Industry Press, 1987, 196.
[4] Shi Daomin, Yang Wei, Flotation of lead oxide zinc ore [M], Kunming: Yunnan Science and Technology Press, 1996, 22.
THE RESEARCH ON BENEFICIATING PROCESS FOR
RAISING RECOVERY OF CERTAIN Pb-Zn MINE IN YUNNAN PROVINE
LIU Zhi –bin ,ZHU Cong-jie ,ZHANG Xu-dong,ZHANG Han-ping
(The Technical Center of Yunnan Metallurgical Group Co., Kunming 650031, China)
ABSTRACT
The research results show that the separation indices by using selective flotation flowsheet in certain lead-zinc mine yn Yunnan province, are more satisfied compared with the existing peration process. The grade and recovery of lead-concentrate gained from small batch closd-circuit test can Be raised 8%and 10% respectively. The grade of lead-concentrate is more than50% , and the recovery87% or so.Moreover,the recovery of silver enriched in lead-concentrate is also raised about 6%.In the condition of keeping The similar grade of zincconcentrate,the zinc recovery can beraised about2%.Therefore,the quantity of lead and zinc losed yn tailingsis substantially reduced.
KEY WORDS: lead-zinc sulfide ore;selective flotation;sodium sulfite;fine grinding
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