Fankou lead zinc mines come on stream in 1968, has now become an annual ore processing 1.2 million t, lead and zinc metal production of 150,000 t, standard sulfur concentrate (equivalent to) large and Zinc Mine of 500,000 t. Fankou ore beneficiation plant in the production of construction and development process, relying on mineral processing technology advances, has used over a dozen process, the main system were in 2000 and 2001 using a rapid branch flotation process, the production capacity of 2050t are /d.
First, test the ore sample
Ore Fankou main types of lead-zinc complex sulphide form a dense, metallic minerals mainly galena, sphalerite, pyrite content of about 60% (where pyrite content of up to 40%); Silver Minerals tetrahedrite ore predominantly silver and copper, silver magenta, was associated in the lead-zinc; gangue minerals as quartz, calcite and dolomite. The symbiotic relationship of various minerals is very close, and the dissolution and metasomatism is more serious. The fine galena is filled in the gaps or fissures of pyrite, sphalerite and gangue minerals. The ore lead, sphalerite and pyrite in the ore are unevenly intercalated with medium and fine particles, and some of the pyrite have better planktonic activity, which is a difficult-to-select fine-grained high-sulfur lead-zinc ore.
The test ore sample of this project is taken from the transportation belt in front of the powder ore bin of the ore dressing plant. It is synchronous with the original ore produced at that time. The particle size is -15mm. The main elements are lead 4.75%, zinc 9.85%, iron 22.25% and sulfur 27.35%.
Second, rapid branch flotation process research
(1) Research ideas
According to the close symbiosis of galena, sphalerite and pyrite in Fankou lead-zinc ore, the grain size of the inlay is not uniform. When the ore is milled to -74μm, 85%, the useful minerals have dissociated most of the monomers. Quickly sort out most of the coarse-grained, easily floating lead-zinc metal minerals in a short period of time to obtain high-quality lead concentrates and zinc concentrates, reducing excessive pulverization and unnecessary circulation of dissociated minerals. The remaining lead-zinc minerals are recovered by conventional flotation, and the re-grinding of the refinery is enhanced to increase the dissociation degree of the monomer, so as to reduce the total volume of the flotation machine, reduce the production cost, and improve the recovery rate of lead-zinc metal.
(2) Test of the floating speed of lead and zinc minerals
1. Galvanic speed test of galena
The test raw ore is ground to a fineness of -74μm, accounting for 85%, adding lime as the pH adjuster for the pulp, FK01 as the collector, and the pine oil as the foaming agent, the amount of lime, the amount of FK01, the amount of pine oil After the condition test determines the pharmaceutical system, the lead rough flotation speed test is carried out to determine the floating speed of different galena particles (see Figure 1 for the test flow and Figure 2 for the results).
The test results show that the floatability of most lead minerals is very good. The recovery rate of lead-smelting concentrate is 71.72% and the grade is 29.10%. The recovery rate of scraping 2min is as high as 84.16% and the grade is decreased to 24.24%. With the extension of flotation time, the lead grade continued to decline, the zinc and iron grades increased, and the lead metal recovery rate slowed down. The recovery rate of lead for cracking for 5 min was 91.10% and the grade was 17.72%. The test also shows that the lead floatability is the best under high alkali conditions, the floatability of pyrite is second, the floatation speed of some pyrite is faster, and the floatability of unactivated sphalerite is the worst.
2. Sphalerite speed up test
The lead tailings are supplemented with lime 1000g/t, CuSO 4 is used as the activator, butyl xanthate is used as the collector, and the pine alcohol oil is used as the foaming agent. After determining the pharmaceutical system by the amount of CuSO 4, the amount of butyl yellow and the amount of pine oil, the zinc rough flotation speed test was carried out to determine the floating speed of different sphalerite particles (the test results are shown in Fig. 3).
The test shows that most of the sphalerite has good floatability. The recovery rate of the 1min zinc concentrate is about 50.63% and the grade is up to 51.30%. The recovery rate of the 2min is up to 65.45% and the grade is 50.51%. Maintaining above 50%; with the extension of flotation time, the grade of zinc concentrate is flat and the recovery rate of metal continues to rise. The recovery rate of zinc for 5min is 75.18% and the grade is 45.83%.
(III) Study on branch flotation of lead minerals
1. Lead rapid flotation test
According to the relationship between lead rough selection grade and recovery rate and flotation time in Figure 2, it is determined that the flotation time of this small pilot lead rapid rough selection is 2min, and the coarse concentrate can be up to 70 after two quick selections. .55% of fast flotation lead concentrate (1.90% zinc) with a recovery of 55.59%. The test flow is shown in Figure 4.
The test also showed that different rough-selection drug systems have distinctly different selectivity in lead selection operations, and it is difficult to predict fast lead concentrate indicators through lead coarse concentrate indicators. In the rapid selection of lead, a small amount of collector is added. The grade of high-lead concentrate is decreased, and the recovery rate of lead is increased. When the amount of lime is large, the grade of lead concentrate can be improved, and the recovery rate is not changed. Big.
In addition, the organic inhibitor-DS has a strong inhibitory effect on pyrite. When the amount is increased, the grade of lead concentrate is increased. However, when the amount is too large, the lead and iron are inhibited, and the recovery rate of lead is decreased.
2. Lead conventional flotation test
After the raw ore was quickly rough-selected by 2 min lead, the conventional rough selection of lead was carried out by adding 10 g/t of FK01 for 4 min. The lead rough-selected foam contains a large amount of lead iron and lead-zinc continuum, which must be ground again to increase the degree of monomer dissociation. The fineness requirement is -40 μm, accounting for 90%. Tests have shown that under the same pharmaceutical conditions, the grade of lead-selected foam increases with the increase of regrind fineness, but too high grinding fineness will lead to a decrease in lead recovery rate.
After the lead rough-selective foam was further ground to -40 μm and accounted for 90%, a lead concentrate of 64% (containing 2.9%) was obtained by three conventional open-circuit selections, and the recovery rate was 6.69%. The test flow is shown in Figure 4.
(IV) Study on branching flotation of zinc minerals
1. Zinc rapid flotation test
According to the curve of zinc rough selection grade and recovery rate and flotation time in Fig. 3, it is determined that the flotation time of zinc rapid coarse selection in this small test is 2 min. The fast-sorting foam of zinc is generally up to 50%. It can be directly selected without any chemicals. The foam grade is up to 59.4% and the recovery rate is 37.5%. In the rapid flotation of zinc, the lime is added to 1000g/t. After a rapid selection of copper sulfate at 25g/t, although the foam grade decreased slightly, a high-quality zinc concentrate with a grade of 57.30% and a lead content of 0.66% was obtained, and the recovery rate was 48.68%. The test flow is shown in Figure 5.
Tests have shown that most of the sphalerite in the ore is easy to float. In the small closed loop, about 70% of the total metal content of zinc minerals can be produced by rapid flotation.
2. Zinc conventional flotation test
After the lead tailings were quickly and roughly selected by 2 min of zinc, 10 g/t of butyl xanthate was added for routine rough selection of zinc for 3 min. The zinc-containing rough-selected foam generally has a zinc content of about 20%. After two conventional open-circuit selections, a zinc concentrate with a grade of 55% (with a lead content of 0.95%) can be obtained, and the recovery rate is 781%. The test flow is shown in Figure 5.
The test shows that under different conditions of rapid zinc rough selection and conventional rough selection, the zinc grade of zinc selected ore has a certain fluctuation, but after two selections, the grade of the final zinc concentrate is still ideal.
(5) Open circuit and closed circuit test
On the basis of the completion of the conditional test, the subject arranged an open circuit test and conducted a closed circuit test based on the open circuit test results. Through closed-circuit test, a fast lead concentrate with a grade of 66.73% can be obtained, the recovery rate is 67.97%, the fast zinc concentrate with a grade of 56.93%, the recovery rate is 72.19%; the lead concentrate grade of the conventional flotation part is 57.18%, The recovery rate was 18.62%, the zinc concentrate grade was 54.39%, and the recovery rate was 22.55%. The test process is shown in Figure 6, and the test indicators are shown in Table 1.
Third, industrial application and results review
(1) Overview of industrial applications
After the successful experiment of the fast branch flotation process, the Fankou lead-zinc mine was semi-industrial tested from November 18, 1999 to January 12, 2000, and the main process of the concentrator was organized according to the results of the semi-industrial test. Transform the design. On February 1, 2000, the design department completed the construction drawing design for the process transformation. On February 26, 2000, the concentrator completed the system transformation task and successfully tested the water. On the morning of February 28, 2000, the concentrator I system resumed production and industrial trials began. After nearly two months of hard work, the test was a complete success.
After the industrial test is completed, the rapid branch flotation process is delivered to production. After more than three years of application and improvement, the new process has obvious advantages in improving lead and zinc index, saving energy and reducing consumption and reducing the amount of operation. The comparison between the new process and the original process production indicators is shown in Table 2.
(2) Technical and economic review
The rapid branch flotation new process comprehensively applied the experience and technical achievements of the Wankou lead-zinc mine for more than 30 years, and made innovations with reference to the latest modern beneficiation theory. Since the process was delivered to production, it has significantly improved the economic indicators of mineral processing technology, and the annual economic benefit has reached 13 million yuan.
1. Improve lead and zinc recovery rate
Compared with the original high alkali fine grinding priority flotation process, the theoretical recovery rate of lead-zinc metal in the fast branch flotation process was increased by 0.36% and 0.41%, respectively, and the lead concentrate was reduced by 0.8%. In addition, after reducing the amount of flotation operation and metal loss, the actual lead recovery rate is 0.69% and the actual zinc recovery rate is 0.35%.
2, energy saving
After the implementation of the new process, the volume of the two main system flotation machines of the concentrator decreased from 1028.8m 3 to 774.8m 3 , a decrease of 24.7%; the total installed power of the flotation machine decreased from 3144kW to 2480kW, which was reduced by 664kw. Due to the reduction of the installed power of the system and the reduction of the operating cycle load, the concentrating unit's treatment of grinding flotation power per ton of ore is reduced from 35.00 kW·h to 28.48 kW·h, which significantly saves electricity costs.
In addition, the cost of using the new process is also significantly lower than that of the original process. According to the actual consumption statistics of the concentrator, the unit cost of mineral processing decreased from 18.848 yuan/t to 14.231 yuan/t.
3. Social benefits
The significant social benefits brought about by the implementation of the fast branch flotation process are mainly reflected in the following aspects:
(1) Reducing metal loss, making full use of existing mineral resources and recycling and utilizing lead and zinc metal for the country;
(2) The decline in power consumption is conducive to alleviating the current contradiction of power supply in China;
(3) Decrease in unit consumption of pharmaceuticals is conducive to environmental protection of mining enterprises;
The f41 flotation process is shortened, which can reduce the occupation of fixed assets and help accelerate the turnover of state-owned assets.
After many years of application and implementation, the rapid branch flotation process has the advantages of advanced technology, simple process, less dosage of chemicals, high sorting index, strong adaptability to different types of lead-zinc sulfide ore, good stability and less environmental pollution. It has great promotion value at home and abroad.
V. Conclusion
(1) The galena, sphalerite and pyrite in the Fankou lead-zinc ore are closely symbiotic, the grain size of the inlaid is uneven, and some of the pyrite have better planktonic activity, which is a difficult-to-select fine-grained high-sulfur lead-zinc. mine.
(2) When the ore mill is -75μm, 85%, most of the useful minerals have been dissociated, and the coarse-grained, easy-floating lead-zinc minerals can be quickly sorted out in a short time to obtain high-quality lead concentrates and Zinc concentrate.
(3) The rapid branch flotation process is beneficial to reduce the total flotation time of useful minerals, reduce the circulation of intermediate operations, and shorten the flotation process.
(4) Industrial application shows that the fast branch flotation process effectively implements the idea of ​​being able to come out early and quickly, avoiding excessive pulverization of dissociated minerals, improving the recovery rate of lead and zinc metals, and reducing the intermediate circulation of flotation operations. Quantity, saving a lot of electricity costs and pharmaceutical costs.
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