Study on Beneficiation Process Technology of Low-grade Lead-zinc Ore Containing Copper

A low grade lead-containing copper-zinc ore, lead, zinc, copper, gold, silver grade were 0.95%, 3.95%, 0.11% , 0.04g / t, 20.39g / t. Lead-zinc was used to preferentially flotation process. The beneficiation index obtained by laboratory closed-circuit test was: lead grade 61.65%, silver 949g/t, lead recovery 85.44%, silver recovery 62.38%; zinc concentrate The zinc grade is 48.09% and the zinc recovery rate is 90.40%.

First, the nature of the ore

(1) Analysis of main chemical components of raw ore and phase analysis

The main chemical composition analysis of the ore is shown in Table 1. The lead and zinc phase analysis results are shown in Table 2 and Table 3, respectively.

(2) Mineral composition

Lead, zinc, copper, tin , sulfur, iron , manganese and other elements in the ore are mainly present as independent minerals. Independent minerals zinc iron sphalerite; lead minerals are galena, occasionally antimonial lead, lead alum; primary copper minerals chalcopyrite, chalcocite occasionally. The main gangue minerals are quartz , calcite and dolomite.

(3) Embedding characteristics of main metal minerals in ore

The size of the main metal minerals in the ore is uneven, and the sphalerite is coarser. The granules of the galena and chalcopyrite are relatively fine. In the range of +0.074mm, the distribution rate of sphalerite is 92.00%. The distribution rate of pyrrhotite, pyrite, and pyrite is 86.72%, while the distribution rates of galena and chalcopyrite in this fraction are only 72.62% and 56.48%, respectively. In the -0.010mm grain size, the distribution rate of sphalerite is 0.24%, and the distribution rate of pyrrhotite, pyrite, and pyrite is 0.54%. The distribution rate of chalcopyrite is 2.54%, while the distribution rate of galena is 9.46%. The silver minerals in the ore are mainly distributed in lead minerals and closely related to the embedding of lead minerals.

Second, mineral processing technology research

(1) Lead coarse lime selection test

The raw ore milled to -0.074mm accounted for 70%, and the lead was coarsely selected to add zinc sulphate and yttrium sulphate. The rough lime selection test procedure was twice rough selection, and the test results are shown in Fig. 1. The results show that with the increase of lime dosage, the lead grade in lead crude concentrate gradually increases, but when the lime dosage is increased to 1500g/t, the lead recovery rate decreases significantly. It is indicated that the higher pH value has an inhibitory effect on lead minerals, so it is determined that the amount of lime is 1000 g/t.

(2) Type test of collector

The test results of the lead collector type are shown in Table 4. The results showed that the lead flotation was carried out by using the yellow syrup as the collector. The lead concentrate and the recovery rate of the obtained lead concentrate were the highest. Therefore, the yellow yam was used as the collector.

(III) Trial of lead flotation zinc sulfate

Zinc sulfate is an effective inhibitor of zinc minerals during lead flotation. The zinc sulfate dosage test was carried out under the conditions of coarsely adding lime 1000 g/t and xanthate 80 g/t, and the test results are shown in Fig. 2. With the increase of the amount of zinc sulfate, the zinc content in the lead concentrate is gradually reduced. When the amount of zinc sulfate is 1000g/t, the zinc content of the lead concentrate is 5.38%, and when the amount of zinc sulfate is increased, the lead is coarse. The lead recovery rate in the mine also decreased, indicating that some lead minerals are associated with zinc minerals, and lead minerals are also inhibited as zinc minerals are inhibited. For comprehensive consideration, a suitable amount of zinc sulfate is preferably 1000 g/t.

(4) Grinding fineness test

The results of the fineness test of lead rough selection grinding are shown in Fig. 3. As the fineness of the grinding increases, the selective recovery of lead increases. Use -0.074mm to account for 70% of the grinding fineness.

(5) Zinc coarse selection lime dosage test

The zinc rough selection process is two rough selections, and the ore is a lead flotation tailings. Under the conditions of 200 g/t of copper sulfate and 60 g/t of diced yellow sulphate, the test results of zinc coarse selection of lime are shown in Fig. 4. The addition of lime and zinc concentrate quality has been improved. Since the zinc mineral in the ore is mainly iron sphalerite, the amount of lime should not be too large, and the amount of lime used for roughing of zinc is 4000g/t.

(6) Zinc crude selection of copper sulfate dosage test

Lead sulphate is a commonly used activator in zinc flotation. The test results of copper sulfate dosage are shown in Fig. 5/ With the increase of the amount of copper sulphate, the zinc recovery rate is greatly increased. When the amount of lead sulfate is 200g/t, the tailings zinc has been reduced to 0.15%, and the amount of copper sulfate is 200g/t.

(7) Closed circuit test

The closed-circuit test is carried out by using lead and zinc in a preferred flotation process. Lead is used in two rough selections, three selections, two sweeps, and a coarse concentrate regrind process; the zinc loop uses two rough selections - three selections - two sweeps. The test results are shown in Table 5.

(8) Reducing copper content in lead concentrate

The lead concentrate contained 3.73% copper, which affects the quality of lead concentrate. To this end, a lead-copper separation test bleach inhibitors, potassium permanganate, cyanide, sulfite + starch, heavy chromate method and the like, but in addition can be obtained using the method dichromate outer high separation efficiency Other separation methods are not effective.

After detoxification of activated carbon, the combination of water glass + CMC + potassium dichromate combined inhibitor can obtain copper grade of copper conglomerate 28.67%, lead 1.21%, copper recovery rate 49.23%; lead concentrate lead grade 72.33%, including Copper 0.20%, lead recovery rate of 94.31%.

Third, the conclusion

(1) The copper-containing low-grade lead-zinc mine can obtain lead concentrate by lead-zinc followed by flotation process: lead grade 61.65%, copper-containing 3.73%, zinc-containing 1.77%, silver-containing 979g/t, lead recovery rate 85.44%, silver recovery rate of 62.38%; zinc concentrate: zinc grade 48.09%, zinc recovery rate of 90.40%.

(2) In order to improve the quality of lead concentrate, the combination of water glass + CMC + potassium dichromate can effectively reduce the copper content in lead concentrate and comprehensively recover copper.

references

[1] Wang Dianzuo. Mineral flotation and flotation reagents [M]. Changsha: Central South University of Technology Press, 1986.

[2] Hu Weibai. Flotation [M]. Beijing: Metallurgical Industry Press, 1989.

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