Experimental study on copper recovery and associated gold and silver in flotation of tailings from a copper ore separation project in a copper mine

ASHELE copper mine is a large pyrite type copper, zinc multi-metal mine, the mine in October 2004 the completion of daily processing of copper and zinc 4000t ore beneficiation plant, beneficiation process after several years of production practice, technology research And after the transformation, the flotation column has been formed to give priority to the floating copper-flotation tank. The quick-priority float copper-mixed flotation-mixed coarse concentrate re-grinding-copper-zinc separation flotation column rapid float copper-copper-zinc separation-middle mine Selective re-grinding-zinc-sulfur separation combined with the actual process flow on site, the ore grade is high, and the technical indicators directly affect the economic benefits of the enterprise. Therefore, the re-election of tailings resources as secondary resources is increasingly subject to the enterprise's It is highly valued that the company has carried out small-scale experiments in the laboratory of re-election of copper for the tailings, re-selection of tailings and re-selection of copper. The results are not good, the enrichment ratio is poor, and the recovery rate is low.

The concentration of zinc tailings in the separation of zinc and sulfur in the Ashele copper mine in Xinjiang is about 18%, the fineness of -45μm is about 95%, the dissociation degree of chalcopyrite is about 88%, and the dissociation degree of sphalerite is about 87%. . Zinc tailings contain 0.5% to 1.5% of copper, 0.5% to 1.3% of zinc, 0.18 to 0.35 g/t of gold, and 18 to 30 g/t of silver . From the above conditions, zinc tailings are available as secondary Resources for the re-election of copper, gold, silver and other valuable elements. Strengthening the recycling of this part of copper and associated gold and silver resources is valued. It is of great significance to explore whether some tailings resources can be realized as secondary resources for re-election of useful minerals such as copper and associated gold and silver. If copper and zinc

The separation of tailings containing copper is 0.8%, the zinc tailings yield is 12%, and the daily processing metal amount is 4000t. The copper lost from the zinc tailings is 3.84t per day, and the gold and silver will also be lost. This part of copper and associated recovery will be strengthened. Gold and silver can significantly improve the technical indicators and economic benefits of enterprises, while avoiding waste of resources and promoting the cyclical development of the mining economy.

1. Zinc-sulfur separation tailings ore properties

The mineral composition of zinc tailings is shown in Table 1. Pyrite is the main metal sulfide in zinc-sulfur separation tailings, which is mainly irregular, followed by self-shaped and semi-self-shaped structures. Chalcopyrite is the main copper-mineral structure in the zinc-sulfur separation tailings. It is mainly in the form of crystal structure. It is irregular, mainly composed of particles. Chalcopyrite and pyrite are very closely related, often coexisting with arsenic bismuth copper ore. . Sphalerite is the main zinc mineral in zinc-sulfur separation tailings, which is mainly produced in irregular shape. Sphalerite and pyrite, galena closer relationship, more than a knot in pyrite, disseminated relationship is more complex. Arsenic bismuth copper ore is a secondary copper-bearing mineral in zinc-sulfur separation tailings. Most of the aggregates are distributed together with chalcopyrite between pyrite grains or grain boundaries. The dissociation degree of chalcopyrite and sphalerite in zinc-sulfur separation tailings is about 87%. The copper and zinc minerals of these monomers are mainly lost at the fine-grain level of -lμm. The zinc and zinc minerals in the zinc-sulfur separation tailings are mainly connected with pyrite or wrapped in pyrite and copper and zinc minerals.

Table 1 Zinc-sulfur separation tailings mineral composition%

From the analysis results of single minerals of each mineral, most of the gold and silver have dissociated in the original ore mill to the monument-45μm fineness. Some gold is found in chalcopyrite and sphalerite, and pyrite is also one of the main carriers of gold. The occurrence of silver is more complicated. Chalcopyrite, beryllium copper, sphalerite and galena are the main carriers of silver. Among them, beryllium ore is higher in silver, and some silver and gold are intercalated or In secondary copper minerals, the recovery of silver depends on whether the beryllium ore enters the copper concentrate.

Second, experimental research

(1) Test of rough selection conditions

First, the rough selection condition test is carried out. The test process is one rough selection, and the rough selection time is 6 minutes. The test is to carry out the zinc-sulfur separation tailings extracted at the production site in a small flotation machine.

1. Flotation of raw ore pretreatment scheme test

In the production process, the addition of lime and high calcium to the zinc-sulfur separation operation and the inhibition of pyrite, the formation of hydrophilic hard-soluble substances on the surface to achieve inhibition, lime can also inhibit chalcopyrite, the principle is similar to pyrite. Therefore, to achieve the purity of the surface of the minerals associated with chalcopyrite and valuable elements, and to improve the monomer dissociation of useful minerals is a necessary condition for the efficient recovery of copper and associated gold and silver elements. The surface modification and the exploration test to improve the dissociation degree, that is, the pretreatment of flotation ore, the test results are shown in Table 2, because Y89 has a higher ability to capture copper and gold in the mine and other mine practices. Y89 40 g/t and BK201 8 g/t were used in this exploratory test.

Table 2 % of flotation ore pretreatment scheme test results

It can be seen from Table 2 that the re-grinding measures to achieve surface modification of useful minerals are better. After re-grinding, -45μm accounts for 97.2% and becomes -38μm for 95.8%, and the monomer dissociation degree of the target mineral is improved. It is beneficial to improve the floating performance of the target mineral, and initially determine the concentration of the grinding after thickening is 60%.

2, collector type test

In view of some basic properties of zinc-sulfur separation tailings and the pharmaceutical system used in the on-site process, the collector samples of butyl sodium xanthate, Y89 and PAC for zinc tailings re-selected copper were tested. The test results are shown in the table. 3.

Table 3 % of test results for different collector types

It can be seen from Table 3 that when the dosages of the three chemicals are the same, the Y89 index is better for the copper minerals contained in the zinc tailings, and the copper recovery rate is the highest, combined with the performance of the agent of Y89. Use high-efficiency collector Y89 when determining zinc refinement and copper and associated gold and silver.

3. Grinding time test

It can be seen from the different schemes of flotation ore pretreatment that the surface of the target mineral is modified by the thick regrind of the zinc tailings, and the monomer dissociation degree of the target mineral is further improved. Under the grinding conditions and dissociation degree, the recovery rate is the highest, and the grinding time test is carried out on the zinc tailings. The test results are shown in Fig. 1.

It can be seen from Fig. 1 that regrind is necessary, and the grinding time is preferably 3 min. In the subsequent tests, the grinding time was 3 min, and the fineness of -38 μm accounted for about 96%.

4, pH test

In the on-site process, mixed lime and zinc-sulfur separation operations were separately added with lime for slurrying and sulfur reduction. For the mineral characteristics of zinc tailings, after surface grinding, the surface minerals of the target minerals and non-target minerals were modified to different extents. The slurry can be re-pulped and sulfur-pressed by adding lime. The test results are shown in Fig. 2.

It can be seen from Fig. 2 that with the increase of the amount of lime, the copper recovery rate and grade of the copper concentrate are increasing. Considering the pH, the pH is preferably 11.70~12.00.

5, Y89 dosage test

After the initial determination of the Y89 agent, the Y89 was tested for dosage. The test results are shown in Figure 3.

Considering that this test should focus on the copper grade of copper concentrate, taking into account the various indicators, the Y89 dosage is better at 60g/t.

6, Na ₂ S0 ₃ dosage test

Considering that Na ₂ S0 ₃ and lime can jointly inhibit pyrite, and Na ₂ S0 ₃ can activate the characteristics of chalcopyrite, a different amount of Na ₂ S0 ₃ is tested for this purpose, and the test results are shown in Fig. 4.

It can be seen from Fig. 4 that Na ₂ S0 ₃ has a certain effect on inhibiting pyrite, and the activation of chalcopyrite is not obvious, and the suitable amount of Na ₂ S0 ₃ is 50 g/t.

(2) Open circuit test

On the basis of the above-mentioned conditional tests, an open circuit test was conducted on the re-selection of copper from the zinc tailings. The test procedure was a rough selection, two selections, and four sweeps. The test results are shown in Table 4.

Table 4 Open circuit test results%

It can be seen from the data in Table 4 that the open circuit test results are consistent with the results of the rough selection conditions. Since the copper grade of the sweeping II tailings and the sweeping III tailings is only 0.03%, it is initially determined to be used in the closed circuit test. Rough selection, three selections, and two sweeping processes are beneficial to ensure the copper grade of copper concentrate under the premise of ensuring recovery.

(3) Closed circuit test

Combined with the open circuit test results, the closed circuit test uses a rough selection, three selections, and two sweeping process procedures. The test results are shown in Table 5.

Table 5 % of closed circuit test results

Third, technical and economic evaluation

The economic value created by the recovery of copper is analyzed purely. The economic value created by the daily processing volume of 4000t and the zinc tailings yield of 12.314% is calculated. The daily output of copper metal is 3.037t, and its economic value is 75,925 yuan. For the price of 11789.5 yuan, the economic value created every day is 64135.5 yuan. If the economic value created by the gold and silver reaching the price of the price is added, the benefit is very significant.

Fourth, the conclusion

(1) The rough selection conditions and exploration experiments found that the zinc tailings slurry has better surface modification effect on the target mineral after regrind, the grinding time is initially determined to be 3 min, the fineness is -38 μm, accounting for 96%; Y89 is the target mineral. The collection effect is better, the dosage is 60g / t; the pH is adjusted to 11.70 ~ 12.00 is better, Na ₂ S0 ₃ can inhibit pyrite activation of chalcopyrite.

(2) Zinc-sulfur separation tailings can be obtained from flotation of 0.99% copper ore by flotation to obtain copper concentrate with copper grade of 13.78% by one rough selection, three selections and two sweeps. The enrichment ratio is 13.92, copper. The recovery rate was 62.28%, the copper concentrate was 5.13%, the gold and silver recovery rates were 10.74% and 32.01%, and the grades were 1.10g/t and 335.32g/t, respectively.

(3) According to the analysis of technical and economic benefits, the re-election of copper from zinc tailings can create better economic benefits. After calculation, the economic value created every day reaches 64135.5 yuan, which has not yet been added to the economy created by the gold and silver reaching the price. value.

(IV) Through trial research and technical and economic evaluation, it is feasible to re-select copper from tailings in the separation of zinc and sulfur in the Ashele copper mine in Xinjiang. The flocculated copper concentrate products can be distributed with the original copper concentrate products or Direct sales after passing the test, the economic benefits are significant.

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