Study on improving the flotation index of polymetallic lead sulphide ore

Lead zinc ore Bainiuchang is a lead, zinc, silver, tin and sulfur symbiotic large multi-metal sulfide ore. Mine ore reserves, for recovered metal, high economic value, but the fine particle size mineral incrustation, the oxidation rate of the ore, is a hard mineral stone, especially arsenic, lead and zinc and sulfur separation difficult. At present, there is a medium-sized concentrating plant with a daily processing capacity of 1800t. The grade and recovery rate of lead and zinc concentrate in on-site production has a certain distance from the lead and zinc beneficiation index in the month. Improving the quality and recovery rate of concentrates is of great significance to improve the economic benefits of the concentrator.

First, the nature of the ore

The complex composition of ore minerals, there are mainly useful minerals pyrite, sphalerite and iron sphalerite, galena, antimonial lead, tin Hui galena, cassiterite and arsenopyrite and the like. Gangue minerals are quartz, dolomite, sericite, iron, manganese and manganese calcite calcite. The mineral composition and content of raw ore are shown in Table 1. The chemical analysis results of the ore are shown in Table 2.

Table 1 Mineral composition and content of ore

Table 2 Multi-element analysis results of raw ore %

Embedding characteristics of major minerals

Galena: Galena contains an average of 86.3% lead and 13.7% sulfur. The galena is in the shape of granules, veins alone or in combination with sulphide ore and iron sphalerite in the interstices and fissures of pyrite particles, or in the form of fine particles and fine particles impregnated in iron sphalerite and veins. In stone minerals. Galena often has sulphide lead ore, sphalerite, bismuth tin ore and bismuth lead silver ore inclusions. The galena content has a grain size of 0.4 to 0.003 mm.

Thiophene lead ore: Huixi tin-lead ore contains an average of 54.49% lead, 11.68%, 10.78% tin and 20.75% sulfur. The stibnite tin ore is a fibrous aggregate that is embedded in the iron sphalerite and gangue alone or in combination with sulphide ore, sometimes with pyrite and cassiterite inclusions. The embedding grain size of the bismuth tin ore is 0.1 to 0.007 mm.

Iron sphalerite and sphalerite: The iron sphalerite contains an average of 56.60% zinc, 33.27% sulfur, 10.00% iron and 0.13% copper . The iron sphalerite and sphalerite are often in the form of granules alone or in combination with galena and sulphide ore in the fissures of pyrite and pyrite or embedded in the gangue. In the iron sphalerite and sphalerite, there are often inclusions of granular galena, pyrite, arsenopyrite, sulphide ore, cassiterite and chalcopyrite. The iron sphalerite and sphalerite have an inlaid particle size of 0.6 to 0.005 mm, iron sphalerite of about 70%, and sphalerite of about 30%.

Pyrite: Includes a small amount of pyrrhotite and a small amount of pyrite. The pyrite contains an average of 47.12% iron and 52.88% sulfur. The pyrite is self-shaped semi-automorphic crystal embedded in the gangue. Common galena, iron sphalerite and sulphide ore are packed in the gaps or fissures of pyrite and sphalerite particles. The inlaid particle size of pyrite is 0.8 to 0.01 mm.

Aromatic sand: The poisonous sand contains an average of 42.19% arsenic, 34.96% iron, 22.55% sulfur and 0.3% zinc. The arsenopyrite is in the shape of a self-formed grain or embedded in the iron sphalerite or gangue with the pyrite. The incineration particle size of the arsenopyrite is 0.07 to 0.005 mm.

Second, the mineral processing test

(1) Grinding fineness test

The full dissociation of lead and zinc mineral monomers is the basic condition for the separation of lead and zinc and the improvement of lead and zinc quality and recovery. The relationship between lead and zinc recovery and grinding fineness is shown in Figure 1.

It can be seen from Fig. 1 that when the fineness of the grinding is more than 68%-74 μm, the recovery rate of lead and zinc does not increase much as the fineness of the grinding fineness decreases. According to the process of the production site, the fineness of grinding is determined to be -74μm, accounting for 68%.

(2) Collector test

1. Collector test

In the collector type test, the test procedure for selecting butyl xanthate and ethyl sulfide nitrogen is shown in Figure 2. The test results are shown in Table 3.

Table 3 Collector type test results /%

The test results show that the butyl xanthate has a strong ability to capture lead, zinc and silver, but the lead concentrate has a low grade and a high zinc content. The selectivity of ethyl sulphide is good, the grade of lead concentrate is higher, and the content of zinc is lower. Therefore, lead flotation is a mixture of butyl xanthate and ethyl sulphide combined collector.

2, mixed collector dosage test

The test flow chart is shown in Figure 2, and the test results are shown in Table 4.

Table 4 Mixed collector dosage test results /%

It can be seen from Table 4 that the higher the proportion of butyl xanthate in the mixed collector, the higher the yield of lead concentrate, the lower the lead grade, and the higher the recovery rate of lead and zinc. The higher the proportion of ethyl sulfide in the mixed collector, the higher the grade of lead concentrate and silver, and the lower the zinc recovery rate. The final dosage of butyl xanthate and ethyl sulphide was determined as follows: lead crude selection I was: 60 g/t+60 g/t, and lead crude selection II was: 60 g/t+60 g/t.

(III) Selection and dosage test of zinc-sulfur inhibitor

The pyrite-free pyrrhotite and a small amount of planktonic pyrite are the main reasons for the low grade and recovery of lead and zinc concentrates in production. The use of combination inhibitors has had little effect. The inhibition of pyrrhotite and pyrite has become a major problem in production. According to the theory of potential-controlled flotation, different minerals have different flotation potentials, and the potential of the slurry is adjusted to a certain extent, so that the lead floats, the pyrite, the pyrrhotite and the zinc mineral are suppressed, and the separation is achieved. the goal of. This test uses lime as a regulator of the slurry potential.

1. Lime dosage test

The lime dosage test procedure is shown in Figure 3, and the test results are shown in Table 5.

Table 5 Lime dosage test results /%

It can be seen from Table 5 that with the increase of the amount of lime, the grade of lead concentrate is gradually increased, the grade and recovery rate of zinc and sulfur are both reduced, and the amount of lime is preferably 5000g/t.

(IV) Zinc flotation agent dosage test

In the high alkali process, after the float is preferentially floated, the flotation of zinc can be sequentially performed. When flotation of zinc minerals, the pyrite and pyrrhotite of the pulp have been strongly inhibited, using copper sulfate as the activator for the flotation of zinc minerals and butyl xanthate as the collector. See Figure 4 and the test results are shown in Table 6.

Table 6 Collector, test results /%

It can be seen from Table 6 that when the amount of butyl yellow is up to 100 g/t, the zinc recovery rate is 93.37% while ensuring the grade of zinc rough concentrate. The amount of butyl yellow was determined to be 100 g/t crude.

(5) Closed circuit test

The closed circuit test was carried out according to the test conditions determined for each individual item. The test results are shown in Table 7.

Table 7 Closed circuit test results /%

It can be seen from Table 7 that lead concentrate has a decrease in zinc and an increase in the grade of lead and zinc concentrate.

Third, production practice

According to the results of the experimental research, industrial tests are carried out in the production workshop, and after some technical parameters are fine-tuned, industrial production is carried out. After the implementation of the new process, the grade of lead concentrate increased by 9.95%, the zinc content of lead concentrate decreased by 4.2%, the grade of zinc concentrate increased by 1.88%, and the recovery rate of zinc increased by 6.63%, achieving the goal of improving the lead and zinc beneficiation index. See Table 8 for comparison of production indicators before and after the implementation of the new process.

Fourth, economic benefits

Table 8 Comparison of production indicators before and after the implementation of new process /%

After adopting the new process, the production process is simplified, and the pharmaceutical system for lead flotation operation is simple and clear, reducing the types and dosages of the chemicals, reducing the cost of the chemicals, and facilitating production management. From August to December, due to the improvement of mineral processing indicators and the decline of mineral processing fees, the concentrating plant created a total benefit of 4.269 million yuan.

V. Conclusion

(1) Through the study on the flotation behavior of galena, sphalerite and pyrite in high alkaline low oxidation potential medium and its separation conditions and chemical system, it is proposed to deal with the complex lead-zinc sulfide ore potential of Bainiuchang. Control the new flotation process. Adding the adjusting agent lime and the collector ethionous nitrogen and butyl xanthate to the grinding machine at the same time, fully utilizing the regulation and stabilization of the slurry potential by lime, and the sulphur-nitrogen to the mineral under the low oxidation-reduction potential caused by lime Select the harvesting effect to achieve efficient separation of lead, zinc and iron.

(2) The new pharmaceutical system and process have achieved success in actual production, achieving the purpose of reducing zinc in lead concentrate and improving the quality of lead and zinc concentrate and zinc recovery. The lead concentrate grade increased by 9.95% to 53.19%, the recovery rate increased by 1.5% to approximately 93.32%, the zinc concentrate grade increased by 1.88% to 41.20%, and the zinc recovery rate increased by 6.63% to approximately 88.36%.

(3) The separation of sulfur and arsenic is difficult, and the successful separation of sulfur and arsenic will be another highlight of the company's efficiency.

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