Study on Mineral Processing Industry Application of Xiaomaoshan Silver-copper-lead-zinc Ore

XIAOMAOSHAN beneficiation plant was built in the 1970s, the initial plant design scale is 45,000 t / a. In the mid-to-late 1980s, the process and equipment were transformed, and the main building of the grinding and floating plant was built. Concentrator development to the present, has been gradually formed a scale of processing 90,000 t of lead zinc ore (daily processing capacity of 300t / d) of.

In 2005, as the lead-zinc ore in the old mining area was about to be mined, the concentrator then processed the ore in the new mining area. The old mining, the new silver-mine ore is a copper-lead-zinc multi-metal mine, sometimes up to 2% copper grade, silver sometimes up to 350g / t.

Process mineralogy studies show that the new metal mine ore minerals are mainly chalcopyrite, bornite, sphalerite, galena Silverlit bismuth-containing galena, pyrite, etc., is difficult to separate the Cu, Pb and Zn mine. According to the results of the small-scale ore dressing study of copper-lead-zinc polymetallic ore, the concentrator carried out the process transformation in early 2005, increased the copper selection operation, and modified the lead operation and zinc operation. After the process was rebuilt, the concentrator quickly entered the industrial test.

I. Industrial test ore

The shape of the ore body in the new mining area is complex, and there are many places in the rock (skarn, marble ), and the distribution of useful components is uneven. Due to the large number of mining points, the ore grade and nature vary greatly. The most prominent performance is that the mud content varies greatly from point to point. At the same time, due to the small amount of mining per unit time, it is difficult to match the site. During the industrial test, the ore grade fluctuation range is 1.5% to 2.7% for copper, 4% to 7.5% for lead, 2% to 7.5% for zinc, and 170 to 350g/t for silver. In addition, the allocation of refractory surface ore mines that have been stored for nearly one year has increased the difficulty of mineral processing.

Second, ore process mineralogical research

Process mineralogical studies of representative ores indicate that the main chemical components in the ore are oxygen, silicon, calcium, sulfur, copper, zinc, lead, silver, iron, manganese and a small amount of carbon, magnesium , sodium, potassium, aluminum, etc. The valuable elements for utilization are copper, zinc, lead and silver.

The main chemical composition analysis results of representative ores are shown in Table 1, and the chemical phase analysis results are shown in Table 2.

The ore contains 5.74% sulfur. The occupation rates of copper, lead, zinc and silver in the sulfides were 97.65%, 89.75%, 94.37% and 86.13%, respectively. The ore is less oxidized and is mainly sulfide ore.

The main metal minerals in the ore are chalcopyrite, porphyrite, lanhui copper, sphalerite, galena, silver-bearing bismuth, pyrite, magnetite, hematite, limonite. See also a small amount of antimony copper, sulphide copper ore and silver telluride ; the main gangue minerals are quartz , garnet (mainly calcium iron garnet), wollastonite , chlorite, and a small amount of calcite . dolomite.

Chalcopyrite is the most abundant copper mineral in the ore. In general, the size of the inlaid cloth is coarse, the maximum particle size can reach 200μm, most of them are between 30 and 60μm, and a small amount of fine particles (-10μm) inclusions are embedded in the sphalerite. The embedding characteristics of chalcopyrite in ore are simple. Most of the chalcopyrite is present in the gangue fissure, but some chalcopyrite is embedded in fine grain between the pyrite particles or filled with pyrite, while a small amount Inlaid in sphalerite, the dissociation of such chalcopyrite during the grinding process is very difficult.

The ore in the ore often interprets the chalcopyrite with Lanhui copper and copper blue, forming a rim structure around the chalcopyrite, forming a collection with a simple contact boundary but a close relationship. Some of the porphyrite contains a small amount of silver. .

The sphalerite infiltrate has a particle size of 20 to 60 μm and a maximum particle size of 150 μm. Small galena inclusions can be seen in sphalerite, which is often complicated by galena and complicates the inlay relationship. Chalcopyrite deposits exist in some sphalerites, which affect the separation of copper and zinc minerals to some extent.

The average grain size of galena in the ore is usually 30-60 μm. When forming coarse aggregates with other important sulfides, the particle size is relatively coarse. Galena, which is medium-grained in the crevices of the gangue, is also commonly found. The galena, which is embedded in the sulphide and gangue, is often easily dissociated during the grinding process.

Scanning electron microscopy showed that some galena contained silver, but in more cases, silver minerals were precipitated inside.

The bismuth lead ore is one of the main silver-bearing minerals that obviously contain silver in the ore. The relative content of minerals is about 0.3%, and the silver content generally varies from 0.5% to 4%. It is either in the form of a medium-grained granular filling independently along the ore fissure, or in the form of fine-grained inlays in the gangue, and a part of which is combined with other sulfides. A variety of silver minerals or silver-bearing minerals are also found in other sulfides, especially galena, and most are associated with lead bismuth salts and tellurides. Such silver minerals are closely related to sulfides (mainly galena).

In most cases, pyrite and various sulfide aggregates are embedded in the gangue. Common pyrites are covered with galena in the form of droplets, and the fragmented pyrite is typical of chalcopyrite. The remnant structure of the two types of embedding is not conducive to the dissociation of pyrite from chalcopyrite and galena ^[1-5] .

Third, industrial trials

(1) Industrial test process

The industrial test adopts the copper, lead and zinc full priority flotation process, and the figure 1 is the industrial test principle process flow. The copper selection operation uses one rough selection, three sweeps, and two selection processes. The copper collector is BK901J. The copper tailings are selected for lead flotation, and the lead selection process is one rough selection, three sweeps, and four selection processes. The lead tailings are selected for one roughing, three sweeps and three selected zinc selection processes.

The ore mine adopts a section of grinding, and the fineness of grinding into the flotation is 75%-74μm. Since the ball mill is of the MQGl 500×3000 grid type, it is easy to cause excessive grinding of lead.

(2) Industrial test indicators

After a period of adjustment and improvement, the final process conditions were determined and preliminary test indicators were obtained. From August 25th to September 5th, 2005, a total of 2800t of ore was treated, and the parking was stopped due to water cut or equipment maintenance. The total amount of ore was about 270t/d. The accumulated ore grade was 1.75% copper and lead 5.66. % and zinc 4.64%. The cumulative indicators obtained are: copper concentrate grade 25.53%, copper recovery rate 67.12%, lead concentrate lead grade 65.24%, lead recovery rate 79.42%, zinc concentrate zinc grade 46.43%, zinc recovery rate 82.60%. Among them, individual shifts reached good indicators of copper, lead, zinc grade and recovery rates of 27.85%, 75.58%, 53.29% and 84.18%, 81.42%, and 86.25%, respectively.

Based on the determined process flow and operating conditions, the production indicators for September-December 2005 increased month by month (see Figure 2). In December, the recovery rates of silver in copper concentrates and lead concentrates reached 24.72%. And 60.84%. The indicators indicate that the established process regime is appropriate.

(3) Problems encountered in industrial trials and measures taken

1. Problems encountered in industrial trials

There are many problems encountered in industrial trials, mainly:

1) The ore grade and ore properties fluctuate greatly. The range of raw ore grade fluctuations: copper grade from 1.5% to 2.7%, lead grade from 4% to 7.5%, and zinc from 2% to 7.5%. Due to the large number of ore deposits during mining, the type and type of ore at each point vary greatly, and the irregular surface ore needs to be treated, resulting in a large change in the nature of the ore. Due to site conditions, it is difficult to match ore.

2) There are many secondary slime after the ore grinding, and the mud content of different kinds of ore is different, which makes the operation difficult to stabilize. The thickness of the grinding products is uneven, and the lead is excessively ground, which makes it difficult to further reduce the lead content of the copper concentrate.

3) There are many impurities such as wood residue in the ore, and the circulation hole of the flotation machine impeller is relatively small, which causes the circulation hole on the impeller and the cover of the flotation machine to be blocked frequently.

4) Due to the large variation of raw ore grade, when the ore grade is high, the flotation time is not enough, resulting in poor separation of copper and lead, serious product inclusion, unqualified product quality and low copper recovery rate. The whole work is often not smooth, and the sorting is confusing.

5) Grinding graded overflow concentration is sometimes too large, reaching more than 43%, or even higher, which makes copper-leaf flotation separation difficult.

6) The lime addition system cannot be effectively controlled, resulting in a large change in the amount of lime added, and the pH fluctuation of the slurry is large, which affects the flotation effect.

7) Some drugs appear to be broken or blocked.

2. Measures taken in industrial trials

In response to the above problems, under the organization of the Industrial Test Leading Group, the heads of the mineral processing, mining, equipment and other departments and the mineral processing and other related professional and technical personnel conducted regular discussions and communication, and adopted the following main measures:

1) Stabilize the nature of the ore and strengthen the ore blending.

2) Strictly control the feeding of the ball mill, adjust the proportion of various ball diameters in the ball mill, adjust the operating conditions, and stabilize the grinding fineness of a section as much as possible from 75% to 80% to 74 μm.

3) Strengthen the technical requirements for separation of copper and lead flotation, and stabilize the coarse ore concentration to 35% to 36%. When the ore grade is high, the raw ore treatment volume is appropriately reduced to ensure the flotation index.

4) For the problem of wood residue in the flotation slurry, an isolation device is added to the agitation tank.

5) Make appropriate modifications to the flotation machine.

6) Partial transformation of the zinc rough selection and selection process.

7) Improve the process pharmaceutical system. In view of the characteristics of the original ore and the change of the grade, the dosing point and dosage of the inhibitor are adjusted, thereby stabilizing the effect of copper and lead separation so as not to fluctuate due to changes in the ore. Adjust the way and location of the copper collector. According to the results of laboratory tests, the copper collector dosing point was changed from a stirred tank to a ball mill to increase the recovery rate of copper and reduce its impact on subsequent flotation.

8) Renovate the lime dosing system, accurately control the amount of addition, control the pH of the slurry, and stabilize the production conditions.

Fourth, the conclusion

(1) The use of copper, lead and zinc sequential preferential flotation process to treat Xiaomaoshan silver-copper-lead-zinc ore has achieved long-term stable operation in industrial production. In December 2005, a lead concentrate containing 24.80% copper, 77.0% copper recovery, 61.28% lead and 75.40% lead recovery, and 48.47% zinc and 80.02% zinc recovery were obtained. Zinc concentrate. The total recovery of silver in copper concentrates and lead concentrates is 85.56%.

(2) It is necessary to carry out detailed laboratory research on the ore of different ore bodies to determine the selectivity and pharmacy system of different types of ore to further guide production.

(III) Also participating in this industrial test are the Beijing Research Institute of Mining and Metallurgy and other comrades of the Xiaomaoshan Copper-Lead-Zinc Mine in Suzhou.

references

[1] Wang Yun, Zhang Lijun. Experimental study on mineral processing of complex copper-lead-zinc polymetallic sulfide ore [J]. Non-ferrous metals: mineral processing, 2007, (6): 1-6.

[2] S. Blatovich. Research and application of new copper and lead separation method in Laura concentrator in Peru [J]. Foreign metal ore dressing, 2002, (3): 21-25.

[3] Ni Zhangyuan, Wang Xianxing. Study on the beneficiation process of a refractory polymetallic ore in Xinjiang [J]. Mining and Metallurgical Engineering, 2003, 23 (2): 30-32.

[4] Zhang Xueqiang. Industrial experimental study on optimized blending of sodium sulfide and lead-zinc separation operations [J]. Gansu Metallurgy, 2003, 25: 48-50.

[5] Yin Jiangsheng, He Ruigang, Shen Kaining. Study on copper ore, zinc and iron ore beneficiation process [J]. Nonferrous Metals, Washing Section, 2007, (1): I-5.

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