Technological transformation of molybdenum selection system in Baihualing Concentrator

I. Overview

BAIHUALING beneficiation plant is one of molybdenum concentrator JINDUICHENG Molybdenum Company subsidiary, its scale of production belong to China and Asia's largest molybdenum concentrator.

The plant was completed and put into operation in October 1983. The design scale is 15000t/d. The design index contains 0.100% molybdenum in ore, 45% molybdenum in concentrate, and 85% molybdenum recovery rate. At present the main products are molybdenum concentrate by-product of sulfur concentrate, iron ore and copper concentrates.

In recent years, the plant has carried out a large number of technical innovation work, and has carried out technical research and technological transformation many times, making the main mineral processing technical and economic indicators exceed the original design indicators. For example, after reducing the particle size of the crushed ore, the crushing process is optimized and the management is strengthened. The crushing size is reduced from -20mm to 75% to -15mm, and the ball mill efficiency is 64t/set·h (designed as 70t/set·h). ), increased to 85t / Taiwan h. The production scale of mineral processing has reached 20,000t/d (including the addition of Taiwanese 3.6×6m ball mill to increase the daily processing capacity by 2300t), which is 3396 more than the original design capacity. The process is transformed by the molybdenum rough selection system. The grinding production capacity is adapted, and the crude recovery rate is improved from the stability; through several technical improvements to improve the quality of molybdenum concentrate, the grade of molybdenum concentrate is increased from 45% to 47%, and then increased to 50%. The effect of molybdenum market price, the original ore grade of molybdenum is adjusted from 0.100% to 0.130%.

With the increase in the capacity of the treated ore and the change in the nature of the ore, the original molybdenum selection system of the plant has been unable to meet the production needs. The main problems are:

(1) The original design adopts the "A" type flotation machine, the performance itself is backward, and after years of running wear and tear, the equipment is aging, the performance is further reduced, and the maintenance is frequent. Run, run, drip, and leak occur frequently, which seriously affects normal production.

(2) The flotation volume is too small, and the flotation time is short, which causes the selection operation to be abnormal. The phenomenon of troughing and stringing is serious, resulting in a decrease in the selected recovery rate and difficulty in improving the concentrate grade.

(3) In order to adapt to the ability of the selected section, the rough selection section must reduce the yield of coarse concentrate and increase the grade of coarse concentrate, resulting in a decrease in the recovery rate of rough selection.

With the development of market globalization, users are constantly improving the quality requirements of their products. Of course, the lower the price, the better. The problems in the selection process of the plant directly affect the production and quality of molybdenum concentrate, which in turn affects the competitiveness of molybdenum products in the international market and the economic benefits of the company. Therefore, the technological transformation of the system is imperative.

Second, the research and design of the transformation plan

According to the research of the company expert meeting, the research and design principles of this transformation plan are as follows: (1) The process flow and technical indicators must be advanced and reasonable. (2) The equipment selection is stable and reliable, the level is advanced, and it has the characteristics of high efficiency and low consumption. (3) System processing capacity Based on the current production capacity, there is a certain surplus. (4) The equipment configuration has the flexibility to change the process. Make the overall design in place, but be able to implement it step by step. In the step-by-step implementation process, the production is not affected as much as possible, and the equipment configuration is compact and reasonable, which is convenient for production management and operation. (5) Make full use of existing facilities and minimize the amount of construction to ensure that investment is less effective. (6) There is room for future development of automation control.

Based on a series of in-depth and meticulous investigations and scientific arguments. According to the company's ability to pay funds and the degree of urgent need for production, the company decided to take out more than 5 million yuan of funds, first implement the first step of transformation, the content is: (1) the selection of section flotation machine replacement. The new "BF" self-aspirating flotation machine was used to replace the original "A" flotation machine and adopt a new configuration. (2) Optimizing existing process parameters. For example, the second selection of the rough selection section is removed. Appropriately reduce the coarse quality position, improve the yield of coarse concentrate; strictly and improve the existing re-grinding operation and management system to make full use of the fine grinding effect; reduce the cyclone overflow concentration (ie reduce the concentration of selected operations) ) Guaranteed overflow fineness.

1. Configuration of flotation machine and accessory equipment

This transformation was compared through a variety of configuration options. It is determined that it is still divided into three series, and the original structural process is maintained, that is, one rough and two sweeps. The new for BF type flotation machine (BF4.0m ³ 34 sets, BF1.2m ³ 62 units) mounted adjacent thereto, elevation 8.65m. It is 144m long and 6m wide (this factory spans 15m) in the idle factory space. (This factory was originally installed with 7A (volume 5.8m/set) sulfur flotation machine. In 1993-1996, this flotation machine was replaced by KYF24m ³ and XCF24m ³ external pneumatic mechanical agitation flotation machine. Because of flotation machine The volume is increased, so a lot of plant area is saved).

The advantages of this configuration are three: First, the original 7A flotation machine equipment base can be utilized, which can save investment and shorten the construction period; second, the position of the re-grinding machine and the cyclone equipment elevation does not change, and the new installation equipment can still ensure the slurry self-flow. The process is smooth; the third is to adopt the "-" shape arrangement, neat and beautiful, easy to operate and equipment maintenance, which is conducive to the loss of all metal recycling.

2, transformation design features

According to the actual molybdenum selection process, we dare to change the local equipment structural parameters of the “BF” flotation machine. For example, the size of the ore discharge method and the size and position of the discharge port have been changed. Production practices have proven that this change is scientifically effective and successful. The move also laid the foundation for the success of the new process.

In order to facilitate the future production technology management and process inspection, the tailing box of the flotation machine was decisively improved, and the sampling box between each operation was added.

In order to extend the service life of the equipment, the metal loss is eliminated, the operating expenses of the equipment are reduced, and the phase body of the snorkeling machine is subjected to wear protection treatment at the same time as the equipment is installed. That is, a cast stone with a thickness of 25 mm is laid on the bottom of the grid, and the wear-resistant composite material is lined on the side surface of the flotation machine tank and the inner wall of all the process pipes to ensure that the flotation machine does not leak for at least 15 years.

The scientific optimization of the production process parameters is the most important factor to ensure the success of this transformation.

By adding a Φ150mm pipe, the incoming ore quantities of the three selected systems can be colluded with each other. This ensures that no matter which regrinder or group of flotation machines can be overhauled, the product quality and recovery rate can be stabilized. The normal driving of the upper process makes the entire selection system a flexible process. Effectively improve the overall beneficiation equipment operating rate. Practice has proved that this measure is very effective and effective.

Third, the comparison and analysis of indicators before and after the transformation

(1) Comparison of technical indicators of selected systems before and after the transformation (see Table 1).

Table 1 Comparison of main technical indicators at each stage of the selected system

Note: The results of the rough tail examination in March and August 1997 were 0.526%, which was similar to the 0.521% of the results from April to June 1998. It can be further explained that the selected recovery rate before transformation is only about 95%.

It can be seen from Table 1 that the selected indicators are significantly improved after the transformation. Compared with before the transformation, the grade of molybdenum concentrate increased from 50.75% to 52.45%, up 1.70%, and the selected recovery rate increased from 95.29% to 97.64%, an increase of 2.35 percentage points. The finished tail grade was reduced by 0.273 percentage points, and the rough selection recovery rate was increased by 0.45 percentage points. Thus, it can be stated that the first step of the transformation is successful. It has reached and exceeded the molybdenum concentrate grade by 51.5%, and the selected recovery rate has increased by 1%.

(II) Comparison of the quality structure of molybdenum concentrates before and after the renovation (see Table 2).

Table 2 Statistics on product structure changes before and after molybdenum selection process

Before the transformation, the selection operation was very abnormal, and the phenomenon of running the trough and the trough was very serious, which led to the inevitable loss of the selected recovery rate of the molybdenum concentrate grade to meet the market requirements. After the transformation, the flotation machine has superior performance and reasonable process, which not only improves the grade of molybdenum concentrate, but also improves the selected recovery rate. In particular, the content of major impurities in molybdenum concentrates decreased, and the maximum decrease of SiO ₂ impurities was 1.86 percentage points (see 1), which caused a fundamental change in the quality structure of molybdenum concentrate products sold (see table). 2), the special grade rate reached 29.47%; the quality product rate increased by 30.44 percentage points, the first grade rate and the second grade rate decreased by 15.49 and 43.42 percentage points respectively, which greatly enhanced the competition of molybdenum products in the international market. The ability to fully prove that the first transformation is successful.

(III) Analysis of the results

The reason why this process transformation can achieve such an ideal result is that in addition to the efficient and low-cost "BF" flotation machine, another main reason is to optimize the main process parameters (see Table 3).

Table 3 Statistics on process parameters change of molybdenum selection system

The "BF" flotation machine impeller consists of a closed double-section cone, which can produce a strong slurry down cycle. The suction volume is 0.3-0.4m3/m ² ·min larger than the "A" type flotation machine, and the stirring force is strong. The slurry gas is evenly mixed, and the degree of bubble mineralization is high. Especially after the position of the control gate (discharge port) is moved down, the mineralized foam layer is thickened. The upper layer bubbles are continuously merged, resulting in a strong "secondary enrichment" effect, causing the impurities entrained in the machine to be scattered, returning to the slurry, and effectively separating the useful minerals and impurities, so that the grade of the molybdenum concentrate is increased and the impurities are lowered.

After the transformation, the total volume of the flotation machine of the selected system has more than doubled before the transformation (see Table 3), and the flotation time is greatly extended, even if the processing capacity of the ore is increased, or the grade of the ore is increased and the process occurs. In the case of large fluctuations, the selected slurry can be fully and effectively selected to ensure the recovery rate of selected operations. In addition, the expansion of the flotation volume will create conditions for optimizing the rough selection process of molybdenum, that is, removing the second coarse selection, increasing the yield of coarse concentrate, and appropriately reducing the grade of coarse concentrate. At the same time, it is also very beneficial to improve the recovery rate of rough selection. The expansion of the flotation volume, when the original ore grade is low, stops a selected system for maintenance, and opens two selected systems without affecting the operation of the upper process equipment, creating conditions. It ensures the overall operation rate of the entire beneficiation equipment.

It can be seen from the data in Table 3 that after the transformation, the process parameters of the new process are optimized by strengthening management and changing the original operation method. Firstly, the concentration of the re-grinding cyclone is reduced by 3.32 percentage points, which effectively reduces the concentration of the selected process. In addition, the selection of various operations increased the amount of foam washing water, so that the flotation concentration of selected operations was generally reduced by 3-4%. The swirler-flow rate of 0.0385mm is increased by 17.60% compared with the previous one, which effectively improves the monomer dissociation degree of useful minerals in the selected materials. Both theoretically and practically, it is fully proved that the reduction of the concentration of selected operations and the improvement of the dissociation of useful mineral monomers can effectively separate the useful minerals from the impurity minerals, ensuring the improvement of the molybdenum concentrate grade and the recovery rate. Prerequisites are provided. Secondly, the increase of the amount of collector kerosene makes the process conditions more reasonable, and the operation of the whole flotation process is more stable, which is also conducive to the improvement of the selection index.

Fourth, the benefit analysis

(1) Quality benefits

Quality is the life of an enterprise and determines the survival of the company. This platinum selection system process transformation. The average grade of molybdenum concentrate was increased from 50.75% to 52.45%, an increase of 1.70 percentage points. In particular, the structure of molybdenum concentrate products has undergone major changes, and the rate of special grade products (Mo ≥ 53%) has reached 29.47%, which further strengthens and strengthens the quality advantage of “JDC” molybdenum products and continues to maintain its leading position in China. And enter the international advanced ranks, effectively improve the competitiveness of the molybdenum products in the market and the vitality of the enterprise, and have significant social benefits. In addition, the company can obtain more than 30 million yuan of direct sales per year for the sales of premium products. benefit.

(2) Recovery rate benefit

According to statistics, the selected recovery rate after the transformation is increased by 2.35 percentage points, and the gross recovery rate is calculated by 0.2 percentage points. The total recovery rate can be increased by 2.26 percentage points. According to the current actual production capacity of the plant, more molybdenum concentrate can be produced. Hundreds of tons, an increase in output value of more than 10 million yuan.

V. Conclusion

(1) The main factors affecting the grade of molybdenum concentrate and the recovery rate of beneficiation in Baihualing Concentrator: First, the selected equipment has small volume and backward performance; secondly, the process is imperfect.

(II) Reconstruction plan For the characteristics of molybdenum selection, the structural parameters such as the height and width of the mine ram of the BF-1.2 flotation machine were creatively improved, and the effect was very significant, which was used to improve the technology of the selected system. To a critical role.

(3) Strengthening the existing one-stage re-grinding operation management, strict process discipline and optimizing process parameters are another key factor for improving selected indicators.

(4) More than two years of production practice has proved that the selected "BF" flotation machine has good performance, reliable operation, stable ore surface, easy operation and high efficiency. It is an ideal new flotation equipment . Successfully applied for the first time in molybdenum selection.

(5) Compared with before the transformation, the “BF” flotation machine can achieve 52.45% of the grade of molybdenum concentrate in the case of similar ore grades, and the selected recovery rate reaches 97.64%, which is 1.70 and 2.35 respectively higher than that before the transformation. Percentage, while the unit volume power consumption is 10.84% ​​lower than the "A" type flotation machine.

(6) The first step of equipment transformation and process optimization completely solved the problem of insufficient capacity of the selected system and poor process, and the technical and economic effects were very significant. The annual net income of the enterprise is 11.25 million yuan, which can directly delay the second-step technological transformation and save investment of several million yuan, which provides a reference for the selection of similar mining equipment and equipment renewal.

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