First, energy saving measures

(1) Energy-saving measures for the crushing production process

Beneficiation plant process consumes a lot of water, electricity and other energy. The main energy consumption in the production process of the ore dressing occurs during the crushing and grinding process. According to research data, in the production process of the concentrator, the electricity used in the crushing process accounts for about 10% of the total electricity consumption, and the electricity used in the grinding process accounts for about 50% of the total electricity consumption. 60% of the electricity.

More crushing and less grinding is the most effective measure for energy saving in the concentrator. By adopting advanced fine crushing equipment, the particle size of the crushed product is reduced, the grinding grain size of the grinding process is reduced, the crushing efficiency is improved, and the workload of the grinding process is reduced, thereby effectively Reduce the electricity consumption of the concentrator.

The crushed product is screened by an advanced graded inspection sieve, and the broken crushed screen is replaced in time to improve the screening efficiency after crushing. Reducing the particle size of the crushed product, a ball mill to reduce the particle size into the mill to improve the grinding efficiency of the mill.

Jinduicheng Molybdenum Company BAIHUALING processing plant in 1991 by improving the crushing ratio and reasonable process of crushing and screening equipment, so that the broken product particle size increased from 75% to -20 mm -15mm accounted for 90.2%, grinding The efficiency increased from 64.16t/h·h in 1991 to 78.77t/t·h in 1995, and the energy consumption of grinding decreased by 1.016kwh/t ore ^[1] .

(2) Energy-saving measures for the grinding production process

The classification effect of the grinding products directly affects the energy consumption of the ball mill. The high-efficiency grading equipment is used to improve the classification efficiency of the grinding products, reduce the return amount of the grinding process, and reduce the cyclic load. Such as cyclone and other alternative spiral classifiers, such as low efficiency and poor classification efficiency, can reduce the amount of minerals returned to the ball mill, increase the amount of new ore processed by the ball mill, improve the efficiency of the ball mill, and reduce the energy consumption of the grinding process.

The liner of the ball mill is a consumable item. Conventional manganese steel backing large mass consumption not easy to wear and convenient maintenance and replacement, while the consumption of large ball. The use of a gel liner and a magnetic liner can reduce the weight of the ball mill itself, reduce energy consumption, and increase the throughput of the ball mill. And the rubber liner and the magnetic liner itself are more wear-resistant than the traditional manganese steel liner, the ball consumption is small, and the replacement and maintenance are more convenient. The use of colloidal lining and magnetic lining can effectively reduce the production cost of the plant. At the same time, the wear resistance of the rubber lining and the magnetic lining enables the concentrator to produce stably for a long time, reducing the number of stops and driving, and making the product quality. Can be guaranteed.

The steel balls (rods) in the ball mill are also a major consumption in the production process of the concentrator. During the grinding process, a certain amount of steel balls are consumed as production progresses. In the production process, a certain amount of new steel balls (rods) need to be added to the ball mill to ensure that the grinding process can continue, and the particle size of the grinding products can be stabilized. The use of wear-resistant high-strength, wear-resistant bearing steel balls (rods) can reduce ball consumption and reduce production costs. There are also factories that use high-strength ceramic balls to replace traditional steel balls. The use of ceramic balls not only reduces ball consumption, but also reduces the incorporation of metallic impurities such as iron during grinding. For some products that require product quality, the quality of the product can be improved.

Changing the shape of the grinding medium can improve the grinding efficiency and reduce the energy consumption to a certain extent. In the rough grinding process, a rod mill or a steel ball with a larger particle size is used to improve the impact force. The fine grinding process uses a steel ball with a smaller particle size to increase the grinding force. The steel balls in the ball mill can also improve the grinding efficiency and reduce the energy consumption by using the appropriate ratio of the large and small balls.

For some ores, self-grinding, semi-self-grinding grinding processes can be used. The self-grinding and semi-self-grinding process simplifies the process and improves operating conditions. The self-grinding and semi-self-grinding process can reduce the ball consumption of the ball mill, reduce the weight of the ball mill itself, and reduce the power consumption.

The use of advanced bearings is an important way to save energy and reduce consumption of ball mills. At present, the rotary spindle of most ball mills in China still uses plain bearings of babbitt. This type of bearing not only has high frictional power consumption, but also has a short service life. The hydrostatic bearing realizes complete liquid lubrication. There is always a layer of pressure film between the two friction pairs, which has the advantages of large bearing capacity, high motion precision, good seismic performance, long service life and low frictional power consumption. Therefore, the application of static pressure support technology to the ball mill using the traditional Babbitt sliding bearing will have significant energy saving effect, and at the same time, the use of the main shaft and the bearing bush can be extended.

(3) Using pre-selection methods to achieve energy saving and consumption reduction

For some mines, it is possible to take a pre-selected process of underground coarse crushing to discharge gangue minerals in advance. Especially in the case of depletion of resources, small and thin ore bodies, and high mining depletion rates. Data show that in the mining process, the waste rock mixing rate in the ore is as high as 20% or even 50% ^[2] . Therefore, coarse pre-selection of raw ore in the underground can greatly reduce the processing capacity of the ore processing plant. Thereby reducing the amount of material that needs to be processed by crushing and grinding, and effectively reducing the energy consumption, machine wear and ball consumption of crushing and grinding, especially grinding.

For some minerals with magnetic and electrical properties, dry pre-selection can be used for tail-concentration. For ore with high depletion rate, the ore is pre-enriched and pre-thrown by means of electric separation, photoelectric sorting, heavy medium sorting, magnetic separation and the like after coarse crushing. This can reduce the amount of ore crushed and the amount of grinding while increasing the quality of the selected grade, thereby reducing energy consumption.

(4) Large-scale flotation equipment

At present, the flotation equipment widely used in China has three kinds of self-suction, aeration mechanical agitation and aeration. The research and progress of the flotation machine mainly focus on the flotation machine tank structure, impeller shape, impeller speed, impeller diameter, Stator and other aspects. Commonly used flotation machines include BSK series flotation machines, SF series flotation machines, JJF series flotation machines, XCF series flotation machines, etc. As the size of the concentrator increases, large flotation machines are widely used. Compared with small flotation machines, large flotation machines have the characteristics of low energy consumption, small floor space and high automation. Australia CadiaRideway gold copper ore were applied Outokumpu's 160m ^3. The Los pelambresi copper mine in Chile uses a Wemco flotation machine with a single tank volume of 130m ³ and 250m ³ as a section of flotation equipment; the development and application of domestic flotation machines is also accelerating. In 1990, Dexing Copper Mine Dashan Dressing The factory successfully used the largest CNNC-39 m ³ flotation machine in China, and the KYF series flotation machine independently developed by Beijing Research Institute of Mining and Metallurgy, the single tank volume increased from 50m ^{3 in} 1997 to 160m ³ in 2005. The company completed industrial testing. At present, the Beijing Research Institute of Mining and Metallurgy has independently developed a 200m ³ super large inflatable mechanical agitation flotation machine that has passed the appraisal ^[3] .

In January 1998, Jinduicheng Molybdenum Co., Ltd. transformed the flotation equipment and decided to use the new BF self-priming flotation machine instead of the original A-type flotation machine, and adopted a new configuration for the flotation machine. Compared with before the transformation, the BF flotation machine has a similar grade of raw ore, the molybdenum concentrate grade can reach 52.45%, and the selected recovery rate reaches 97.64%, which is 1.70 and 2.35 percentage points higher than the transformation before, respectively. Volumetric power consumption is reduced by 0.84% ​​compared to the A-type flotation machine ^[1] .

In 1993, Jinduicheng Baihualing Concentrator began to replace KJF/XCF-24m ³ and 8 m ³ with XJK mechanical agitating flotation machine selected for molybdenum sulphide rough selection, molybdenum rough selection and sulfur selection. Large flotation machine, and the first slot of each group of flotation machine is changed to XCF type, with self-priming capability. The horizontal configuration of this type of flotation machine is realized for the first time in China. After the flotation equipment is enlarged, the selection index Stable, saving 39%, saving oil by 28% to 46%, saving 60% of the floor space, and obvious technical and economic effects ^[1] .

Therefore, using a large flotation machine can save 50% of the floor space compared to a small flotation unit. The drug consumption is reduced by 10% to 15%. Energy consumption is reduced by 2/3 and the number of motors is reduced by 90% ^[4] .

The flotation column is a new type of molybdenum mine energy-saving equipment. With the maturity of the design, installation, operation and control systems of the flotation column, it is energy-saving and consumption-reducing, processing fine-grade minerals and improving concentrate grade. The superiority is fully demonstrated. The flotation column can simplify the number of selections, reduce the dosage of chemicals, and reduce energy consumption when the same grade concentrate is obtained. The installation power of the flotation column is 88% of the flotation machine. Because there are no moving parts, the production cost is saved. The structure and construction are simple. When the production capacity is the same, the flotation column covers only 65% ​​of the flotation machine, and the civil construction cost is reduced. 15%, the cost is 55% of the flotation machine ^[5] .

(5) Adopting automatic control equipment

The sustainable development of mining enterprises requires the use of limited resources for fine processing, which requires the use of more advanced automation control technology and more advanced management ideas. With a global vision, using leading technology, the company's production process, process, soft and hard environment and other specific circumstances, the use of the overall process control of the overall program to strengthen the control of the total cost.

The frequency conversion speed regulation technology is the most commonly used adjustment control method in the automatic control system, which can not only achieve accurate and quantitative control, but also save energy and reduce consumption. Most of the motors used in China's plant selection are cage motors, which have large total installed capacity and large power consumption. Some of the power is due to the low efficiency of the equipment, and the improper adjustment of the flow method is consumed in vain, and the proper benefits are not exerted. For the energy-intensive links, especially for the mining equipment and slurry conveying equipment, the use of variable frequency speed regulation can significantly reduce the power consumption.

For the crushing process, the automatic control can realize the sequential control of the crushing process equipment, the logic interlock control, the fault protection control, the automatic control of the crusher feeding, the automatic control of the mine warehouse fabric, etc., reducing the labor intensity of workers and reducing equipment failure. Rate, improve equipment production efficiency.

For the grinding process, the automatic monitoring instrument is used to detect the mill audio, the mill power and the classifier current, and the working state of the mill is analyzed. The fuzzy algorithm and fuzzy reasoning are used to optimize the grinding classification control model to realize the automatic control of the ball mill feeding. Automatic control of grinding concentration and automatic control of graded overflow granularity, giving full play to the efficiency of grinding classification and maximizing the processing capacity of the mill. The automatic control system can optimize the grinding and grading production process, fully utilize the equipment efficiency, reduce or eliminate the ball mill's rising belly and idle time, reduce the loss of steel balls and linings, reduce production costs, and have significant economic benefits.

The tailings transport from the concentrator is also a major energy component. The automatic control system realizes high-concentration conveying or constant-concentration conveying through the variable frequency speed regulating tailings slurry conveying pump, which can save energy consumption by 30% to 50% compared with the traditional slurry conveying mode, and improve the utilization rate of circulating water ^[5]. .

Second, reduce emissions

Mining companies, as the number one source of energy (water, electricity, oil, coal, etc.) consumption and solid waste emissions, play a vital role in achieving energy conservation and emission reduction targets. Mining enterprises reduce the production of waste rock, beneficiation tailings and blasting, strong acid concentrated alkali waste gas and tail water waste liquid, improve the utilization of resources, extend the life of enterprises, optimize the operation environment of mining areas, and improve The quality of life in the mining area has improved the relationship between workers and peasants and created a good internal living environment and external social environment for enterprise development. Therefore, energy conservation and emission reduction of mining enterprises is not only a requirement of the state's macro-control policies and social progress, but also an inherent requirement for the survival and development of enterprises. The emission reduction work of mining enterprises is mainly carried out from the following aspects.

(1) Treatment and comprehensive utilization of tailings

The concentrator produces a large amount of tailings during the production process. If these tailings are only piled up in the tailings dam, a lot of farmland and construction materials need to be wasted. The tailings produced by the ore dressing can be used as filling materials to fill the goaf after dewatering by pressure filtration. It can not only solve the problem of source of filling, but also save the cost of building tailings dam, save land and reduce mine tailings. The cost of treatment, improve the mine environment, prevent the surface tailings reservoir from damaging the wild ecological environment due to dust overflow and water infiltration, and eliminate the safety hazards such as mudslides caused by collapse of tailings ponds, which is of great significance for mines to select energy conservation and emission reduction.

Tailings and waste rock can be selected. China's mineral resources are symbiotic, and there are many associated mineral deposits. Some symbiotic or associated minerals and valuable elements enter the tailings respectively, which not only wastes resources but also increases the discharge of tailings. It is important to select the tailings.

Tailings and waste rock can be used as raw materials for building materials. Waste rock can be used as a paving stone. Some waste stones can use the ingredients to make agricultural fertilizer. Due to its fine particle size and high mud content, tailings have a certain viscosity and can be used to produce ceramics, hollow bricks, flat glass and the like.

(2) Tailings water recycling

A large amount of water is needed in the production of the ore dressing plant, and about 4 to 5 tons of water is required for flotation treatment of 1 ton of ore. If new water is used in production, the production cost is high and water is wasted. Therefore, the water in the tailings should be purified and recycled. There are three methods for purifying water in commonly used tailings: (1) natural sedimentation; (2) physical and chemical purification; and (3) chemical purification.

The water in the tailings is returned to the sorting process by the clean water pump after the sedimentation treatment. Not only saves water resources, but also the residual pesticides in the water return to the sorting operation, which can improve the sorting effect and reduce the amount of medicine used.

Third, the conclusion

Mining enterprises are high-energy, high-pollution enterprises. Doing a good job in energy saving and emission reduction can greatly reduce the production cost of the enterprise and maximize the benefits of the enterprise. The significance of energy saving and emission reduction work is not only to reduce the production cost of enterprises, but also to improve the efficiency of enterprises. Its far-reaching significance lies in the comprehensive utilization of resources and the protection of the ecological environment.

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