Energy saving and consumption reduction has now become a very important task in the sustainable development of mineral process plants, it should actively take a variety of effective measures to continuously improve production efficiency, reduce energy consumption, and thus improve the economic and ecological benefits of mineral process plants.
The following 22 tips are common methods for energy saving and consumption reduction in a mineral process plant.
1. More crushing but less grinding, choose the reasonable feeding size for grinding
Production practice shows that about 60% of the energy consumption in the beneficiation process is consumed in the ore crushing and grinding operations, so energy saving in mineral processing plant should first be in the crushing and grinding stage.
For the mineral processing plant in production, the crushing and grinding equipment has been basically fixed, now can only balance the crushing and grinding capacity, which requires that on the basis of ensuring the crushing capacity, the discharge size of the crusher is reasonably adjusted to produce smaller sizes products, which will further reduce the pressure of the grinding section and increasing the grinding efficiency.
2. Add pre-selection process to remove the gangue in advance
Before the ore crushing or grinding, there are ways to enrich the ore in advance, like hand sorting, color separation, electric separation, magnetic separation, etc. After pre-selection, it improves the raw ore grade, reduces the amount of ore for crushing and grinding, thus significantly improving the grinding efficiency and reducing energy consumption.
3. Automatic control of crushing production
Adopting automatic control system, it can realize the sequence control, logic chain control, fault protection control of crushing process equipment, automatic control of crusher feeding, automatic control of ore bin distribution, etc., which can reduce workers’ labor intensity, reduce equipment failure rate and improve equipment production efficiency.
4. Use high pressure grinding rolls
The high pressure grinding rolls is composed of a pair of pressure rollers rotating synchronously in opposite directions, one is fixed roller and the other is a dynamic roller. It has obvious energy-saving advantages compared with other crushing equipment. The material enters through the feed opening above the pressure rollers, it is carried between the rolls by the rotation of the pressure rollers, and is strongly squeezed to form a puffy material cake and discharged from bottom.
High pressure grinding rolls crushing process is the implementation of quasi-static pressure crushing, comparing with high speed rotation method this quasi-static pressure crushing saves energy consumption of about 30%. Compared with other crushing methods, the energy loss of compressive stress layer crushing is small and the utilization rate is high, and the discharged material cake not only contains a large proportion of fine particles, but also produces a large number of cracks inside the particles, thus improving the grindability of the material for subsequent grinding, increasing the production capacity of the grinding system, and significantly reducing the grinding power consumption and steel consumption.
5. Choose high-efficiency large grinding equipment
Large ball mills generally use hydraulic power and advanced equipment such as hydrostatic bearings and oil injection devices, effectively improving the economic efficiency of mill operation, while its unit energy consumption is significantly lower. Large ball mills not only reduce energy consumption, but also enhance the stability of the process and improve production efficiency.
6. Ensure the stability of mineral density during grinding
The level of mineral density is related to the nature of the material to be ground. The mineral density should be higher for materials with large feed size, high ore hardness and high density. On the contrary, the mineral density should be reduced appropriately. Generally, the mineral density of first stage is 75% to 82%, and the second stage is 65% to 72%.
In the process of grinding, it should be fully ensured that its feed volume is stable, and based on this, adjust the water volume of the first stage grinding, and pay attention to the classification operation to obtain a relatively ideal density. The second stage grinding mainly depends on the fineness of the first stage grinding product, therefore, in order to better control the second stage grinding density, effective measures can be taken to strictly control the fineness of the first stage grinding product, while in the return operation according to the actual needs to set slurry concentration equipment, and continuously improve the efficiency of grinding.
7. Choose the right type of liners
Rubber liner and magnetic liner technology should be tried in the process of grinding. Rubber liner is more flexible and corrosion resistant, and its energy consumption can be reduced by about 10% compared with the traditional technology. The magnetic liner has better durability, smaller thickness, lighter mass, and less energy consumption, the application of magnetic liner can significantly reduce energy consumption.
8. Develop a reasonable system for adding steel balls
Steel balls have a greater impact on the productivity of the ball mill, the selection of ball diameter is directly related to the efficiency of grinding, and the size of the selected medium should be decided according to the nature and size of the material. The reasonable system includes the amount of balls added, the size of ball diameter and the interval time of adding balls, which is related to the particle size, hardness and slurry density of grinding materials. It is necessary to add the grinding media moderately with the actual situation, and strictly control the shape, volume, adding amount and time interval.
9. Reasonable use of grinding aids
The use of appropriate grinding aids can improve grinding capacity and reduce energy consumption. Where the fine grinding process can significantly improve the efficiency of the crushing or reduce energy consumption of chemical substances, it is called grinding aids. By adding grinding aid to improve grinding efficiency has long been successfully applied to grinding production, efficient ore grinding aid will have a significant effect on energy saving and consumption reduction.
10. Improve classification efficiency
In order to ensure the scientific and reasonable grading size, many mineral process plants are currently applying the grinding and grading closed circuit system in the production. Over-grinding and classification efficiency have a very close relationship.
At this stage, a large number of new equipment gradually appear in the production chain, which also ensures the effect of enhanced classification. Furthermore, coarse particle classification can also be done by means of fine sieving to reduce the energy consumption generated by the operation of the spiral classifier. In fine particle classification, efficient separation equipment such as hydrocyclone or high-frequency fine screen can be used. Under the effect of enhanced classification operation, the system can separate qualified particle grades in time to avoid over-grinding problems and effectively reduce the energy consumption in the grinding process.
11. Grinding and classification automation control
Actively take effective measures to implement automatic control. The ball mill automatic control system can detect the audio, power and classification current of the mill by itself, analyze and study the operation status of the mill comprehensively, and then realize automatic control in terms of ore feed, concentration and classification overflow size, continuously improve the efficiency of grinding and classification, and show the role of the grinding and classifying machine to the greatest extent.
Investigation shows that after the automatic control of grinding and classifying circuit, the output of the mill and the recovery of beneficiation metal are significantly increased, the energy consumption is reduced by 10%, and the process stability in the grinding process is stronger, so the advantages are very obvious.
12. Select high-efficiency sorting equipment
The use of new high-efficiency sorting equipment is one of the keys to achieve energy saving and consumption reduction in sorting. At present, there are many different kinds of flotation equipment with different quality, the selection of equipment should be compared based on different mining site circumstances. For example, compared with small flotation machine, large flotation machine with low energy consumption, small area for installation and higher degree of automation; flotation column compared with flotation machine, in the case of obtaining the same grade, it can simplify the number of selections, decrease the amount of pharmaceuticals and reduce energy consumption.
13. Select the efficient mineral processing chemicals
Mineral processing chemicals have an extremely important role in a mineral process plant. High-efficiency mineral processing chemicals can save 1/3~1/2 of the dosage, significantly reduce the cost of chemicals and greatly reduce the cost of mineral processing, meanwhile it improves the grade of the concentrate and increases the recovery rate.
14. Increase the tailing discharge density reasonably
Tailing with high density slurry for conveying by pipeline is the most economical way. Reasonable choice of slurry concentration can reduce the operation power of tailing thickener and slurry pump, it also can reduce the diameter of tailing transfer pipelines and return pipelines as well as their accessories, thus can reduce the design scale of the tailing pumping station.
15. Mineral processing water in closed-circuit recycling
The closed circuit recycling of mineral processing water is another important aspect of the mineral processing plants to promote energy conservation and consumption reduction. Beneficiation plant uses a lot water and accounts for a large proportion in the total investment, save water and reuse of water have obvious effects on the energy saving of the total plant.
In the gravity and magnetic separation process, the impact of water on the beneficiation index is not significant, the water for shaking table and high pressure pumps do not use too much water, these equipment can use fresh water, while other equipment can use recycled water. The flotation process has certain requirements for the recycled water, because residual chemicals in will have a negative impact on some operations, in this case the recycled water can only be used for some operations.
16. Adopt frequency conversion control technology
Frequency conversion control has been commonly used in many mines as an effective way to save energy. Frequency converters can realize soft starting of motors, achieve the purpose of energy saving and speed regulation by changing the input voltage frequency of equipment, and can provide protection functions for equipment such as over-current, over-voltage and overload. Frequency conversion control can be used on the belt conveyors, ball mills, slurry pumps and other heavy loads, which can not only reasonably adjust the process parameters, but also significantly reduce energy consumption.
17. Appropriate use of new materials to improve the service life of equipment
In some easy wearing parts like the jaw plates, ball mill liners, can use new wear-resistant materials, in the magnetic separation drum using adhesive wear-resistant ceramic plates, in the slurry pump and flotation machine impeller coated with wear-resistant polymer particle rubber, tailing pipeline using polymer polyethylene wear-resistant pipe, spiral classifier screw plates using ceramic materials, belt conveyors using wear-resistant corrosion-resistant waterproof rollers, the application of these new materials, not only to reduce the cost of mineral processing, but also to extend the service life of the equipment, it also reduces maintenance.
18. Use the electricity wisely
As the electricity price during peak period is much higher than the price of valley period, try to reduce equipment operation during peak period, although the total amount of electricity is not reduced, but can significantly save electricity costs, thus reduce production costs.
Most of the mineral processing plants are continuous production, but some stages can be regulated. Like crushing process, it makes full use of the transfer hopper, avoid peak period operation, equipment maintenance and repair can be done during this time, during the valley period can increase the production of crushing stage in a maximum way.
19. Achieve automation of mineral processing plant
At current stage, automatic control technology, automatic detection instrumentation and information processing technology are widely used in the production of mineral processing plants. In the mineral process plant, automatic control technology mainly consists of three parts, which are production process control system, production execution system and multimedia monitoring system. The three parts are cooperated with each other to effectively realize online production scheduling and production management, to ensure the quality and efficiency of the beneficiation work, so as to optimize the technical and economic indexes of the beneficiation process, and truly realize the purpose of efficiency, consumption reduction and energy saving.
20. Comprehensive utilization of the ores
In order to make maximum use of each component in the ore, each useful mineral should be processed to maximize the recovery.
21. Continuous optimization of the beneficiation process
Technology, equipment and reasonable process diagram have a very significant impact on the quality and efficiency of production, advanced energy-saving technology and energy-saving equipment to improve the quality of mineral processing, and simplify the process of mineral processing. The scientific application of energy-saving technology and equipment in the mineral processing plant will be able to maximize the positive effects of a variety of processes, technology and equipment, on the one hand, it simplifies the process, on the other hand, it also reduces the energy consumption.
22. Strengthen training and management of energy saving and consumption reduction
In response to the problem of people’s poor awareness of energy saving and consumption reduction, mineral enterprises must strengthen the publicity work of energy saving and consumption reduction, and raise people’s awareness of energy saving and consumption reduction.
First of all, for the internal enterprise, managers should organize energy-saving technical training for manage level and front-line operators to continuously improve and enhance energy-saving techniques, methods and means to promote energy-saving and consumption reduction. At the same time, the training of personnel within the enterprise should be strengthened to continuously improve the staff’s responsibility and awareness of responsibility, and raise their awareness of energy saving and consumption reduction, thus facilitating and guaranteeing the development of energy saving and consumption reduction management.
Secondly, clarifies the operation process of machinery and equipment in the beneficiation process, so that operators can operate the machinery in a reasonable and scientific way. Thus it guarantees the beneficiation efficiency, as well as reduces the energy consumption of equipment, thus increase the economic benefits of mineral enterprises.
In short, energy saving and consumption reduction is a long-term and arduous task for mineral process enterprises, the mine owner should dig deep of the potentials, and constantly develop and apply energy-saving diagram, new technology and equipment.