#cement mill

In modern cement production, the smooth operation of air slide conveyor is crucial. Recently, a cement plant encountered several blockage incidents during trial operations. These issues severely impacted normal production. This article explores the causes of these blockages and the solutions implemented.

1.What is an air slide conveyor?

An air slide conveyor is a bulk material handling system that uses a layer of air to transport dry, powdery materials along a sloped channel. It features a porous surface that allows air to flow through, creating a fluidized bed that enables smooth and gentle movement of materials. This system is energy-efficient and commonly used in industries like cement and food processing.

2.Material Impact

The moisture content of the raw materials significantly contributes to blockages. For instance, clay can have a moisture content of 8% to 10%. The cement plant uses a single-chamber air-swept drying mill. When airflow is too strong, the moisture content of the milled material can exceed 1%. High-temperature, sticky materials can clog the pores of the aeration layer, leading to uneven airflow and causing blockages in the air slide conveyor. Additionally, during shutdowns, materials left in the conveyor can cool and condense, worsening the blockage. To address these issues, the plant implemented the following measures:

Strictly Control Material Moisture: The moisture content of incoming clay is kept below 6%. The gas temperature from the mill is controlled between 90 and 100°C, ensuring the moisture content of the milled material does not exceed 0.8%.

Emergency Cleaning Measures: In the event of unexpected long shutdowns, operators must open the conveyor cover and manually clear the material.

3.Mill Impact

During the initial trial of the cement mill, the spacing of the discharge grate was too wide, and issues with the rotary screen allowed iron scraps, small steel balls, and coarse materials to mix into the milled cement. These materials entered the air slide conveyor via the bucket elevator and accumulated in the aeration layer. When enough material builds up, the injected air cannot fluidize it properly, leading to blockages. To combat this, the workshop took the following actions:

Adjust the Mill Discharge Grate Spacing: This ensures smooth discharge and prevents coarse materials and impurities from entering the conveyor.

Set Up Monitoring Points: Monitoring devices were installed at the bucket elevator outlet and the conveyor entrance. Regular checks help clear any accumulated iron scraps and coarse materials.

4. Conveyor Impact

(1) Sealing Issues

The lower conveyor body was not sealed properly, causing air leaks. This reduced the pressure difference across the aeration layer, preventing proper fluidization of materials and making transport difficult. Upon discovery, the following actions were taken:

Enhance Sealing: Additional clamps or sealing tape were used to address air leakage.

(2) Aeration Layer Damage

Damage to the aeration layer can cause air to short-circuit, leading to air jets that obstruct the material flow. As a result, blockages occur. To resolve this, the plant took immediate action:

Regularly Inspect the Aeration Layer: Any damage should be addressed promptly with repairs or replacements.

(3) Exhaust Design Problems

The upper conveyor should maintain a zero or slight negative pressure. However, the plant's design connected the conveyor's exhaust to the bucket elevator housing, which was not linked to the dust collection system. This caused inadequate exhaust and positive pressure in the upper conveyor, making it difficult for materials to fluidize. To fix this issue, the plant implemented the following solutions:

Redesign Exhaust Outlets: The conveyor's exhaust was connected to relevant equipment to ensure smooth airflow.

Control Air Inflow: The opening of air valves was adjusted based on material characteristics to ensure even airflow and reduce blockage risks.

(4) Weather Impact

The plant's outdoor air slide conveyors were exposed to rainwater, which seeped through gaps and caused material to become sticky, leading to blockages. To mitigate this, the plant took the following steps:

Install Rain Protection: The outdoor conveyors were modified with protective measures to prevent rain from entering and affecting material properties.

In conclusion, through thorough analysis and effective solutions for air slide conveyor blockages, the cement plant has improved its operating procedures and established preventive measures. After over a year and a half of production, the operation of the air slide conveyors has stabilized, ensuring smooth cement production.

A partner company owns a Φ4.2m×13m ball mill. Its cement grinding system consists of a CLF180-120 roller press (capacity of 850 t/h, 1400kW×2), a V-type classifier (V8820 static airflow classifier), a high-efficiency classifier, and a Φ4.2m×13m open circuit tube mill (main motor power of 3,550 kW). This setup forms a combined grinding system.

This system mainly produces P·O42.5 cement, achieving a specific surface area of ≥330 m²/kg, with a system output of 200 t/h and a grinding power consumption of 29 kWh/t. However, the mill's hourly output is low, and energy consumption is relatively high. To increase the mill's output and reduce energy consumption, Darko optimized the efficiency of the roller press and V-type classifier during the off-season in December 2022. They improved internal ventilation and controlled the flow rate, raising the mill's output to 230 t/h and reducing power consumption to 24 kWh/t.

01 Measures for Increasing Production and Reducing Consumption of the Roller Press System

Based on actual conditions, the optimal mill output occurs when 80μm sieve residue of the input material is below 50%.

1.1 Timely Replacement of Damaged Side Plates on the Roller Press

Before the upgrades, the current of the roller press's circulating elevator often ran high. Analysis showed two main reasons:

The wear gap of the roller press side plates was too large, leading to material leakage.

The original gap of the side plates was excessive, causing material leakage.

Long-term leakage not only reduced the efficiency of the roller press but also caused the elevator's current to run high for extended periods, significantly shortening the lifespan of the reducer. Therefore, the following measures were implemented:

Adjust the original gap of the side plates to 2-5mm (not exceeding 5mm).

Prepare multiple sets of side plates and inspect them each time the mill stops. Replace or adjust them if wear or excessive gap is found.

Monitor the elevator's current during normal production, ensuring it does not exceed 190A. If it does, this indicates the side plate gap is too large or worn.

Use wear-resistant welding rods to overlay the surface of the side plates, enhancing their durability.

After implementing these measures, the elevator's current decreased, and the efficiency of the roller press improved significantly.

1.2 Retrofit the Single Feed Chute of the Roller Press into the V-Type Classifier

The single feed chute of the roller press into the V-type classifier had poor classification and dispersion effects. This instability led to material collapse when temperatures rose. To address this, Darko modified it into three equally sized chutes to enhance material dispersion, forming a uniform curtain of material and reducing segregation.

1.3 Stabilizing Material Pressure

Due to excessive moisture in mixed materials, Darko mandated the cleaning of pneumatic gates and electric valves during each shutdown to prevent build-up and ensure smooth material flow. They also installed cross partition brackets at the top of the weighing silo to ensure uniform weighing and prevent material collapse.

1.4 Proper Adjustment of Feed Gate Openings

Darko adjusted the feed gate openings based on the material conditions in the roller press's weighing silo. They ensured the silo remained stable at about 2/3 full to maintain uniform feeding and stable current during roller press operation.

1.5 Ensuring Effective Compression on the Roller Press Rollers

After six months of use, the composite surface of the roller press showed significant wear in the center, reducing efficiency. After evaluation, Darko modified the roller system, replacing it with new columnar rollers and side plates. This new structure offers high hardness and toughness, significantly improving wear resistance and grinding efficiency while lowering maintenance costs. After the retrofit, the roller press operated stably and increased the mill's hourly output.

After a series of adjustments, the input material for P·O42.5 cement reached an 80μm sieve residue of about 50%, creating the necessary conditions to enhance the mill's output.

02 Measures for Increasing Production and Reducing Consumption of the Mill System

2.1 Proper Grinding Media Distribution

After successfully adjusting the roller press system, the mill focused on enhancing grinding efficiency, reducing current, and maintaining a proper particle size distribution of the finished cement. Darko achieved this by optimizing the grinding media distribution, increasing impact frequency, and improving grinding efficiency.

2.2 Improving Internal Ventilation and Retrofitting the Partition Plates

The existing partition plates had defects that affected the mill's ventilation. Darko technically retrofitted the partition plates in the first chamber, using new anti-blocking double-layer partition screens. This significantly improved ventilation and material flow capacity.

2.3 Controlling the Flow Rate in the Second Chamber

To activate the grinding media in the second chamber and reduce material flow rate, Darko raised the retaining ring. This enhancement improved the grinding capacity of the second chamber and increased hourly output.

2.4 Semi-Final Grinding Retrofit

To lower production costs and enhance economic efficiency, Darko performed a semi-final grinding retrofit on the grinding system. They replaced the original classifier, enhancing the cement yield.

2.5 Other Measures

Strengthen mill management and operation to ensure optimal equipment performance.

Pay attention to system ventilation and provide timely feedback on raw material moisture content to ensure quality.

Optimize clinker quality to enhance the mill's output and quality.

03 Results After the Retrofit

The energy consumption of grinding systems is a key indicator of their performance. Currently, grinding technology is evolving towards complete ball-free systems, such as vertical mills or roller presses, and larger equipment. With advancements in cement technology, the overall energy consumption in cement production shows the following trends:

Ball Mill Era: Over 100 kWh/t

Partial Bed Grinding Era: About 90 kWh/t

Ball-Free Era: Below 80 kWh/t

This trend indicates that grinding technology is continuously improving to achieve lower energy consumption and higher production efficiency.

Methods to Reduce Energy Consumption in Ball Mill Systems

1. The Impact of Materials on Grinding System Energy Consumption

1.1 The Effect of Material Grindability

The yield of the cement grinding system closely relates to the grindability of clinker. The mineral composition and cooling rate of the clinker affect its grindability. For instance, clinkers with high C3S content and low C4AF content typically exhibit good grindability. Conversely, clinkers with high C2S and C4AF content lead to higher energy consumption. Therefore, optimizing the mineral composition and cooling conditions of clinker effectively reduces energy consumption.

1.2 The Impact of Material Particle Size

Reducing the particle size of the feed material significantly increases the mill's yield, thereby lowering energy consumption. When the average particle size of the feed material decreases from 30 mm to 2 mm–3 mm, the mill's yield can increase by over 50%. Additionally, employing a "more crushing, less grinding" pre-crushing process effectively minimizes over-grinding and improves mill efficiency.

1.3 The Impact of Material Temperature and Moisture

When the temperature of the feed material exceeds 80 °C, the internal temperature of the mill may exceed 120 °C, leading to reduced grinding efficiency and increased energy consumption. Therefore, it is essential to control the temperature of the clinker and maintain the moisture content between 1.0% and 1.5% to ensure stable mill operation.

2. The Impact of Mill Ventilation on Energy Consumption

Enhancing ventilation within the mill reduces buffering effects and increases material flow speed, thus lowering temperature and increasing mill yield. The airflow speed inside the mill should be maintained between 0.9 and 1.1 m/s to avoid over-grinding and increased energy consumption. Additionally, improving the sealing of the system to reduce air leaks is crucial for lowering energy consumption.

3. Regular Maintenance and Inspection of the Mill

Regularly checking and maintaining the mill and optimizing parameters such as ball charge, filling rate, and selection efficiency can help maintain system stability and high operational efficiency. Proper adjustment of the grinding body configuration is necessary to achieve optimal mill performance.

4. The Impact of Particle Size Distribution on Product Quality and Energy Consumption

The optimal particle size distribution for cement ranges from 3 μm to 32 μm, with fine particles not exceeding 10%. Regular analysis of particle size distribution helps adjust ball charges in a timely manner, improving mill efficiency and reducing energy consumption.

Optimization of Combined Grinding Systems

In traditional combined grinding systems, roller presses and ball mills undertake different grinding tasks. By optimizing the management of ball mills, we can effectively reduce energy consumption and enhance cement quality.

Advantages of Roller Presses: Increasing the working pressure of the roller press significantly boosts yield under stable operating conditions.

Increase in Total Surface Area of Steel Balls: Adjusting the diameter and quantity of steel balls enhances the grinding capacity of the mill, thus improving grinding efficiency.

Adjustment of Mill Structure: Shortening the coarse grinding chamber and extending the effective length of the fine grinding chamber helps improve the mill's fine grinding capability.

Methods to Reduce Energy Consumption in Vertical Mill Systems

Vertical mills are efficient and energy-saving grinding equipment. Their energy consumption mainly comes from the main motor and the circulating fan. Here are suggestions to lower energy consumption in vertical mill systems:

1. Selection of Optimal Energy Parameters

Operators should adjust operational parameters based on trends in system parameters to achieve high output and low energy consumption.

2. Rational Use of System Airflow

Controlling the airflow of the mill and minimizing air leaks can effectively reduce the energy consumption of the circulating fan.

3. Adjustment of the Material Retaining Ring

Regularly checking and adjusting the height of the material retaining ring avoids inefficient grinding due to improper material layer thickness.

4. Increasing Yield and Equipment Operating Rate

Ensuring continuous operation of equipment and avoiding unnecessary shutdowns help improve stability and reduce energy consumption.

Conclusion

Every process and step in cement production holds potential for reducing energy consumption. By optimizing the grinding system comprehensively, we can significantly lower energy consumption, reduce production costs, and enhance market competitiveness. As professionals in the cement industry, mastering energy-saving technologies and management methods will contribute to achieving sustainable development goals.

S Cement Plant is a modern dry-process cement plant. It uses advanced grinding equipment and technology. The plant employs a CKP vertical mill and a ball mill in a closed circuit system. The CKP mill is CKP-170, and the ball mill has dual chambers with specifications of φ3.9m×12m. It features a cyclone separator. The system's capacity is 115t/h×2.

Clinker and gypsum go through a crusher and break down to particles of ≤40mm, which make up over 95%. They are fed into the CKP mill. The material from the CKP mill contains over 95% of particles ≤10mm. About 10% of this material returns to the CKP mill, while roughly 90% moves to the ball mill along with the separator's return. The ball mill's output combines with fly ash and enters the separator. The separator achieves an efficiency of about 60%, with a circulation load rate of approximately 260%. Most of the cement produced is P.O 42.5R, with a small amount of P.II 42.5R. The average power consumption for both types is 39 kWh/t, using a grinding aid that accounts for 0.02% to 0.03% of the cement weight.

Quality Control Methods and Experience in the Cement Grinding Process

1. Quality Control Methods

The plant uses imported German negative pressure sieves to measure the residue at 15μm, 20μm, 32μm, 45μm, and 63μm based on Japanese methods. The German sieves have a sieve size with an inner diameter of 70mm and a sample weight of 1g. This design allows for a larger airflow during operation, preventing clogging of the sieve holes. The device can complete the measurement of 32μm residue in 8-10 minutes and 45μm residue in 4-6 minutes. It has high machining precision, low failure rates, easy operation, short measurement time, and stable, accurate results, making it suitable for routine production control.

Many domestic cement companies use laser particle size analyzers to measure the particle size distribution of cement. This plant conducted parallel tests using both the negative pressure sieve and the laser analyzer on the same sample. The results showed that the laser analyzer yielded consistent results with the negative pressure sieve for particles over 10μm. However, for particles under 10μm, the laser analyzer's results were slightly higher. This difference occurs because very fine particles tend to agglomerate due to van der Waals forces, making them difficult to disperse in negative pressure sieving. While the laser analyzer is suitable for periodic checks, its complexity, longer operation time, and higher failure rates make it unsuitable for routine quality control.

2. Quality Control Experience

2.1 Fineness

The plant uses the 32μm residue as a routine control basis for the grinding process. When the 32μm residue is within the target control range, the 80μm residue is stable at 0.2% to 0.4%. However, due to equipment failure, the 32μm residue occasionally fluctuated from the target of 16% to 20%. Testing this batch of cement showed a 28-day compressive strength drop of about 4MPa, indicating that the 80μm residue does not effectively reflect the grinding condition. Therefore, using 32μm or 45μm residue as quality control indicators is appropriate.

2.2 Specific Surface Area

Although the plant measures the specific surface area every 4 hours, these measurements serve only as reference points and do not guide routine control. Statistical analysis reveals no strong correlation between strength and specific surface area. Thus, using specific surface area as a control basis is too rough.

2.3 Particle Distribution

The particle size distribution of cement is closely related to its physical properties, especially strength. Experience shows that using 32μm or 45μm residue effectively reflects particle distribution and should be included in routine control.

2.4 Grinding Aids

The plant adds a grinding aid that accounts for 0.02% to 0.03% of the cement weight during grinding. This addition proves effective. There was a brief interruption of the grinding aid, and although the 32μm residue remained within control limits, the particle distribution changed significantly, leading to a noticeable drop in strength.

Conclusion

1.The cement grinding equipment and technology are suitable. The cement's particle distribution is close to the ideal, resulting in improved strength.

2.Particle distribution significantly affects cement's physical properties, particularly strength. Using 32μm or 45μm residue as quality control indicators is appropriate.

3.The combination of vertical and ball mills is an effective cement grinding solution, producing high-quality products with reasonable power consumption.

4.Proper use of grinding aids improves the cement's particle distribution and reduces the quantity of particles smaller than 3μm.

5.Compared to laser particle size analyzers, negative pressure sieves are more suitable for routine quality control.

System Problems

China Huaxing has a combined open-circuit grinding system composed of a roller press, a dispersion classifier, and a cement ball mill:

Roller Press: HFCG160-140, diameter Φ1600 mm, width Φ1400 mm, rotating speed 18.75 r/min, design capacity 670–780 t/h.

Dispersion Classifier: Model SF650/160, design capacity 700–850 t/h.

Ball Mill: Φ4.2 m × 13 m two-bin mill, rotating speed 15.8 r/min, design capacity 150 t/h.

Main Issues Encountered

Metal Impurities: Introduced by material and equipment wear, causing frequent vibrations in the roller press and leading to spalling of the roller surfaces. The accumulation of metal impurities creates a buffering effect on the grinding, resulting in accelerated wear and deteriorating efficiency.

Low Efficiency of the Dispersion Classifier: Rapid wear and difficulty in grade control make it challenging to regulate the fineness of entering material. High moisture content can lead to clogging of sieve plates, preventing normal production.

Clogging Issues: Coarse fineness of entering material clogs the discharge grate's gaps, causing poor ventilation, material return at the mill head, environmental contamination, and reduced production capacity.

Retrofitting Program

1. Installation of Iron Removers and Metal Separators

Increase iron removal testing for raw materials upon delivery. Install iron removers at each raw material feeding point, lowering the height between the iron remover and the material surface to enhance the iron removal effect.

Install a metal separator to detect any metal not removed by the iron remover. Detected metal will be separated using a vibrating screen at the conveyor belt head for manual retrieval.

Install a pipeline iron remover at the coarse powder discharge chute of the V-type classifier to ensure continuous removal of iron slag from the system.If you require any further information, please contact us.

2.Retrofitting of Roller Press & Breaking Classifier

2.1 Upgrading the Dispersing Classifier to a Two-Stage Small V-Type Powder Classifier

The original dispersion classifier has the following deficiencies:

Low Classification Efficiency: Approximately 22%, resulting in coarse fineness. Sieve residue reaches 55% with particles up to 8 mm.

High Maintenance Costs: The mechanical classification leads to increased costs.

Poor Material Adaptability: Reduced classification ability with high moisture content and inadequate handling of material changes.

The system has been upgraded to a two-stage small V-type classifier. The material pressed by the roller press is conveyed to the first-stage classifier. Qualified material is sent to the ball mill, while return material enters the second-stage classifier for further sorting.

Advantages of this System:

Low energy consumption (total installed power of 200 kW)

Low investment

High classification efficiency (87%)

2.2 Upgrade of Material Stabilization and Pressure Stabilization for the Roller Press

The HFCG160-140 roller press has the following issues:

Manual feeding device adjustment lacks central control.

Poor performance with a low fine powder content (about 15%) and low working current.

Constant pressure control system does not auto-adjust roller gap based on material feed conditions.

To solve the above defects, Darko upgraded the roller press system through a number of new technologies. The upgrade plan includes:

Modification of Feeding Device: A new multi-directional feeding device ensures stable roller operation.

Addition of a Roller Gap Adjustment Device: Introduces a constant pressure and roller gap control system, minimizing variations.

Replacement of Hydraulic System: Upgraded to include damping and stroke adjustment valves for improved stability and performance.

3.Modification of Ball Mills

Transforming the Feeding Device: The new device incorporates a five-blade spiral feeder and a deceleration buffer plate to enhance grinding efficiency. Lightweight and Transformation of Lining Plates: New lighter lining plates improve ball-carrying capacity and reduce power consumption. Using Anti-Clogging Grates: Modifications to sieve holes increase material passage capacity and prevent over-grinding.

4.Upgrade of the Dust Collector Ash Return Discharge Point

Cement mills are key equipment in cement plants, primarily responsible for grinding cement raw materials. Steel balls inside the cement mill crush these raw materials to the required fineness. The efficiency, yield, and energy consumption of cement mills depend on the characteristics of the internal steel balls. Additionally, the operational status of the cement mill and the grinding efficiency directly affect the final quality of the cement.

In the cement production process, the wear of steel balls directly impacts the efficiency and quality of cement mills. Regularly replacing and supplementing these steel balls is crucial for maintaining efficient and stable operation in cement manufacturing.

Steel balls, also known as grinding media, are the primary raw material for achieving grinding in cement mills. The size, quantity, and proportion of steel balls during the initial loading are critically important. Any improper addition in these aspects can directly affect the grinding efficiency of the cement mill. During the grinding process, steel balls experience high-intensity wear, leading to issues such as breakage and loss of roundness, which can reduce grinding efficiency. Therefore, ensuring accurate initial ball loading is essential. It's also important to assess the wear of steel balls in the cement mill for timely supplementation, enhancing the production capacity of cement plants.

Steps for Replacing Steel Balls in Cement Mills

1. Preparation

Assess the Current Situation: Regularly check the internal steel balls of the cement mill. Record the degree of wear and the diameter.

Develop a Supplementation Plan: Create a detailed plan based on the wear situation and production needs. Include the supplementation cycle, required specifications, and quantities of steel balls.

Acquire Appropriate Steel Balls: Ensure the purchased steel balls meet quality standards. This will satisfy the production needs of different cement mills.

2. Arrange for Downtime

Notify Relevant Personnel: Inform operators and maintenance staff in advance. This ensures all relevant personnel are aware of the downtime arrangements.

Choose Downtime: Schedule the replacement during low production periods in the cement plant. This minimizes the impact on output.

3.Implementation of Replacement

Clean After Shutdown: After shutting down the cement mill, clean the interior. Use suction equipment to remove residual steel balls and dust.

Remove Old Steel Balls: Remove the old steel balls from the cement mill. You can do this manually or with mechanical equipment. Take care to avoid injury to personnel and damage to equipment.

Load New Steel Balls: Gradually load new steel balls into the cement mill based on the preliminary assessment results. Follow the predetermined proportions.

4. Operation and Inspection

Start the Mill: After loading the new steel balls, restart the cement mill. Monitor the sounds and vibrations to ensure normal operation.

Record Performance Data: After a period of operation, record key parameters. This helps evaluate the performance of the new steel balls.

5. Evaluation and Optimization

Effectiveness Evaluation: Compare production data before and after the replacement. Analyze the impact on the efficiency, quality, and energy consumption of the cement mill.

Optimize Supplementation Plan: Adjust the supplementation cycle and specifications based on the evaluation results. This ensures the production efficiency of the cement plant.

Common Methods for Supplementing Steel Balls

1. Simple Supplementation Method

This method involves regularly supplementing steel balls in cement mills. Even if only one type of larger ball is added, the reasons for wear will cause the balls added later to form a natural size ratio sequentially.

Advantages: Simple and easy to implement, suitable for experienced operators.

Disadvantages: Lacks specificity, may not match the properties of the materials being milled, leading to lower grinding efficiency and higher steel consumption.

2. Reasonable Balancing Supplementation Method

This method is more targeted and includes the following steps:

Material Screening: Screen the new feed and return sand for the cement mill. Calculate the particle size composition of the material to be ground. Group the material by size to determine the required steel ball sizes.

Laboratory Testing: Conduct grinding tests with the material to be ground. This helps determine the appropriate ball size formula for the specific ore.

Optimize Ball Load: Use the particle size composition that yields good grinding results. Base the supplementation calculations on this composition to achieve the ideal ball load in the cement mill.

3. Precise Loading and Supplementation Method

This method is more detailed and includes the following steps:

Mechanical Research: Conduct research on the anti-crushing performance of the material to be ground in the cement mill and measure its uniaxial compressive strength.

Material Screening: Screen the material to determine its particle size composition. Group the material accordingly.

Calculate Ball Size: Use semi-theoretical formulas to calculate the required ball size accurately.

Statistical Mechanics Guidance: Use the relationship between crushing probability and steel ball yield to guide the ball matching process.

Initial Installation Verification: Validate the effectiveness of the initial installation plan through testing.

Supplementation Calculation: Determine the quantity of balls to be added. Use wear calculation methods or graphical methods for this purpose.

Safety Precautions

Wear Protective Gear: Ensure all personnel wear appropriate protective gear during replacement in the cement mill.

Site Management: Set up warning signs and restrict access to the work area for non-participating personnel.

By following these steps and methods to replace and supplement steel balls in cement mills, you can ensure optimal operation for the cement plant. Accurate calculations of the quantities and ratios of steel balls will help maintain the effective operation of the cement mill and improve production capacity.

Product introduction :https://www.cementepc.net/grinding/Cement-ball-mill.html

The rapid development of mineral processing, cement, metallurgy, mineral industry and other industries has driven the application market of ball mill. In order to bring more benefits to us, how to make the ball mill play the greatest advantages.

We know that the ball mill is composed of cylindrical cylinder, end cover, bearing and transmission gear ring, in addition to these parts and directly affect the production and consumption of efficient energy saving ball mill lining and grinding ball!In order to give full play to the advantages of this grinding machine, gm first grasped the lifeblood from its lining plate and grinding ball and then analyzed and manufactured.

The cylinder is often subject to physical and abrasive friction and direct impact, the role of the lining plate is to protect the cylinder less damage.Plate has a flat shape, pressure bar, waveform, step, hemispherical, etc., can be adjusted by changing the form grinding body motion, to increase the crushing degree on material, for a long time in the past, lining board of repair and replacement quantity will increase, so it is very important for the material, common high manganese steel, modified high manganese steel, wear-resistant alloy steel, cast iron, etc., so choose a ideal lining board is top priority.

Practice has proved that the grinding effect of the ball mill with different sizes of mixed media is better than that of single size media.In order to mill high efficiency, must be reasonable placement of the mill ball, let large, medium, small ball proportion is appropriate, if one side will cause too much powder and other phenomena.In order to configure the ball reasonably, the specifications of the mill, the fineness of the product, the internal structure and the characteristics of the grinding materials must be considered.

If the ball mill grinding efficiency increase, we in addition to the lining board with just the ball to consider, consider both hardness and hardness of the ore is not to say that as hard as possible, they three suitable problems, only can match well improve grinding efficiency, let play the biggest advantage of high efficiency and energy saving ball mill, so choose milling machine must see its essence.

Product introduction:https://www.lvssn.com/mill/423.html

1. How to properly operate the ball mill is an important issue in the beneficiation process.

At present, mining developments is relatively hot, and skilled workers are relatively scarce. Many of them have not been formally trained and have been employed, which has caused huge economic losses to mining enterprises. In addition, the operation of grinding is a practical experience in production, and many engineers and technicians are not very clear, and the technical experience in this area cannot be found in various books. To this end, according to the author’s years of experience in production and commissioning guidance and the combination of theoretical and technical, the operation f the grinding machine is elaborated.

2. How to effectively improve the grinding fineness is one of the important links in the beneficiation operation, because the cost of grinding operation is a higher part of the ore dressing plant.

How to effectively and reasonably control the grinding fineness is to directly reduce the ore dressing cost. To improve the economic factors of the plant selection. Grinding fineness is one of the many factors affecting the beneficiation index. The size of grinding fineness directly affects the level of concentrate and the recovery rate of the product. Therefore, the technical operation of the ball miller is important.

　　First, we must fully understand the factors affecting the fineness of grinding. In summary, the factors affecting the fineness of grinding are: raw ore hardness, crushing particle size, grid sieve hole, ore amount, ball mill model, number of steel balls, steel ball size ratio, ball mill inner wear, ball mill speed, grading machine speed, classifier spindle lifting height, classifier blade wear, classifier overflow weir, leveling machine lower opening height, classifier lower opening size, classifier upper opening height, return sand flow size, hall mill the size of the water supply, the size of the water at the discharge port of the ball mill etc.

　　In the case of a certain amount of ore, the size of the flushing at the discharge port and the size of the ore directly affect the fineness of the grinding. In many domestic mines, the grinding automation is not realized. The amount of water is directly carried out by the ball mill. Manual adjustment, because the water flow in these two places is large, it is difficult to see the increase and decrease, so careful observation and fine adjustment must be required. First, we understand that the ball mill water supply increases, the grinding concentration becomes thinner, and the grinding fineness becomes thicker. On the contrary, the ball mill water supply decreases, the grinding concentration becomes larger, and the grinding fineness becomes finer. The flushing water at the discharge port of the ball mill becomes larger, the overflow becomes thinner, and the overflow fineness becomes finer. On the contrary, the flushing water at the discharge port of the ball mill becomes smaller, the overflow becomes thicker, and the overflow becomes thicker. Therefore, under other conditions including the same amount of ore, to improve the fineness of grinding, the ball mill water supply can be reduced, and the flushing water at the ball mill discharge port is increased. It is best to adjust these two conditions at the adjustment of the fineness of the grinding.

3. In addition to the above-mentioned various aspects, the fineness of grinding is also related to the proportion of steel balls added.

How to add steel balls according to the size of the steel ball depends on the diameter of the ball mill, the hardness of the ore, the size of the ore of the scoring mill, the hardness of the steel ball, the speed of the ball mill, and other factors.

　　When the model of the ball mil is determined, the speed of the

ball mill

is also fixed. The hardness of the ore is measurable. The ore particle size of the scoring mill is determined by changing the size of the grid.