Vertical Roller Mill (VRM) is an energy-efficient grinding equipment widely used in cement, power, metallurgy, chemical industry and other industries. It is mainly used for grinding hard materials such as ore, slag, cement clinker, etc.
1. Structure and composition
• Grinding Table: A horizontally rotating circular plate on which the material is crushed.
• Grinding Rollers: 2-4 conical or cylindrical rollers that apply pressure to crush the material through a hydraulic system.
• Classifier: A dynamic or static classifier that separates qualified fine powder from coarse powder (the coarse powder returns to the grinding table for re-grinding).
• Transmission system: The motor and reducer drive the grinding table to rotate.
• Hydraulic system: Control the pressure of the grinding roller and adjust the grinding intensity.
• Casing and air duct: A sealed structure with a built-in hot air channel for drying wet materials.
2. Working Principle
• Feeding: The material enters the center of the grinding disc through the air-locking feeder.
• Rolling: The grinding roller rolls the material under the action of hydraulic pressure to form a material bed grinding.
• Sorting: The air flow carries the powder upward, the separator separates the fine powder (finished product), and the coarse powder falls back to the grinding disc.
• Drying (optional): Hot air is passed into the mill to dry the wet material (such as slag, coal powder) simultaneously.
3. Core Advantages
• Energy saving: Save 30%-50% of electricity compared to the ball mill, low energy consumption.
• Efficient grinding: Material bed grinding principle, high grinding efficiency.
• Integrated design: Grinding, drying and sorting can be completed at the same time.
• Environmental protection: The closed system reduces dust and has low noise.
• Strong adaptability: can handle high moisture (≤15%) or hard materials.
4. Key parameters
| Parameters | Typical range/example |
| Capacity | 5-300 t/h (cement raw material) |
| Grinding disc diameter | 1.5-6.5 m |
| Main motor power | 500-5000 kW |
| Feed size | ≤5% greater than 50 mm (pre-crushing required) |
| Finished product fineness |
300-500 m²/kg (specific surface area) |
5. Application areas
• Cement industry: grinding raw materials, clinker, slag, coal powder.
• Power industry: preparing coal powder for boiler combustion.
• Metallurgy/chemical industry: grinding slag, phosphate rock, quartz, etc.
6. Maintenance points
• Wear of grinding roller/grinding disc: repair by surfacing welding or replace wear-resistant lining.
• Hydraulic system: check oil pressure and sealing regularly.
• Bearing lubrication: special grease is required for high temperature conditions.
• Vibration monitoring: prevent vibration exceeding the standard due to unstable material layer or foreign matter.
7. Comparison of ball mill
| Features | VRM | Ball mill |
| Energy consumption | Low (~15 kWh/t) | High (~30 kWh/t) |
| Noise | ≤85 dB | ≥100 dB |
| Drying capacity | Synchronous drying is possible | Separate drying equipment is required |
| Maintenance cost | High (many precision parts) | Low (simple structure) |
8. Development trend
• Intelligence: integrated sensors and AI to optimize operating parameters.
• Large-scale: single-machine capacity exceeds 600 t/h (such as cement raw material grinding).
• New Materials: Wear-resistant materials such as tungsten carbide extend component life.
