CRLM Cement Vertical Roller Mill

Cement Vertical Roller Mill Introduction

The CRLM cement vertical roller mill is an advanced external circulation system developed by Cronus Machinery based on the vertical mill platform. Unlike traditional internal circulation systems, it features an independently external classifier, with all material circulating externally via a bucket elevator, eliminating the need for bottom hot air pneumatic conveying. This results in low system resistance and significant energy savings, making it suitable for large-scale production lines such as cement raw meal preparation and industrial waste utilization.

Cement Vertical Roller Mill Features & Advantages

Energy Saving & Consumption Reduction: The mechanical external circulation replaces pneumatic internal circulation, directly reducing system resistance by about 5,000 Pa, significantly lowering fan ventilation power and overall grinding power consumption. Comprehensive energy savings of ≥30% have been measured in multiple production lines.

Stable & Reliable: With no airflow interference inside the mill, equipment vibration values are significantly reduced, the material bed is uniform and stable, and over-grinding of material is completely suppressed, resulting in uniform and stable product particle size and quality.

High-Efficiency Drying: Hot air penetrates thoroughly with high thermal efficiency, achieving complete drying. It can directly process high-moisture materials with up to 20% inherent moisture, without the need for pre-drying equipment.

Heavy-Duty & Wear-Resistant: The main grinding rollers and table are made of high-chromium alloy wear-resistant castings, equipped with thickened wear-resistant liners, offering excellent impact resistance and wear resistance. The overall heavy-duty steel structure is robust, ensuring an annual equipment operation rate of ≥95%.

Clean & Environmentally Friendly: A multi-stage negative-pressure closed dust collection process using a cyclone collector and a pulse-jet baghouse dust collector ensures stable dust emission concentrations of ≤10 mg/m³. The entire machine operates under full-seal negative pressure with operating noise ≤85 dB(A), meeting national ultra-low environmental emission requirements.

Cement Vertical Roller Mill Process Flow

Cement Raw Meal → Cement Vertical Mill → Bucket Elevator → External Classifier → Qualified Powder → Dust Collector → Finished

Material Bed Grinding

Cement raw meal is stably and evenly fed into the cement vertical roller mill from the batching station via conveying equipment such as weigh feeders. The rotating grinding table drives the rollers for compression grinding.

Simultaneous Drying

While the material is being ground, high-temperature hot air enters from the bottom of the vertical mill and passes upward through the material bed on the grinding table, achieving hot air drying. With no interfering airflow circulation inside the mill and lower air velocity, a thicker and more stable material bed is formed, allowing hot air to fully penetrate and significantly improving drying efficiency. It can directly process high-moisture materials with up to 20% moisture content.

External Classification

The ground powder is not classified by internal airflow but is collected by bottom scrapers and discharged directly from the main unit. It is then transported by a bucket elevator (mechanical lifting) to the external classifier located above the mill for separation: qualified fine powder is carried by airflow to the dust collector as finished product, while unqualified coarse powder is returned to the vertical mill for regrinding, forming an external circulation. For producing high-quality cement, a ball mill can also be equipped for stage grinding and multi-stage classification.

Semi-Final Grinding System: Composed of an external circulation vertical roller mill and a ball mill. The vertical mill pre-grinds and produces over 40% of the qualified finished product, while the remaining coarse powder enters the ball mill for final fine grinding. Compared to a single ball mill system (power consumption ≈42 kWh/t), the semi-final grinding system reduces process power consumption to 25-28 kWh/t, with cement finished product temperature of 70-85°C, standard consistency water demand of 25-27%, and better particle size distribution and cement performance.

Collection & Dust Removal

A multi-stage dust collection system is used, with a cyclone collector for primary collection and an electrostatic precipitator or baghouse dust collector as secondary collection equipment, ensuring high total product recovery and low exhaust emission concentration. The entire line is controlled by a PLC intelligent system with high automation, fully meeting the continuous and stable production requirements of the cement industry.

Cement Vertical Roller Mill Application Scenarios

Cement Vertical Roller Mill Technical Parameters

Frequently Asked Questions About Cement Vertical Roller Mills

What is the difference between final grinding and semi-final grinding processes for cement vertical roller mills?

Final Grinding System: The vertical mill uses an external circulation system, offering advantages such as simple process, low energy consumption, and strong adaptability. It is widely used for grinding various materials including cement, slag, and raw meal.

Semi-Final Grinding System: Composed of an external circulation vertical mill and a ball mill, it offers lower energy consumption, better powder performance, and more reasonable particle size distribution. However, the process is complex, involves more equipment, requires higher investment, and demands greater maintenance work. It is mainly used for producing high-quality cement.

What should be done if the external circulation bucket elevator of a cement vertical roller mill fails?

Immediately stop feeding, reduce grinding pressure, and lower the classifier speed. Gradually resume feeding after the current returns to normal. Periodic power fluctuations of the bucket elevator often indicate bucket detachment or deformation, requiring mill shutdown for inspection. A sudden power drop to no-load with a tail level alarm indicates a shaft or chain break, requiring an emergency system shutdown for repair. Slightly elevated current without an alarm is mostly due to an undersized discharge port or material leakage/return from the tail pulley. This can be resolved by enlarging the port and installing a buffer hopper.

What is the difference between a cement vertical roller mill and a coarse powder vertical roller mill?

Cement Vertical Mill: Uses an external circulation system, pursuing moderate fineness, reasonable particle size distribution, and stable product quality to meet the stringent requirements of cement production.

Coarse Powder Vertical Mill: Uses a static classification system with a simpler process flow. Its primary goal is to produce large quantities of coarse powder with low fineness requirements at the lowest possible energy consumption and cost.