Cement Vertical Roller Mill

Cement Vertical Roller Mill Introduction

Cement Vertical Roller Mill adopts an advanced external circulation system developed on the basis of vertical mills. Different from the traditional internal circulation design, it is equipped with an independent external classifier. All materials are circulated externally via bucket elevator, eliminating the reliance on hot gas pneumatic conveying at the mill bottom. It features low system resistance and remarkable energy-saving effect, suitable for large-scale production lines such as cement raw meal preparation and industrial solid waste utilization.

Features & Advantages of Cement Vertical Roller Mill

Energy Saving & Consumption Reduction: Mechanical external circulation replaces pneumatic internal circulation, cutting system resistance by around 5000Pa. Fan ventilation power consumption and grinding power consumption drop significantly. Actual measurement from multiple production lines shows comprehensive energy saving ≥30%.

Stable & Reliable: No internal circulating airflow interference inside the mill. Equipment vibration is greatly reduced, material bed stays uniform and stable. Over-grinding is fully suppressed, delivering finished powder with uniform particle size and stable quality.

High-efficiency Drying: Hot air penetrates fully with high thermal efficiency for thorough drying. It can directly process high-moisture raw materials with original moisture ≤20%, without pre-drying equipment in front.

Heavy-duty Wear Resistance: Grinding roller and table are cast from high-chromium alloy wear-resistant material, equipped with thickened wear liners. It features outstanding impact resistance and wear resistance. Adopting heavy steel structure, the machine is robust with annual operation rate ≥95%.

Clean & Eco-friendly: Multi-stage negative pressure closed dust removal with cyclone dust collector + pulse baghouse filter. Dust emission concentration stably ≤10mg/m³. The whole unit runs under fully sealed negative pressure with operating noise ≤85dB(A), meeting national ultra-low emission standards.

Process Flow of Cement Vertical Roller Mill

Material Bed Grinding

Cement raw meal is fed stably and evenly from the batching silo via quantitative feeders and conveying equipment into the cement vertical roller mill. The rotating grinding table drives grinding rollers to perform compression grinding.

Synchronous Drying

While materials are being ground, high-temperature hot air enters from the mill bottom and penetrates upward through the material bed on the grinding table for drying. Without circulating airflow interference inside the mill, wind speed is low, forming a thicker and stable material bed. Hot air achieves sufficient penetration to greatly improve drying efficiency, handling high-moisture materials with moisture ≤20% directly.

External Classification

Ground powder is not classified by internal airflow. Instead, scrapers at the bottom collect powder and discharge it out of the main machine. Materials are mechanically lifted by bucket elevator to the external classifier mounted above the mill for separation. Qualified fine powder is collected as finished product by dust collectors with airflow, while unqualified coarse powder returns to the vertical mill for regrinding to form external circulation. Ball mill can be equipped for staged grinding and multi-stage classification if high-grade cement is required.

VRM Semi-final Grinding System: Composed of external-circulation vertical roller mill and ball mill. The VRM pre-grinds to produce over 40% qualified finished product, and the remaining coarse powder enters ball mill for fine final grinding. Compared with standalone ball mill system (power consumption ≈42kWh/t), semi-final grinding system reduces specific power consumption to 25~28kWh/t. The temperature of finished cement is 70~85℃, water requirement for normal consistency is 25~27%, delivering better particle size distribution and superior cement performance.

Powder Collection & Dust Removal

Multi-stage dust collection system is adopted. Cyclone collector performs primary collection, while electrostatic precipitator or bag filter works as secondary dust collection equipment. It achieves high total product recovery and low exhaust emission concentration. The whole line is controlled by PLC intelligent system with high automation, fully satisfying continuous stable production requirements of cement and other industries.

Application Scenarios of Cement Vertical Roller Mill

Technical Parameters of Cement Vertical Roller Mill

Frequently Asked Questions of Cement Vertical Roller Mill

What is the difference between raw meal final grinding and semi-final grinding process for cement vertical roller mill?

Final Grinding System: The vertical mill adopts external circulation system, featuring simple process, low energy consumption and strong adaptability. It is widely used for grinding cement, slag, raw meal and other materials.

Semi-final Grinding System: Composed of external-circulation vertical roller mill and ball mill. It achieves lower energy consumption, better powder performance and more reasonable particle size distribution. However, it has complex flow, more equipment, higher investment and heavy maintenance workload, mainly used for high-quality cement production.

What to do if the external circulation elevator of cement vertical roller mill breaks down?

Stop feeding immediately, reduce grinding pressure and classifier speed. Resume feeding gradually after current returns normal. Periodic power fluctuation of elevator usually results from bucket falling or deformation; stop mill for inspection. Sudden power drop with no load and tail material level alarm indicates shaft or chain fracture, emergency shutdown for maintenance. High current without alarm is mostly caused by small discharge opening and material backflow at tail wheel, which can be solved by enlarging the diameter and installing buffer receiving hopper.

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

Cement VRM: Equipped with external circulation system, designed for moderate fineness, rational particle gradation and stable product quality to meet strict material performance requirements of cement production.

Coarse Powder VRM: Adopts static classification system with simpler technological flow. Its primary goal is mass production of coarse powder with low fineness requirement at the lowest energy consumption and cost.