Vertical mill liners (Vertical Mill Grinding Roll Liners) are wear-resistant protective components installed in key working areas (primarily the grinding table and grinding roll surfaces) inside vertical roller mills (VRMs).
Core Functions:
Wear Protection:
Primary function. During VRM operation, materials (e.g., cement raw meal, slag, coal) are compressed and ground between the grinding table and rolls. This process generates intense friction and impact wear. As the components in direct contact with materials, the liners absorb the majority of wear, protecting the mill’s core structures (typically expensive cast steel parts) from excessive abrasion and extending their service life.
Grinding Force Transmission:
Massive grinding pressure from the rolls is transmitted through the liners to crush materials.
Grinding Trajectory Formation:
Grinding table liner designs (e.g., curved surfaces, grooves) guide materials to form a stable grinding bed, enhancing milling efficiency.
Key Characteristics:
High Wear Resistance:
Fundamental performance requirement, directly determining service life and replacement frequency. Manufactured from special wear-resistant materials with high hardness/toughness (e.g., high-chrome cast iron, Ni-Hard iron, ceramic composites).
High Impact Resistance:
Withstands impact loads from materials and rolls without fracturing.
Excellent Stability:
Maintains dimensional and performance stability under high-temperature/high-pressure operating conditions.
Optimized Structural Design:
Geometry facilitates material flow, stable bed formation, and easy installation/replacement. Common types include:
Grinding table: Segmented blocks, wave liners
Grinding rolls: Tire-type or cylindrical sleeves
Wear Parts:
As direct wear components, liners are critical wear parts in VRM operation. Their service life (measured in operating hours or tons of material processed) is a key indicator of mill efficiency and maintenance costs.
Applications:
Widely used in various VRM models across industries:
Cement: Raw meal mills, cement mills, coal mills
Mining & Metallurgy: Slag micropowder mills, ore grinding mills
Power Generation: Coal pulverization mills
(Models: Loesche, Polysius, Atox, MLS, LM mills, etc.)
