I. Basic Requirements for Ball Mill Liners

Ball mill liners are among the most important wearing parts in the mill. Their selection and quality directly affect the mill availability, grinding efficiency, and production cost. The requirements for liners can be summarised as follows:

1. Material Performance Requirements

• Sufficient hardness: The liner surface must have high hardness to resist ploughing, cutting, and extrusion wear from the material. Generally, the working surface hardness should be in the range of HRC 45–55 (varying by compartment), and the hardness should match that of the steel balls – typically 2–3 HRC points lower than the balls.
• Good toughness: Liners must withstand impacts from grinding media without cracking or fracturing. The front compartment, subject to high impact, requires impact toughness ≥ 10–20 J/cm²; the rear compartments, with lower impact, may allow lower toughness (5–10 J/cm²).
• Adequate yield strength: To prevent plastic flow, bulging deformation, or bolt breakage under high stress.
• Wear resistance: After wear, the surface hardness should reach 0.8–1.3 times the hardness of the material being ground to ensure long‑term effective abrasion resistance.
• Heat resistance: For dry or drying mills, liners must withstand elevated internal temperatures without performance degradation.
• Corrosion resistance: For wet mills or when grinding corrosive materials, the liner material should have some corrosion resistance.

2. Dimensional and Structural Requirements

• Liner dimensions are primarily determined by manhole size そして installation convenience:
  • Too large – cannot pass through the manhole; difficult to handle.
  • Too heavy – high installation labour intensity and difficult to secure.
  • Too small – more bolt holes, weakening the shell strength.
• Common liner size reference:
  • Length: 250–500 mm
  • Width: 300–400 mm
  • Thickness: 40–50 mm
  • Weight: 30–50 kg (30–40 kg for small mills)

3. Installation and Operational Requirements

• Liners must fit tightly against the shell to avoid excessive gaps that could wear the shell.
• Bolted connections must be secure, with locking measures to prevent loosening during operation.
• Directional liners (e.g., stepped liners, classifying liners) must be installed in the specified orientation.
• Casting and heat treatment should be free from defects such as porosity, slag inclusions, cracks, or insufficient quenching.
• Service life is generally required to exceed 20,000 hours (international standard).

4. Economic Requirements

• Under the premise of meeting performance, choose a material with reasonable cost, considering the life‑cycle cost (purchase price + replacement frequency + downtime losses).

II. Overview of Common Liner Material Selection

Traditionally, ball mill liners are made from high‑manganese steel (ZGMn13) そして cast iron (white cast iron or alloy white cast iron):

• Cylpeb compartments (fine‑grinding): White cast iron liners may be used due to good wear resistance and low cost.
• Ball compartments (coarse‑grinding): Manganese steel or high‑manganese steel is preferred, as cast iron is too brittle for high‑impact zones.

In recent years, nickel‑hardened alloy liners そして high‑chromium hard alloy liners have been adopted domestically and abroad, with significantly better wear resistance than manganese steel liners. Chromium‑manganese‑silicon alloy steel liners offer even better strength and wear resistance – up to three times that of nickel‑hardened alloys.

III. Advantages and Disadvantages of Rubber Liners

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Disadvantages

IV. Advantages and Disadvantages of Cast Stone Liners

Cast stone liners (also called diabase liners) are made from natural diabase or basalt, processed by melting, casting, crystallising, and annealing.

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Disadvantages

V. Selection Recommendations

Conclusion: When selecting liners, one must comprehensively consider mill size, compartment type, feed material properties, grinding media type, internal temperature, process mode, and cost budget. No single liner is suitable for all conditions – only by selecting materials according to specific circumstances can high quality, energy savings, and high output be achieved.