Requirements for Ball Mill Liners

Anforderungen an Kugelmühlenauskleidungen sowie Vor- und Nachteile von Gummi- und Gusssteinauskleidungen

14. Juli 2026

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 und 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) und 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 und 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

Vorteile

Vorteil	Beschreibung
Light weight	Only 1/3–1/4 of metal liners, reducing shell load and facilitating handling and installation.
Good wear resistance	Under certain conditions (especially wet fine grinding), rubber’s abrasion resistance can surpass metal liners.
Long service life	In the fine‑grinding compartment of wet raw mills, life can be 2–4 times that of metal liners.
Easy installation/removal	Quick to fit and remove, reducing maintenance time.
Geräuscharm	Rubber absorbs impact energy, reducing mill noise by 8–15 dB and improving working conditions.
Lower power consumption	Low friction coefficient reduces motor current and saves energy.
Non‑sticking	Material does not easily adhere to the surface, improving grinding efficiency.

Disadvantages

Disadvantage	Beschreibung
Poor heat resistance	Operating temperature must not exceed 70–80 °C; above this, rubber ages rapidly and wear resistance drops sharply.
Narrow application range	Only suitable for wet raw mills; not for dry or drying mills.
Higher cost	Initial purchase price is higher than ordinary metal liners.
Cushioning effect on grinding media	Absorbs impact energy, weakening the crushing action of balls in the coarse compartment – not suitable for the first compartment.
Not resistant to oil/solvents	Contact with oils or organic solvents accelerates swelling and aging.

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.

Vorteile

Vorteil	Beschreibung
Good wear resistance	Superior to high‑manganese steel under fine‑grinding conditions.
Low ball coating	Smooth surface prevents media from sticking, improving grinding efficiency.
Light weight	Reduces shell load and facilitates installation.
Good corrosion resistance	Resistant to acids and alkalis, suitable for corrosive materials.
Lower cost	Cheaper than white cast iron, offering good economy.

Disadvantages

Disadvantage	Beschreibung
Very brittle, poor impact resistance	Cannot withstand high impact; only suitable for cylpeb compartments oder ball compartments with ball diameter ≤ 40 mm.
Limited operating temperature	Working temperature should be below 150 °C; not suitable for drying mills.
Prone to breakage	Requires careful handling during transport and installation to avoid chipping or cracking.
Limited application	Only used in small tube mills or the fine‑grinding compartments of medium‑long mills.

V. Selection Recommendations

Betriebszustand	Recommended Liner Material	Reason
First compartment of large mills (high impact)	Medium‑carbon low‑alloy steel, medium‑carbon multi‑alloy steel	Good toughness, resists impact cracking
First compartment of small/medium mills	High‑chromium cast iron (small square blocks, single bolt hole)	Good wear resistance, moderate impact
Second and fine‑grinding compartments	High‑chromium cast iron, medium‑carbon multi‑alloy steel	High hardness, abrasion‑dominant
Cylpeb compartment of small mills	White cast iron, cast stone liners	Low cost, low impact
Wet raw mill (fine‑grinding compartment)	Rubber liners	Wear‑resistant, low noise, long life (if temperature <80°C)
Mills grinding corrosive materials	Cast stone liners, high‑chromium cast iron	Good corrosion resistance

Fazit: 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.

Diese Produkte könnten Ihnen ebenfalls gefallen