Background
Ball mills and SAG mills use liners to protect the mill shell from wear by grinding media (steel balls) and ore. The liner is a consumable that needs periodic replacement β typically every 12β24 months depending on mill size, ore type, and liner material.
Rubber liners entered the market as an alternative to steel and manganese steel liners. They are now widely used, though steel liners remain standard in some applications. Understanding where each material works β and where it doesn't β helps operations make informed liner choices.
How the Wear Mechanisms Differ
Steel liners wear primarily through abrasion and impact. Steel is hard and resists direct abrasion well, but each ball-on-liner impact causes work hardening and micro-fatigue. Over time, the liner surface erodes and the profile changes.
Rubber liners wear differently. Rubber is soft and elastic β it deforms under impact and springs back, dissipating energy rather than resisting it. Wear occurs through tearing and gouging of the rubber surface, but the elastic recovery means the liner absorbs repeated impacts without fatigue cracking. Rubber is not suitable where the wear mechanism is primarily grinding abrasion without cushioning.
Side-by-Side Comparison
| Property | Rubber Liner | Steel/Manganese Steel Liner |
|---|---|---|
| Ball mill (smallβmedium, <8m dia) | Excellent | Good |
| SAG mill (large, >8m dia) | Possible for shell; steel for lifter bars | Standard for lifter bars |
| Maximum ball size suitable | ~80mm diameter | Any size |
| Noise reduction | Significant β 6β12 dB lower | No reduction |
| Weight | ~1/6 of equivalent steel | Heavy |
| Installation time | Faster β lighter pieces | Slower β heavy lifting required |
| Liner change downtime | Shorter | Longer |
| Temperature limit | ~80Β°C continuous | No practical limit |
| Impact resistance | Good for ball sizes to 80mm | Required for large ball/SAG pebble |
| Wear life vs steel | Similar or longer in suitable applications | Standard baseline |
| Cost per set | Comparable or lower | Standard baseline |
Where Rubber Liners Work Well
Ball mills up to 8 meters diameter. Rubber liners are widely used in ball mills of this size. The ball charge is typically 60β80mm diameter or smaller. Rubber handles this impact level well and provides the noise reduction and weight benefits.
Secondary and tertiary grinding. As ore particle size decreases through the grinding circuit, the impact energy per particle decreases. Rubber liners become more effective and more durable as feed size reduces.
Operations in noise-sensitive environments. A rubber-lined ball mill is measurably quieter than a steel-lined mill. If your mill is near a residential area or a noise regulation applies, rubber liners can provide meaningful compliance benefit.
Operations where liner change speed matters. Rubber liner sets are lighter (1/6 the weight of steel equivalent) and can be handled without crane for most pieces. Liner changes take less time. This translates to shorter planned maintenance shutdowns.
Wet grinding circuits. Rubber resists corrosion β steel liners corrode in wet, acidic ore environments, losing both material and profile. Rubber is immune to corrosion.
Where Rubber Liners Are Not Appropriate
SAG mills with large pebble charge. SAG mills process coarse ore with large rocks and steel balls. The impact energy is too high for rubber alone. SAG mills typically use composite liner designs: rubber shell liners with steel or ceramic lifter bars. Pure rubber SAG liners are not standard.
Mills handling balls larger than 80β100mm. When ball diameter exceeds 80β100mm, the impact energy per ball becomes too high for standard rubber to handle without rapid damage. Steel is required in these positions.
High-temperature applications. Above 80Β°C continuous, standard rubber compounds soften. This is unusual in most grinding applications but relevant if process water is hot.
Very hard, coarse ore in primary grinding. When feed top size exceeds 25β30mm entering a ball mill (unusual β usually SAG handles primary), or where the ore is extremely hard and angular, rubber wear rates may be unsatisfactory.
Composite Liner Design
Many mills use rubber and steel in combination:
- Shell liners: Rubber or rubber-backed steel composite
- Lifter bars: Steel (higher impact resistance required for the ball-lifting function)
- End liners (heads): Rubber typically works well here
This combination captures rubber's advantages (noise, weight, corrosion resistance) in the positions where it performs well, while retaining steel where impact demands are highest.
Frequently Asked Questions
Our current steel liners last 18 months. Will rubber liners last as long? In suitable applications (ball mill, appropriate ball size), rubber liners typically match or exceed steel liner life. In some copper and gold ball mill applications, rubber liner life of 24β36 months is achievable. In highly abrasive ores with large balls, rubber may be shorter. We need your specific mill parameters to give a realistic estimate.
How much does liner change downtime reduce with rubber liners? Typically 20β40% faster than equivalent steel liner change. The main saving is in handling speed β rubber pieces are lighter and some can be installed by hand. For large mills where liner changes take 2β3 days, this is a meaningful saving.
Do rubber liners affect grinding efficiency? The liner profile (lifter bar angle and height) determines grinding efficiency, not the liner material per se. A rubber liner set with the same profile as steel will produce the same grinding result. Material selection is a maintenance and cost question, not a process performance question.
Contact Elephant Rubber
We supply rubber mill liners for ball mills in NR and SBR compounds. Contact us with your mill diameter, length, ball charge size, ore type, and current liner life for an assessment of rubber liner suitability.