Wow, that could turn into a pretty long dissertation, but from our perspective the first basic step is to characterise the type of wear mechanism that we are dealing with, and select the appropriate compound accordingly. There is no such thing (yet?) as a rubber compound that can practically and economically deal with all types of wear and what we internally here refer to as ‘wear intensity’. We use certain compounds to deal with purely abrasive wear (on the lower end of the intensity spectrum, as in light secondary or tertiary milling applications) and entirely different compounds to deal with what is commonly known as ‘cut and tear’ on the higher end of the spectrum, as seen in SAG and AG applications. For abrasive wear we are in almost all cases going to use a purely natural compound, but to combat cut and tear we will generally use styrene-butadiene rubber (SBR) compounds, and between those extremes (commonly secondary grinding) we will generally use a blend of natural rubber and polybutadiene, the latter being a laboratory re-creation attempt to reproduce natural rubber, but with some significant enhancements, particularly in terms of resilience.

In the trade, we say that all of the compounds we use for mill linings are “carbon filled” but that industry-standard term is a bit deceiving. It would be more correct to say that our compounds are “carbon reinforced”, because it is the extremely fine particles of carbon black dispersed in the molecular matrix that impart high tensile strength, typically in the order of 20 MPa, or if you like ~2900 PSI ultimate, with ultimate elongation generally being around 600%.

There are still some suppliers out there who will truly ‘fill’ their compounds with inorganics like fine clay to bulk them up (to reduce cost) but to do so has hugely negative effects on wear life. None of our mill lining compounds have a specific gravity above 1.15 (some of our tan-colored compounds used to make pump parts actually have specific gravities below 1.0 so they will float in water) but a big clue related to quality is that if you see a mill lining compound with an S.G. above around 1.2 you are most likely looking at an inferior product. (There are exception to this rule, notably polychloroprene [more commonly known as Neoprene] and certain blends of carboxylated nitrile, but these compounds are rarely used to manufacture mill linings.)

PS: Am not knowledgeable enough to come up with this. A friend in the trade is my source.

Nice information to make a best formulation. But SBR and PBR have a poor tear properties compare to NR, PBR has own reliance and abrasion properties good, mill where high tear and cut resistant require than what should be the advisable ratio of above polymer?

Does Rubber liner used in all mill? Rubber liner design, Grinding material,grinding media, grinding process, grinding efficiancy, electricity consumption these parameter how work and affected?

KEDAR - Sandip Trivedi