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The term "grinding" is used when media are processed together with ore in a rotating or oscillating chamber. This imparts maximum contact between the media and the ore, variously employing both impact and abrasion. The grinding media may be lumps or pebbles of the ore itself (autogenous grinding), steel balls, steel rods, or ceramic pebbles.
The process of size reduction is in part based on statistical probabilities. The feed and product material (after grinding) are defined by a particle size distribution: statistically classifying the probability that a particle of a specified size will be present in an ore sample. When material is fed to a grinding mill, there is also a probability that any given piece will be fractured. The challenge in designing a grinding circuit is to select conditions that increase the probabilities of breaking particular sized particles to produce the desired product size distribution.
In general terms, "comminution" is the process of material size reduction in the mining and mineral processing industries.
The selection of an appropriate mill configuration depends on the feed size distribution the desired product size distribution, and other physical properties which define the relative hardness, integrity, and abrasiveness of the material. Some of these other important properties include the Bond Work Index, the SAG index, the crushing work index, and the abrasion index. These properties vary widely from one material to the next and wide variations can frequently be found within different parts of the same ore body. Cost is also a factor. Capital and operating costs, together with expected productive availability and total service life, define your specific size reduction cost. The optimal mechanical method will, of course, vary significantly from one mineral body to the next. Therefore, effectively balancing capital and operating costs requires an experienced, practical understanding of how to use energy efficiently and configure the grinding mill for the best possible wear material service life.
For further information, please contact  grinding(at)outotec.com
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