Rotating drums are commonly used as grinders by inserting balls or rods int
o the drum. They are also employed as a standard measurement device for att
rition and friability, mainly in the pharmaceutical industry. This paper pr
esents a phenomenological study of the behavior of rotating drums and the f
atigue phenomenon. A sensitivity test showed that for potash the drum shoul
d rotate at 30 rpm and the sample weight should be 100 g, so as to maximize
the attrition rate. Further experimentation showed that the crush strength
of the surviving particles changes significantly during the test owing to
fatigue.