Abstract
Charles'' experimental finding between the exponents of particle size in the conventional energy-size relationship and the size distribution form is dealt with on the basis of comminution kinetics. Within a reasonable range of particle size and grinding time Char- les'' finding was roughly proved, suggesting a validity in assuming the forms of selection and breakage functions.
A new expression of comminution law in terms of the power consumption, rate constant and particle size as time-variant indicates that "work index" or "grindability" cannot be consistent for a specific material. This equation was further rearranged to be a practical scaleup formula for any kind of grinding equipment as
F/KW=x0(t)m
where F is the feed, W the holdup of material crushed, K the rate constant in the selection function and x0(t) the particle size as a function of time, m being a material constant. This is convenient for practical design purposes.
