An equation for the breakage of particles under impact

Using data from the literature, the following simple empirical equation is derived for the cumulative mass fraction of particles broken (m) when impacted at a specific impact energy (J/g of impacted mass) of E: [GRAPHICS] In this equation, i is an integer index of a root2 screen size interval of upper size x(i); x(o) is a standard size of 1 mm; E-min, is the minimum specific impact energy required to produce significant breakage of feed material of size i and E-max is the specific impact energy that breaks all feed material of size i. (A) over bar, C and m are material-dependent constants. Values of (A) over bar = 0.235, m = 0.58 and C = 0. 13 J/g were found for particles of limestone in a thin bed impacted by a falling steel ball. The equation shows that smaller particles require a higher specific impact energy than larger particles to give the same fraction of breakage out of the feed size interval. (C) 2003 Elsevier Science B.V. All rights reserved.