| Popis: |
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: m i (E)= 0 , E≤E min i A ln (E/K i ), E min i ≤E≤E max i 1, E≥E max i where E min i =K i E max i =K i exp (1/ A ) and K i =C(x i /x o ) −m . In this equation, i is an integer index of a √2 screen size interval of upper size xi; xo is a standard size of 1 mm; Emini is the minimum specific impact energy required to produce significant breakage of feed material of size i and Emaxi is the specific impact energy that breaks all feed material of size i. Ā, C and m are material-dependent constants. Values of Ā=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. |
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