抄録
Grinding Kinetics equation is solved as follows:
R(x, t)=R(x, 0)exp(-Kxnt)……eq(l)
R(x, t) Residue, Oversize with respect to × after t hour ground [-], R(x, 0): Initial residue, Oversize with respect to×[-]
K: Grinding Rate Constant [1/μmnh], n: Uniformity Constant [-], t: Grinding time [h]
This eq(1) was confirmed experimentally using a ball mill. It is also reported that this could be applied to other types of milling system. In case of grinding with a Tower Mill, clarifying the correlations among the effective grinding factors on the rate constant "K" is also very important for its design and operation.
Ball diameter, screw speed and slurry density in the mill are to be considered as the important operating variables. A three-way layout design of experiment was applied and the following information was obtained.
There is no relationship between the rate constant "K" and the uniformity constant "n". Therefore, the rate constant "K" is treated as an index of grindability of a Tower Mill, The uniformity constant "n" is also treated as an index of friability of material on a Tower Mill.
The main effects of the experiment are as follows:
The three factors i.e., ball diameter, screw speed and slurry density, are respectively independent and highly significant for Rate Constant "K".
There are interactions among the three factors.
The above mentioned relationship is given by the following empirical equation:
[K]=8.0×[Cυ]-0.756×[N]0.634×[Bd]-1.215
Cυ: Volumetric slurry density [%], N: Screw speed [m/sec.], Bd: Ball diameter [mm]
