GRINDING MEDIA TRAJECTORY IN BALL MILLS:

For effective grinding in ball milling, it is important that the media falls on the charge and not on the mill liners.
Therefore, simulation of the grinding media's trajectory not only helps design the lifter but also operate the mill more effectively.
The outermost trajectory of the grinding media can be simulated as a worst case scenario.
The calculations of the friction coefficients are shown in the literature.
The values of 0.05 and 0.2 can be arbitrarily chosen for the static and kinetic friction coefficients, respectively.

To use:

Enter the effective mill and grinding media (balls) diameters and specify their units.

Provide the mill speed either in "rpm" or "percent critical speed".

Enter the mill filling degree and angle of repose.

Enter the static friction coefficient (typically 0.05).

Enter the dynamic friction coefficients (typically from 0.1 to 0.3).

Provide the lifter face angle with respect to the vertical.

Provide the lifter height.

Click on "Run" to do the calculations and plot the media trajectory.

An example can be seen on this Youtube video.

The simulations may require more computing ressources.
Please check the mill speed is not too fast, the mill diameter is correct and "Run" again if your computer does not show the balls' trajectory in the graph.

Input data:

Ball size:		inches centimeters
Effective mill diameter:		feet meters
Mill speed:		% critical speed rpm
Filling degree (%):
Angle of repose (degree):
Static friction coefficient:
Dynamic friction coefficient:
Lifter face angle (degrees):
Lifter height :		inches centimeters