search  current discussion  categories  tools & equipment - ball mills

## ball mill practices

### Nikom Chimnok on mon 16 jun 97

In Danisch and Norsker's Self Reliant Potter's series, they advise
filling a ball mill approximately half full of balls.
But recently I attended a workshop lead by a woman trained in Japan, and
she uses a different formula. First she weighs the charge, then weighs
the balls so as to add 1.5-2 times the weight of the charge. This
results in a much smaller volume of balls--the mill is barely a quarter
full.
Can anyone comment on the volume or weight of balls which will yield the
most efficient grinding. I can see how to check it experimentally, but
it would require more screens than I have.

Nikom

### Louis Katz on tue 17 jun 97

BY VOLUME.
According to Cardew for Quartz Limestone feldspar etc., The correct
proportions are
Peebles 55-60%
Charge 20-22%
Water 11-18%

The charge and water will fill the space between the pebbles so the mill
will not be over full.

Critical speed is
29.923 divided by the square root of r Where r is the radius of the mill
in meters.
The correct speed for a mill is between 64 and 87 percent of the critical
speed.

Louis

Louis Katz
Texas A&M University Corpus Campus
lkatz@falcon.tamucc.edu
http://www.tamucc.edu/~lkatz