SEPOR YOUTUBE • JOIN MAILING LIST • VISIT WEBSITE |
Sepor, Inc.
718 N. Fries Ave. Wilmington, CA 90744 USA
INSTRUCTIONS
Connect starting switch to power. Instructions are found on the inside of the starter. Position the
cover facing up by turning the switch to JOG (momentary contactor switch) to rotate the mill.
Alternately, the user can grab the mill by the handle on the lid and manually rotate the drum
into position. Remove the cover and gasket, then insert the sample and the ball charge. Replace
the gasket and cover. Set the counter to the desired number of revolutions, usually 50 for
coarser grinding, 100 for fine grinding. Turn the switch to RUN and press the START button. The
operator can stop the mill at any time by pressing the STOP button or by turning the switch to
the center position.
After the number of desired rotations count is reached, the mill will stop automatically. Turn the
switch to the center position. Using the JOG switch or grabbing the mill by the handle on the lid
or mill, rotate the drum until the cover is facing up. Remove the cover and gasket. Now, using
the handle on the bottom of the mill, or JOG switch, slowly turn the mill 180 degrees, so the
opening is facing the discharge pan. Sample and ball charge will fall into the receiving pan.
After The product is dumped, the ball charge is screened out, the 700 cm
3
of material is
screened on sieves of the mesh size tested, with a coarser protecting screen of 50 US mesh (300
μ
) The undersize is weighed, and fresh feed is added to the oversize to bring its weight back to
that of the original charge. Then, it is returned on to the balls in the mill and ground for the
number of revolutions calculated to pro- duce a 250% circulating load, dumped and re-screened.
The number of revolutions required is calculated from the results of the previous period to
produce sieve undersize equal to 1/3.5
th
of the total charge in the mill.
The locked-cycle grinding test continues until the net grams of sieve undersize produced per mill
revolution reaches equilibrium and reverses its direction of increase or decrease. Then the
undersize product and circulating load are screen analyzed, and the average of the last three net
grams per revolution (Gbp) is the ball mill grindability. The ball mill work index, Wi (kWh/short
ton) is calculated from the following equation (Bond 1961):
1
The mill should be cleaned by either blowing air into it or wiping the interior with a cloth and or
brush.
The FC Bond ball mill is now ready for the next sample.
1
REPRODUCIBILITY OF BOND WORK INDEX WITH DIFFERENT STANDARD BALL MILLS, E. Kaya and
P. C. Fletcher, Phelps Dodge Mining Co and P. Thompson Dawson Metallurgical Lab, Inc.
