The standard Bond grindability test is a closed cycle dry grinding and screening process and it is carried out until the favorable results are obtained.
Ball Mill Grindability = average of last three grinding cycles to give 250% circulating load. Precautions: There should be consistency in compaction of ores in the 700ml test can. This is normally done by shaking. Accurate observations on grinding revolutions are essential. Dry screening procedures should be consistent.
by Ames. Ore grindabihty refers to the ease with which materials can be comminuted and data from grindability tests are used to evaluate crushing and grinding efficiency.Probably the most widely used parameter to measure ore grindability is the Bond work index W; The work index, Wi, is calculated kWh per ton applied in reducing material of infinite particle size to 80% passing 100 microns.
grindability offinematerials without theneedforreference materials. Avalue ofBcanbecalculated from anyBond grindability test,and245teststhatwereconducted atMintek wereexamined todetermine itsvalue.
GRINDABILITY TESTS BOND BALL MILL GRINDABILITY The Bond ball mill grindability test is performed according to the original Bond procedure 4. It requires 10kg of minus 6 mesh material that is preferably prepared at the testing facility, by stagecrushing the sample to 100% passing 6 mesh, but normally less than 5kg are actually used in the
The value of this quantity, denoted the E, was calculated from the results of Bond standard grindability tests on various materials, and an average value of 1425 x 10 e 6 kW h /min was determined. It is suggested that values far removed from this figure indicate that the ores concerned do not conform to the Bond Law of Comminution .
Standard Bond Ball Mill Grindability Test Method Procedure. Here is the old Allis Chalmers Bond Work Index Grindability Test Procedure. The standard feed is prepared by stage crushing to all passing a 6 mesh sieve, but finer feed can be used when necessary. It is screen analyzed and packed by shaking in a 1000 cc graduated cylinder, and the weight of 700 cc is placed in the mill and ground dry at 250 per cent circulating load.
All standard ball mill tests are conductetl at 250 per cent circulating load, and the number of revolutions in the mill necessary to obtain this circulating load at any grind ing period is estimated from the results of the previous period. The number oi net grams of screen undersize produced per revolution of the mill approaches its final equilibrium value after several grinding periods, and this is recorded as the grind ability, or relative ease of grinding, of the sample.
This Grindability Test or Bond Ball Mill Work Index Procedure is used to determine the Bond Work Index of minus six mesh or finer feed ore samples. These equation application methods are used to process lt;1/2 ore samples in a Ball Mill using a standard ball charge. Below describes in general terms the Bond Work Index Procedure used by a Professional Metallurgical Testing Laboratory.