A detailed overview and knowledge of the characteristics of a raw material is of utmost importance, especially when planning the layout of a crushing plant. In order to minimize all possible risks extensive trials are necessary to obtain information on the properties of the raw materials. A clear definition of the required crushing capacities and the desired product quality can be precisely determined by using the Bond Index test methods. Using the Bond Index test procedures it is possible to calculate crushing / abrasion behavior of mineral samples. This knowledge is essential to define the required ball mill layout and production capacity.
In order to perform the Bond Index Test successfully it is necessary to use pre-crushed sample material as defined below:
Module Ball Mill
|Applications||quantification of grindability of ores and minerals|
|Field of application||construction materials, environment / recycling, geology / metallurgy|
|Feed material||hard, brittle|
|Size reduction principle||friction|
|Material feed size*||< 3.35 mm with ball module / 12.50 mm with rod module|
|Final fineness*||< 100 µm with ball module / 2,100 µm with rod module|
|Batch size / feed quantity*||min. 15 kg with ball module / min. 20 kg with rod module|
|Rotation speed||70 min-1 with ball module / 46 min-1 with rod module|
|No. of grinding stations||1|
|Material of grinding tools||hardened steel|
|Grinding jar sizes||21.7 l with ball module / 43.3 l with rod module|
|Setting of grinding time||digital|
|Drive power||0.75 kW|
|Electrical supply data||different voltages|
|Protection code||IP 50|
|W x H x D closed||1500 x 1200 x 700 mm|
|Net weight||~ 295 kg|
The ball and the rod mill basically have the same concept comprising either a 12x12’’ jar with grinding balls or a 12x24’’ jar with grinding rods.
The jar is attached to a rotating yoke which is driven by a motor and can be placed in three different positions: Upwards for loading, horizontal for grinding, downwards for discharging.
To carry out the Bond Index test the pre-defined number of grinding balls or grinding rods is required. The electronic control integrated in the drive is equipped with an overload protection and permits and controls different speeds.
During the grinding process the difference in speeds between the balls / rods and grinding jar produces an interaction between frictional and impact forces, which releases the required comminution energy. The interplay between these forces produces a very effective degree of size reduction.