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
- Minerals pre-crushed to < 3.35 mm and sieved
- Drillcore pre-crushed to < 3.35 mm and sieved
- Half Drillcore pre-crushed to < 3.35 mm and sieved
The Bond Index conforming ball charge consists of:
- 43 x 1.45” balls
- 67 x 1.17” balls
- 10 x 1” balls
- 71 x 0.75” balls
- 94 x 0.61” balls
The optimum number of grinding balls is 285. However, the ball diameters vary due to wear. Therefore, the total ball number should be adjusted from time to time to ensure a total mass of 20.125 grams.
The grinding jar of the Bond Index Ball Mill measures 12″ x 12″ and has well-rounded corners. Module Rod Mill
- Minerals pre-crushed to < 12.50 mm and sieved
- Drillcore pre-crushed to < 12.50 mm and sieved
- Half a drillcore pre-crushed to < 12.50 mm and sieved
The Bond Index conforming rod charge consists of:
- 6 rods of 1.25“ diameter and 21“ length
- 2 rods of 1.75“ diameter and 21“ length
The grinding jar for the Bond Index Rod Mill is 12″ x 24″ in size and has a wave-shaped design.
At least 15 to 20 kg sample material is required to simulate a closed grinding circuit in a ball or rod mill. The Rod Mill Work Index (RWI) is used for particle size determination in a size range from 25 mm down to 2.1 mm whereas Ball Mill Work Index (BWI) is used for the range from 2.1 mm down to 100 µm.Adjustment of grinding parameters:
The operation display permits convenient selection and storage of parameters such as rotation counter, rotation speed, grinding time, start and stop.
- suitable for the determination of Work Index according to Bond
- available modules include Ball Mill and Rod Mil
- easy tilt function to empty the drum
- solid steel frame
- removable sample collector
- convenient parameter setting via display
- funnel with handles
- guide rail allows for ergonomic removal of jar
- separation grid to separate sample from grinding balls (only for Ball Mill)
- grinding jar with gasket for loss-free operation
- solid noise-protection hood with safety switch
- emergency switch
||quantification of grindability of ores and minerals
|Domenii in care se utilizeaza
||geologie / metalurgie, materiale de construcţii, mediu / reciclare
|Material de macinat
|Principiul de reducere a dimensiunii
|Dimensiunea maximă a materialului de macinat
||< 3.35 mm with ball module / 12.50 mm with rod module
||< 100 µm with ball module / 2,100 µm with rod module
|Cantitate maxima de macinat
||min. 15 kg with ball module / min. 20 kg with rod module
||70 min-1 with ball module / 46 min-1 with rod module
|Posturi de macinare
|Material de constructie a elementelor de macinare
|Dimensiuni recipiente de macinare
||21.7 l with ball module / 43.3 l with rod module
|Setarea timpului de macinare
||230 V, 50 Hz
|Conectare sursă de alimentare
|Grad de protecție
|W x H x D (închis)
||1500 x 1200 x 700 mm
||~ 295 kg
Vă rugăm reţineţi:
* în funcție de materialul de alimentare și configurația/setările instrumentului
Principiu de funcţionare
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.
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