· M i = work index related to the breakage property of an ore (kW h/tonne); for grinding from the product of the final stage of crushing to a P 80 of 750 μm (coarse particles) the index is labelled M ia and for size reduction from 750 μm to the final product P 80 normally reached by conventional ball mills (fine particles) it is labelled M ib.
Bond Ball Mill Work Index For Pure Quartz. A bond ball mill work index may also be used in the simulation and optimisation of existing mills and the associated grinding circuits sample requirements a minimum of 10 kg of material crushed to nominally minus 10 mm is preferred jktech would stage crush the sample to minus 335 mm as required for the ...
work index. The work index, w i, represents the kilowatt hours per tonne required to reduce the material from theoretically infinite feed size to 80 percent passing 100μm . 2. Design Analysis and Calculations Roll Crusher Geometry It is necessary to estimate the maximum size of
Mib Fine material (< 750 µm) work index in tumbling mill circuit(s) (kWh/t) Mic Ore work index in crusher circuits (kWh/t) Mih Ore work index in HPGR circuits (kWh/t) P100 passing size or closing screen aperture (µm) P80 80% passing size of the circuit product (µm) SABC SemiAutogenousBallMillingCrushing SAG SemiAutogenous Grinding
In the prerequisite module entitled "Work Index Efficiency", you have learned about work index analysis* to define overall grinding circuit efficiency. In rod milling, you can use work index analysis to relate design and operating variables to overall circuit efficiency. However, you cannot use work index analysis for the same purpose on ball mill
It includes ball mills, in which the material to be ground is enclosed in a horizontal cylinder or a cone and tumbled with a large number of steel balls, natural pebbles or artificial stones, which crush and break the material. Ball mills have limited appliions in the food industry, but they are used for grinding food colouring materials.
3) In a roll crusher, rolls of diameter 1 m each are set in such a manner that minimum clearance between the crushing surfaces is 15 mm. If the angle of nip is 31 degree, the maximum diameter of the particle (in mm) which can be crushed is _____ .
· A Bond Ball Mill Work Index may also be used in the simulation and optimisation of existing mill(s) and the associated grinding circuit(s). Sample requirements: A minimum of 8 kg of material crushed to nominally minus 10 mm is preferred.
The mill dimensions, (D × L), are × m and it is loaded with kg steel rods 14 to 20 mm diameter. The mill rotates on rolls and its frequency is set to 70 RPM corresponding to 85% of the critical frequency. The mill power is = Watts, calculated by (6). Fi P nally the product is wet screened to find the size d80.
The Bond's standard ball mill is used to determine the work index value of differ ent samples. The Bond work index is defined as the kilowatthours per short ton required to break from infinite size to a product size of 80% passing 100 µm. If the breakage characteristics of a material remain constant over all size ranges, the calcul ated work
the work index depending on the grind size. In this way, work index values are usually obtained for some specific grind size that characterizes the grinding operation to design or under evaluation. This study was carried out in a standard bond ball mill 305 mm x 305 mm size
Ball Mill Operatng Work Index Calculation. Appliion of operating work indices in autogenous power draw of agsag and ball mills note that the ball mill operating work index is applied only on the portion that needs the additional grinding q2 which renders to the agsag mill the credit for the fraction of the material that had been already ground to final product q1
Increased crushed ore quality which is good for the ball mill . Literature Review . Introduction . Crushing plants usually consist of set of machines that are put together to form a process to gradually reduce the size of the processed material until the desired output .
· The Bond's work index values increased as test sieve size decreased. 16. Bond work index is changed with the change in the test sieve size and circulating load. This must be taken into account when energy consumption is calculated according to the Bond formula. unit energy cost extra increased as circulating load decreased from 250%.
that is used has come from a Bond ball mill work index test that has generated a similar value to that input to the "Tumbling mill circuit product P80 final grind" field. If this is not the case the resultant specific energy prediction accurate might be compromised.
rod mill work index has not been de ned as yet. The ball ﬁ mill work index is con rmed at 16 kWh/t. The operating ﬁ work index, though, is in the range of 21 kWh/t to 25 kWh/t showing high inefﬁ ciency. This raises the point that, in some cases, the Bond EF4 oversize factor calculation is .
The ideal gap setting to produce a "fine" crush on my mill might not work at all for your system and process. Your system might require more of a "coarse" crush to work efficiently. Not to mention that grain is an agricultural product and varies in kernel sizes .
The mill product can either be finished size ready for processing, or an intermediate size ready for final grinding in a rod mill, ball mill or pebble mill. AG/SAG mills can accomplish the same size reduction work as two or three stages of crushing and screening, a rod mill, and some or all of the work of a ball mill.