Template:EssbmEquation

Single-stage Ball Mill Specific Energy Equation

This is a basic equation of the family of Bond/Barratt calculations. It describes specific energy requirement of a most efficient comminution circuit consisting of a multi-stage crushing plant followed by single-stage ball milling. The conventional form of a single-stage ball mill equation requires Bond rod mill work index testing (see Rowland, 2006 for a detailed explanation) to account for the ore hardness in the size range of 10 mm down to about 2 mm.

E_ssbm as a function of feed size F₈₀, transfer size T₈₀ and the work index values at three different sizes:

• Wi_C: the Bond low-energy impact crushing work index, covers 20 mm to 100 mm size range.
• Wi_RM: the Bond rod mill work index, covers 2 mm to 10 mm size range.
• Wi_BM: the Bond ball mill work index, less than 2 mm size range.

There are a series of calibration parameters that correspond to the size ranges listed above. It is useful to think of this model as a hypothetical 3-stage crushing — rod mill — ball mill circuit with a calibration adjustment (1.25) for SAG milling.

• P_C is the hypothetical tertiary crusher product size (default=9400 µm)
• P_R is the hypothetical rod mill product size (default=2100 µm)

Three Rowland Efficiency Factor adjustments are required:

• EF₄^RM is the oversize feed factor for rod milling, and is a function of the hypothetical crusher product size or the larger of work index for crushing and work index for rod milling.
• EF₄^BM is the oversize feed factor for ball milling, and is a function of the hypothetical rod mill product size and the work index for rod milling.

$E_{ssbm}=</noinclude> {{BondWiEquation|Wi=Wi_{C}|F80=F_{80}|P80=9400 }} + {{BondWiEquation|Wi=Wi_{RM}|F80=9400|P80=2100 }}\times EF_4^{RM} + {{BondWiEquation|Wi=Wi_{BM}|F80=2100|P80=P_{80} }} \times EF_4^{BM} \times EF_5<noinclude>$

See list of pages that use this formula:

• Template:BarrattEtotalEquation ‎ (← links)