A New Approach to the Calculation of Work Index and the Potential Energy of a Particulate Material

Elias Stamboliadis, Stamatis Emmanouilidis, Evangelos Petrakis

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DOI: 10.4236/gm.2011.12005                

Abstract

The work index W_i was defined by F. Bond as the specific energy (kWh/ton) required to reduce a particulate material from infinite grain size to 100 microns. The calculation is based on the size-energy relationship e_1,2=C.(1/x₂ⁿ–1/x₁ⁿ ) , which for n = 0.5, x₁ = ∞ and x₂ =100, by definition gives e∞, 100 = W_i and consequently C=10W_i. In theory, for a given material the value found for W_i.should be constant regardless of the measured sizes x₁ and x₂ used to calculate the constant C by measuring the energy e. In practice this is not so due to the fact that n ≠ 0.5 and many correction factors have been proposed to overcome this inadequacy experienced by accepting n= 0.5. The present paper proposes a simple way to calculate the appropriate exponent n using conventional grinding procedures. The same calculation can be used to calculate the true value of Wi and attribute a potential energy state to a material at any size.

Keywords

Work Index, Potential Energy, Grinding

Conflicts of Interest

The authors declare no conflicts of interest.

References

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