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Comminution (Size reduction)

Comminution (Size reduction). Mechanical comminution. Outer forces. Special forces. Chemical comminution. Leaching and disssolution . acid. biological . Ways of size reduction . smashing. breaking . attrition . splitting . cutting. crunching . CRUSHING dry, + 50 mm.

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Comminution (Size reduction)

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  1. Comminution (Size reduction)

  2. Mechanical comminution Outer forces Special forces

  3. Chemical comminution Leaching and disssolution acid biological

  4. Ways of size reduction smashing breaking attrition splitting cutting crunching

  5. CRUSHING dry, + 50 mm Size reduction GRINDING wet, - 50 mm

  6. Types of intergrowths of minerals regular vein coating oclusion

  7. Methods of separation and optimum particle size in feed

  8. Splitting of brittle particles

  9. Bending metals

  10. Comminution is a separation process

  11. Indices of comminution I = degree of reduction = D/d L = Degree of liberation = eL Mass of free particles of a given component eL = Mass of a given component in feed

  12. Physicomechanical delineation of particle breaking Noice, heat, etc. Er = En + Ep + Einne Energy of stress formation Energy of surface formation Er = 0.5G2 V/E + S Er = 0.5G2 V/E + S Er - breaking energy G - stress at the moment of breaking V - particle volume S - surface area of particle  - surface energy of particle E - Young’s modulus

  13. The Young modulus and surface energy as two principal parameters of comminution. The Young modulus after Lipczyński and co-workers (1984) and www, surface energy after Drzymala (1994)

  14. Empirical delineation of size reduction dEo = - C dd/df(d) Hukki, 1975 dEo - increase of specific (per mass unit) energy of comminution C - constant f(d) - function dependent on particle size dd - change of partcie size or in a simplified version: dEo = - C dd/dn Walker, 1937

  15. Rittinger Bond Kick

  16. Specific solutions of the Waker equation Kick, 1885 n=1 KK ln(D/d) = Eo = Er/m = Er/V d - average size of particles after size reduction, m D - average size of particles before size reduction, m KK - constant  - density of particle, Mg/m3 V - volume of particle, m3 m -mass of particle, kg Er - comminution energy, J Eo - specific energy of size reduction, J/kg (Energy of comminution is proportional to the volume of the particle)

  17. Specific solutions of the Waker equation Bond, 1952 n=1.5 Eo = KB (1/d0.5 -1/D0.5) (Energy of size reduction depends on both volume and surface area of particle)

  18. Specific solutions of the Waker equation n =2 Rittinger, 1857 Eo = KR (1/d -1/D) Eo = Er/V That is Er = KR*(Sd - SD) S - surface area of particle (Comminution energy is proportional to the surface area of particles)

  19. Comminution equipment: crushers and mills Selected devices for size reduction.a) crushing rolls, b) tumbling mills, c) pendular mill, d) hammer mill, e) jaw crusher, f) gyratory crusher

  20. http://www.retsch-technology.com/ jaw crusher

  21. Ball mills http://ball-mill.fam.de/english/Products

  22. Ball mills http://ball-mill.fam.de/english/Products

  23. Rod mills http://ball-mill.fam.de/english/Products

  24. Impact hammer mills http://ball-mill.fam.de/english/Products

  25. Impact crushers http://ball-mill.fam.de/english/Products

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