1. Comminution (Size reduction)

3. Special forces Outer forces Mechanical comminution

4. Chemical comminution biological acid Leaching and disssolution

5. Ways of size reduction breakingattritionsmashing splittingcuttingcrunching

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

7. Types of intergrowths of minerals regularvein coatingoclusion

8. Methods of separation and optimum particle size in feed

9. Splitting of brittle particles

10. Bending metals

11. Comminution is a separation process

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

15. Physicomechanical delineation of particle breaking E r = 0.5G 2 V/E +  S E r - 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 E r =  E n +  E p +  E inne E r = 0.5G 2 V/E +  S Energy of surface formation Energy of stress formation Noice, heat, etc.

16. 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) Material Young modulus GN/m 2 = 10 9 Pa=GPa Surface energy* mN/m = 10 –3 J/m 2 Water ~072.8 Ice9.5 (at 268K)***90–120 KCl (silvinite)29.6* 6 97(780 °C) CaF 2 (fluorite)75.8* 6 450 (plane 111) CaCO 3 (calcite)56.5(marble)230 (100) Al 2 O 3 ( corundum)390****580 (2050 °C) C (diamond)1050-1200** ~3700 Ag83923 (995 °C) Au78*****1128 (1120 °C) Cu1201120 (1140 °C) Pb16,2442 (350 °C) SiO 2 50–78 (glass)230 (1400 °C) Granite51.5–61.4– Sand stone34–50– Diabase61–69–

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

18. Kick Bond Rittinger

19. Specific solutions of the Waker equation n=1 K K ln(D/d) = E o = E r /m = E r  /V d - average size of particles after size reduction, m K K - constant  - density of particle, Mg/m 3 V - volume of particle, m 3 E o - specific energy of size reduction, J/kg E r - comminution energy, J m -mass of particle, kg Kick, 1885 (Energy of comminution is proportional to the volume of the particle) D - average size of particles before size reduction, m

20. n=1.5 E o = K B (1/d 0.5 -1/D 0.5 ) Bond, 1952 (Energy of size reduction depends on both volume and surface area of particle) Specific solutions of the Waker equation

21. n =2 E o = K R (1/d -1/D) That is E r = K R * (S d - S D ) S - surface area of particle Rittinger, 1857 (Comminution energy is proportional to the surface area of particles) E o = E r  /V Specific solutions of the Waker equation

23. 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

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

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

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

27. Rod mills

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

29. Impact crushers