TRANSACTION PAPER

 

Comparison between bond crushing energy and fracture energy of rocks in a jaw crusher using numerical simulation

 

 

A. Refahi^I; J. Aghazadeh Mohandesi^II; B. Rezai^II

^IDepartment of Engineering, Zanjan University, Zanjan, Iran
^IIMining and Metallurgical Engineering Department, Amirkabir University of Technology, Tehran, Iran

 

 

---

SYNOPSIS

For predicting the energy consumption during the size-reduction process, the Bond approach is often used. In this work, the PFC3D discrete element method (DEM) software was employed to model the crushing behaviour of some rocks with different mechanical properties in a laboratory jaw crusher. FLAC3D software was adopted to analyze the stress distribution in the rocks. The rocks studied were modelled as granular assemblies in the shape of a sphere and/or a cube located between two jaws, and the work done by the jaws in the crusher was determined. Nine different types of rocks were studied and the energies consumed by the crusher were compared to those of the Bond comminution energy estimated from the Bond index. There is considerable difference between Bond crushing energy and work done by the jaw crusher for rocks. It appears that the Bond approach is not a suitable method for predicting single particle fracture energy done by the crusher. To verify the results obtained from DEM models, the fracture behavior of the crushed rocks was examined and was compared to the PFC3D results. The tensile mode of fracturing is favourably modelled by the PFC3D software while the delamination mode cannot be well modelled by PFC3D software.

Keywords: jaw crusher; discrete element method; crushing energy; Bond index

---

 

 

“Full text available only in PDF format”

 

 

References

1. CUNDALL, P.A. AND STRACK, O.D.L. A discrete model for granular materials. Geotechnique, vol. 1, 1979. pp. 47-56.         [ Links ]

2. MISHRA, B.K. and RAJAMANI, R.K. The discrete element method for simulation of ball mills. Applied Mathematical Modelling, vol. 16, 1992. pp. 598-604.         [ Links ]

3. MISHRA, B.K. and RAJAMANI, R.K. Simulation of charge motion in ball mills: Part 1. Experimental verification. International Journal of Mineral Processing, vol. 40, 1994. pp. 171-186.         [ Links ]

4. CLEARY, P.W. Predicting charge motion, power draw, segregation, wear and particle breakage in ball mills using discrete element methods. Minerals Engineering, vol. 11 (11), 1998. pp. 1061-1080.         [ Links ]

5. CLEARY, P.W. Charge behaviour and power consumption in ball mills: sensitivity to mill operating conditions, liner geometry and charge composition. International Journal of Mineral Processing, vol. 63, 2001. pp. 79-114.         [ Links ]

6. VAN NIEROP, M.A., GLOVER, G., HINDE, A.L., and MOYS, M.H. A discrete element method investigation of the charge motion and power draw of an experimental two-dimensional mill. International Journal of Mineral Processing, vol. 61, 2001. pp. 77-92.         [ Links ]

7. DJORDJEVIC, N. Discrete element modeling of the influence of lifters on power draw of tumbling mills. Minerals Engineering, vol. 16, 2003. pp. 331-336.         [ Links ]

8. RAJAMANI, R.K., MISHRA, B.K., VENUGOPAL, R., AND DATTA, A. Discrete element analysis of tumbling mills. Powder Technology, vol. 109, 2000. pp. 105-112.         [ Links ]

9. CLEARY, P.W. Recent advances in dem modeling of tumbling mills. Minerals Engineering, vol. 14, 2001. pp. 1295-1319.         [ Links ]

10. MORRISON, R.D., CLEARY, P.W., and VALERY, W. Comparing power and performance trends from DEM and JK modeling. SAG 2001, Department of Mining and Minerals Process Engineering, University of British Columbia, Vancouver, 2001. pp. 284-300.         [ Links ]

11. INOUE, T. and OKAYA, K. Grinding mechanism of centrifugal mills-a simulation study based on the discrete element method. International Journal of Mineral Processing, vol. 44-45, 1996. pp. 425-435.         [ Links ]

12. CLEARY, P.W. and HOYER, D. Centrifugal mill charge motion and power draw: comparison of DEM predictions with experiment. International Journal of Mineral Processing, vol. 59, 2000. pp. 131-148.         [ Links ]

13. THORNTON, C., CIOMOCOS, M.T., and ADAMS, M.J. Numerical simulations of agglomerate impact breakage. Powder Technology, vol. 105. 1999. pp. 74-82.         [ Links ]

14. KAFUI, K.D. and THORNTON, C. Numerical simulations of impact breakage of a spherical crystalline agglomerate. Powder Technology, vol. 109, 2000. pp. 113-132.         [ Links ]

15. MISHRA, B.K. and THORNTON, C. Impact breakage of particle agglomerates. International Journal of Mineral Processing, vol. 61, 2001. pp. 225-239.         [ Links ]

16. POTAPOV, A.V. and CAMPBELL, C.S. Computer simulation of impact-induced particle breakage. Powder Technology, vol. 81, 1994. pp. 207-216.         [ Links ]

17. TOMAS, J., SCHREIER, M., GROGER, T., and EHLERS, S. Impact crushing of concrete for liberation and recycling. Powder Technology, vol. 105, 1999. pp. 39-51.         [ Links ]

18. SCHUBERT, W., KHANAL, M., and TOMAS, J. Impact crushing of particleparticle compounds-experiment and simulation. International Journal of Mineral Processing, vol. 75, 2005. pp. 41-52.         [ Links ]

19. WHITTLES, D.N., KINGMAN, S., LOWNDES, I., and JACKSON, K. Laboratory and numerical investigation into the characteristics of rock fragmentation. Minerals Engineering, vol. 19, 2006. pp. 1418-1429.         [ Links ]

20. DJORDJEVIC, N., SHI, F.N., and MORRISON, R.D. Applying discrete element modeling to vertical and horizontal shaft impact crushers. Minerals Engineering, vol. 16, 2003. pp. 983-991.         [ Links ]

21. BERGSTROM, B.H. Crushability and grindability. SME, Min-Proc. Handbook, vol. II, 1985. pp. 3065-3073.         [ Links ]

22. POTYONDY, D.O. and CUNDALL, P.A. A bonded-particle model for rock. International Journal of Rock Mechanics and Mining Sciences, vol. 41, 2004. pp. 1329-1364.         [ Links ]

23. ITASCA CONSULTING GROUP, INC. PFC3D Particle Flow Code in 3 Dimensions, Minneapolis, Minnesota, 1999.         [ Links ]

24. ITASCA CONSULTING GROUP, INC. FLAC3D Fast Lagrangian Analysis of Continua in 3 Dimensions, Minneapolis, Minnesota, 2002.         [ Links ]

25. DONOVAN, J.G. Fracture toughness based models for the prediction of power consumption, product size and capacity of jaw crushers. PhD Thesis, Virginia Polytechnic Institute, USA, 2003.         [ Links ]

26. REFAHI, A., REZAI, B., and AGHAZADEH, J. Use of rock mechanical properties to predict the Bond crushing index. Minerals Engineering, vol. 20, 2007. pp. 662-669.         [ Links ]

27. CSOKE, B., HATVANI, Z., PABANASTASSIOU, D., and SOLYMAR, K. Investigation of grindability of diasporic bauxites in dry, aqueous and alkaline media as well as after high pressure crushing. International Journal of Mineral Processing, vol. 74, 2004. pp. 123-128.         [ Links ]

28. LAJTAI, E.Z., DUNCAN, E.J.S., and CARTER, B.J. The effect of strain rate on rock strength. Rock Mechanics and Rock Engineering, Technical Note, vol. 24, no. 2, 1991. pp. 99-109.         [ Links ]