Morphology Study of Particle Breakage Mechanisms in a Horizontal Stirred Mill: Automated and Manual Point Counting Approaches
- 1 Systems Design Engineering, University of Waterloo, Waterloo, Canada
- 2 Norman B. Keevil Institute of Mining Engineering, University of British Columbia, Vancouver, Canada
Abstract
High-speed stirred mills are utilized to grind particles below 10mm. Grinding sulphide minerals to as low as 10mm achieve adequate mineral liberation for successful downstream mineral processing operations, such as flotation and leaching. Particle breakage mechanism such as fracture or abrasion, determines the morphological surface features of the product particles. It is anticipated that particles, which break along grain boundaries (intergranular) produce rough surfaces, whereas particles that break across the grain boundaries (transgranular) possess smoother surfaces. In this study, particles are ground in a stirred mill and their morphological features were analyzed using automated and manual detection methods. Literature and conventional belief are that high-speed stirred mills break particles by attrition. This paper showed that fracture is also an important breakage mechanism along with attrition. Breakage mechanism is a factor of input stress intensity, in the form of the mill agitator speed, and type of mineral. It is observed that at higher agitator speed galena fractures along the grain boundaries, whereas quartz, abrade across the grain boundaries.
- Singh, V., Dixit, P., Venugopal, R. and Venkatesh, B. (2018) Ore Pretreatment Methods for Grinding: Journey and Prospects. Mineral Processing and Extractive Metallurgy Review, 40, 1-15. https://doi.org/10.1080/08827508.2018.1479697
- Becker, M., Kwade, A. and Schwedes, J. (2001) Stress Intensity in Stirred Media Mills and Its Effect on Specific Energy Requirement. International Journal of Mineral Processing, 61, 189-208. https://doi.org/10.1016/S0301-7516(00)00037-5
- Becker, M. and Schwedes, J. (1999) Comminution of Ceramics in Stirred Media mills and Wear of Grinding Beads. Powder Technology, 105, 374-381. https://doi.org/10.1016/S0032-5910(99)00161-8
- Kwade, A. and Schwedes, J. (2002) Breaking Characteristics of Different Materials and Their Effect on Stress Intensity and Stress Number in Stirred Media Mills. Powder Technology, 122, 109-121. https://doi.org/10.1016/S0032-5910(01)00406-5
- Blecher, L., Kwade, A. and Schwedes, J. (1996) Motion and Stress Intensity of Grinding Beads in a Stirred Media Mill. Part 1: Energy Density Distribution and Motion of Single Grinding Beads. Powder Technology, 86, 59-68. https://doi.org/10.1016/0032-5910(95)03038-7
- Partyka, T. and Yan, D. (2007) Fine Grinding in a Horizontal Ball Mill. Minerals Engineering, 20, 320-326. https://doi.org/10.1016/j.mineng.2006.12.003
- Peukert, W. (2004) Material Properties in Fine Grinding. International Journal of Mineral Processing, 74, S3-S17. https://doi.org/10.1016/j.minpro.2004.08.006
- Bu, X., Chen, Y., Ma, G., Sun, Y., Ni, C. and Xie, G. (2019) Differences in Dry and Wet Grinding with a High Solid Concentration of Coking Coal Using a Laboratory Conical Ball Mill: Breakage Rate, Morphological Characterization, and Induction Time. Advanced Powder Technology, 30, 2703-2711. https://doi.org/10.1016/j.apt.2019.08.016
- Moosakazemi, F., Tavakoli Mohammadi, M.R., Mohseni, M., Karamoozian, M. and Zakeri, M. (2017) Effect of Design and Operational Parameters on Particle Morphology in Ball Mills. International Journal of Mineral Processing, 165, 41-49. https://doi.org/10.1016/j.minpro.2017.06.001
- Tromans, D. and Meech, J.A. (2002) Fracture Toughness and Surface Energies of Minerals: Theoretical Estimates for Oxides, Sulphides, Silicates and Halides. Minerals Engineering, 15, 1027-1041. https://doi.org/10.1016/S0892-6875(02)00213-3
- Celik, I.B. and Oner, M. (2006) The Influence of Grinding Mechanism on the Liberation Characteristics of Clinker Minerals. Cement and Concrete Research, 36, 422-427. https://doi.org/10.1016/j.cemconres.2005.09.011