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Electrostatic Separation as a Characterizing Tool for the Insulation of Conductive Mineral Particles

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DOI: 10.4236/jmmce.2014.23025    4,057 Downloads   4,943 Views   Citations

ABSTRACT

This work deals with a non-conventional use of a drum-type electrostatic separator. Indeed, the electrostatic separation process is used as a tool to evaluate the efficiency of different formulations of insulating coatings surrounding coarse and irregular conducting mineral particles. Our analysis is based on the change of the particle’s distribution in the conductive and the non-conductive pans after the electrostatic separation process. Different coating formulations were tested and we found that only hydrophobic components have to be used and that a composite formulation must be considered to sufficiently increase the coating thickness. Viscous hydrophobic oil combined with talc is a particularly relevant coating formulation for insulating hematite or ilmenite particles. The viscosity of the binder plays a crucial role as it guarantees the necessary cohesion of the coating itself. To evaluate the required thickness to obtain efficient insulating capabilities for the coating surrounding coarse and irregular mineral particles, we linked the experimental volume ratio between the coating and the particles and the theoretical ratio. The experimental volume ratio is calculated using the weights of all the materials used and their respective densities. Whereas, the theoretical one is calculated using the volume the mineral particles would have, considering them all identical, spherical, with a smooth surface and the volume of the coating being uniform with the same thickness on each mineral particle. We found that an efficient insulating coating for hematite particles means a thickness of 9.5% of the average mineral radius, ranging from 125 μm to 1250 μm, resulting in an equivalent insulating thickness of about 48 μm for particles of around 1 mm in diameter. Interestingly, all results originate from the analysis of the change occurring in the particle’s distribution in the different collecting pans of an electrostatic separator.

Conflicts of Interest

The authors declare no conflicts of interest.

Cite this paper

Bébin, P. , Mavrovic, D. and Rochette, A. (2014) Electrostatic Separation as a Characterizing Tool for the Insulation of Conductive Mineral Particles. Journal of Minerals and Materials Characterization and Engineering, 2, 200-215. doi: 10.4236/jmmce.2014.23025.

References

[1] Lindley, K.S. and Rowson, N.A. (1997) Feed Preparation Factors Affecting the Efficiency of Electrostatic Separation. Magnetic and Electrical Separation, 8, 161-173.
http://dx.doi.org/10.1155/1997/70156
[2] Lindley, K.S. and Rowson, N.A. (1997) Charging Mechanisms for Particles Prior to Electrostatic Separation. Magnetic and Electrical Separation, 8, 101-113. http://dx.doi.org/10.1155/1997/96189
[3] Kelly, E.G. and Spottiswood, D.J. (1989) The Theory of Electrostatic Separations: A Review, Part II. Particle Charging. Minerals Engineering, 2, 193-205.
http://dx.doi.org/10.1016/0892-6875(89)90040-X
[4] de Waal, P. and du Plessis, F.E. (2005) Automatic Control of a High Tension Roll Separator. Heavy Minerals, Society for Mining, Metallurgy and Exploration, 1-9.
[5] Yager, T.A. (2012) Radiation Assisted Electrostatic Separation of Semiconductor Materials. WO Patent No. 128745 A1.
[6] Ojiri, K. and Sakai, K. (1978) Removing Rutile from Zircon Electrostatically. US Patent No. 4,131,539.
[7] Venter, J.A., Vermaak, M.K.G. and Bruwer, J.G. (2008) Influence of Surface Effects on the Electrostatic Separation of Zircon and Rutile. The Journal of the Southern African Institute of Mining and Metallurgy, 108, 55-60.
[8] Ravishankar, S., Kolla, H. and Wang, B. (2010) Process for Enhancing Electrostatic Separation in the Beneficiation of Ores. WO Patent No. 051201 A1.
[9] Henderson, R.L. and Allan, G. (2001) Method for Separating Electrically Conductive Mineral Components from Electrically Non-Conductive Mineral Components of an Ore. US Patent No. 6,168,029 B1.
[10] Macholdt, H.-T., Bauer, R. and Zöller, J. (1996) Polyester Salts and Their Use as Charge Control Agents. US Patent No. 5,502,118.
[11] Bébin, P. (2013) Traitement de surface de particules minérales pour l’amélioration de la séparation électrostatique. Rapport d’activités au Ministère des finances et de l’économie du gouvernement du Québec, Centre de technologie minérale et de plasturgie, Thetford Mines.
[12] Owada, S. (2006) Dry Flotation: A Novel Electrostatic Separation by Modifying Particle Surface with Surfactant and Electrolyte. Resources Processing, 53, 29-33. http://dx.doi.org/10.4144/rpsj.53.29
[13] Owada, S. and Yasukawa, K. (1995) Improvement of the Selectivity in Electrostatic Separation by Modifying Particle Surface. Proceedings of the XIX International Mineral Processing Congress—Physical and Chemical Processing, San Francisco, Vol. 2, Chapter 3, Physical Separation, 173-177.
[14] Tanaka, T., Montanari, G.C. and Mulhaupt, R. (2004) Polymer Nanocomposites as Dielectrics and Electrical, Insulation-Perspectives for Processing Technologies, Material Characterization and Future Applications. IEEE Transactions on Dielectrics and Electrical Insulation, 11, 763-784.
http://dx.doi.org/10.1109/TDEI.2004.1349782
[15] Hinata, K., Fujita, A., Tohyama, K. and Murata, Y. (2006) Dielectric Properties of LDPE/MgO Nanocomposite Material under AC High Field. Annual Report Conference on Electrical Insulation and Dielectric Phenomena, Kansas City, 15-18 October 2006, 313-316.
http://dx.doi.org/10.1109/CEIDP.2006.311932
[16] Cheng, F.C. (1994) Insulating Thickness Determination of Polymeric Power Cables. IEEE Transactions on Dielectrics and Electrical Insulation, 1, 624-629. http://dx.doi.org/10.1109/94.311705

  
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