Authors: Kealy, T; Bhattacharjee, P; Griffin, P
Editors: Wu, A; Jewell, R
Conference: 20th International Seminar on Paste and Thickened Tailings, 16-18 June, Beijing
Published: University of Science and Technology Beijing, Proceedings of the 20th International Seminar on Paste and Thickened Tailings, pp.50-56, Beijing
The intention of this work was to assess the suitability of the online rheometer (OLR) as a process control tool for measuring coal paste, fed direct from thickener through an OLR. The aim being to predict the OLR performance on-site for process control measuring complex viscosity, G’ elastic modulus (the ‘solid-like’ component of the paste), G” viscous modulus (the ‘liquid-like’ contribution to flow of the paste) controlled by the local operator. On-site testing was conducted to measure the paste density (kg/m3), and compare with Viscoelastic behaviour of the samples. The instrument and sensors used for the analyses were the Rheology Solutions OLR with a serrated plate and plate sensor to minimise slip. The OLR was installed close to the discharge of the thickener, on a rubber mat to damp vibrations from the plant. Thickener discharged thickened paste, which flowed directly through the OLR from the thickener through a 1” diameter flexible hose. OLR data was compared with incumbent process control technology – on-line density measurement. The results indicate that the complex viscosity measured at low frequency correlates well with the in-line density measurement, whereas the other material functions measured by the OLR can be useful for process control. An example of a possible process control strategy is discussed.
Kealy, T, Bhattacharjee, P & Griffin, P 2017, 'Assessment of on-line rheology as a control tool for thickened tails', in A Wu & R Jewell (eds), Proceedings of the 20th International Seminar on Paste and Thickened Tailings
, University of Science and Technology Beijing, Beijing, pp. 50-56.
Bell, D., Binding, D. and Walters, K. 2006, 'The oscillatory squeeze flow rheometer: comprehensive theory and a new experimental facility', Rheologica Acta, vol. 46, no. 1, pp. 111-121.
Bird, R. B., Armstrong, A. and Hassager, O. 1977, 'Dynamics of polymeric liquids', Wiley, New York.
Blight, G.E. and Bentel, G.M. 1983, 'The behaviour of mine tailings during hydraulic deposition', Journal of the South African Institute of Mining and Metallurgy, vol. 83, no. 4, pp. 73-86.
Clayton, S., Grice, T. and Boger, D. 2003, 'Analysis of the slump test for on-site yield stress measurement of mineral suspensions', International Journal of Mineral Processing, vol. 70, no. 1, pp. 3-21.
Engmann, J., Servais, C. and Burbidge, A.S. 2005, 'Squeeze flow theory and applications to rheometry: a review', Journal of non-Newtonian Fluid Mechanics, vol. 132, no. 1, pp. 1-27.
Gawu, S.K. and Fourie, A. 2004, 'Assessment of the modified slump test as a measure of the yield stress of high-density thickened tailings', Canadian Geotechnical Journal, vol. 41, no. 1, pp. 39-47.
Kempton, H., Bloomfield, T.A., Hanson, J.L. and Limerick, P. 2010, 'Policy guidance for identifying and effectively managing perpetual environmental impacts from new hardrock mines', Environmental Science and Policy, vol. 13, no. 6, pp. 558-566.
Konigsberg, D., Nicholson, T., Halley, P., Kealy, T. and Bhattacharjee, P. 2013. 'Online process rheometry using oscillatory squeeze flow', Applied Rheology, vol. 23., no. 3, pp. 35688
Konigsberg, D., Nicholson, T.M., Halley, P.J. and Ahn, K.H. 2014, 'Technical note: correcting for shear strain in an oscillatory squeeze flow rheometer', Rheologica Acta, vol. 53, no. 2, pp. 103-107.
Leblanc, M., Morales, J.A., Borrego, J. and Elbaz-Poulichet 2000, 'A 4500 years old mining pollution in Southwestern Spain: Long-Term concerns for modern mining', Economic Geology, vol. 95, pp. 655-672.
Pashias, N., Boger, D., Summers, J. and Glenister, D. 1996, 'A fifty cent rheometer for yield stress measurement', Journal of Rheology, vol. 40, no. 6, pp. 1179-1189.
Phan-Thien, N. 1980. 'Small strain oscillatory squeeze film flow of simple fluids’, Journal of the Australian Mathematical Society. Series B. Applied Mathematics, vol. 22, no. 1, pp. 22-27.
Phan-Thien, N., Nasseri, S. and Bilston, L.E. 2000, 'Oscillatory squeezing flow of a biological material', Rheologica Acta, vol. 39, no. 4, pp. 409-417.
Walker, C.I. and Goulas, A. 1984, 'Performance characteristics of centrifugal pumps when handling non-Newtonian homogenous slurries', Proceedings of the Institution of Mechanical Engineers, vol. 198A, pp. 41-49.
Wingstrand, S.L., Alvarez, N.J., Hassager, O. and Dealy, J.M. 2016, 'Oscillatory squeeze flow for the study of linear viscoelastic behavior', Journal of Rheology, vol. 60, no. 3, pp. 407-418.