A fluid–structure interaction study of upset load from material build-up in raked thickeners

Authors: Lu, Y; Sok, T; Scott, J; Gilbert, C

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DOI https://doi.org/10.36487/ACG_repo/2655_50

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Lu, Y, Sok, T, Scott, J & Gilbert, C 2026, 'A fluid–structure interaction study of upset load from material build-up in raked thickeners', in AB Fourie, M Horta, M Oliveira & S Wilson (eds), Paste 2026: Proceedings of the 28th International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 1-15, https://doi.org/10.36487/ACG_repo/2655_50

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Abstract:
Raked thickeners are critical to mineral processing, yet their design often relies on empirical correlations that fail to predict transient upset loads, leading to over-design or catastrophic mechanical failures. This study presents a high-fidelity, one-way fluid–structure interaction (FSI) framework to quantify transient rake loads induced by extreme material accumulation (island formation) on the floor of a 45 m industrial deep-cone thickener. Transient computational fluid dynamics (CFD) simulations were utilised to model non-Newtonian slurry dynamics and map hydraulic pressure and shear-stress distributions directly onto a finite element analysis (FEA) structural model. Two worst-case upset scenarios were evaluated: an inner island engaged by both short and long rake arms, and an outer island engaged exclusively by the long arm. Results demonstrate that outer island formation induces up to an 88% increase in rotational torque and a 593% increase in nonrotational forces compared to normal steady-state operation. Despite peak rotational torques reaching 366,951 N·m, structural stresses remained below 66 MPa, well within the yield limits of standard structural steels. The findings highlight that while island-induced loads do not immediately threaten structural integrity, the resulting asymmetric forces and severe torque spikes are critical sizing parameters for drive systems and operational control strategies.

Keywords: raked thickener, mineral processing, normal load, upset load, fluid–structure interaction

References:
Albertson, OE & Okey, RW 1992, ‘Evaluating scraper designs’, Water Environment Technology, vol. 4, no. 1, pp. 52–58.
Frost, RC, Halliday, J & Dee, AS 1993, ‘Continuous consolidation of sludge in large scale gravity thickeners’, Water Science & Technology, vol. 28, pp. 77–86.
Gollaher, T, Johnson, JL, Biesinger, MT & Accioly, AHL 2010, ‘Paste thickening tailings – recent examples of a rapidly emerging technology’, Proceedings of the SME Annual Conference, Society for Mining, Metallurgy & Exploration, Englewood.
Gunthert, FW 1984, ‘Thickening zone and sludge removal in circular final settling tanks’, Water Science & Technology, vol. 16,
no. 10–11, pp. 303–316,
Hazen, A 1904, ‘On sedimentation’, Transactions of the American Society of Civil Engineers, vol. 53, no. 2, pp. 45–71,
10.1061/TACEAT.0001655
Lu, YJ, Sok, T, Schoenbrunn, F, Scott, J & Gilbert, C 2024, ‘FSI analysis of mud-rake Interaction in a full-scaled thickener’, Proceedings of the SME Annual Conference, Society for Mining, Metallurgy & Exploration, Englewood.
McCarty, MF & Olson, R 1959, ‘Polyacrylamides for the Mining Industry’, Mining Engineering, vol. 11, no. 1, pp. 61–65.
Ruan, Z, Wang, Y, Wu, AX, Yin, SH & Jin, F 2019, ‘A theoretical model for the rake blockage mitigation in deep cone thickener: a case study of lead-zinc mine in China’, Mathematical Problems in Engineering, vol. 11, pp. 1–7,
2130617
Rudman, M, Paterson, DA & Simic, K 2008, ‘Raking in gravity thickeners’, International Journal of Mineral Processing, vol. 86,
no. 1–4, pp. 114–130,
Rudman, M, Paterson, DA & Simic, K 2010, ‘Efficiency of raking in gravity thickeners’, International Journal of Mineral Processing, vol. 95, no. 1, pp. 30–39,
Schoenbrunn, F 2011, ‘Dewatering to higher densities - an industry review’, in R Jewell & AB Fourie (eds), Paste 2011: Proceedings of the 14th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 19–23,
Sutalo, ID, Paterson, DA & Rudman, M 2003, ‘Flow visualization and computational prediction in thickener rake models’, Minerals Engineering, vol. 16, no. 2, pp. 93–102,
Warden, JH 1981, ‘The design of rakes for continuous thickeners. Especially for waterworks coagulant sludges’, Filtration Separation, vol. 18, no. 2, pp. 113–116.




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