Flocculated unclassified tailings settling efficiency improvement by particle collision optimization in the feedwell

Abstract

Efficient thickening of tailings is a prerequisite for the metal mine tailings backfill and surface disposal operation. The effective collision of ultrafine tailings particles in suspension with flocculant molecules is essential for flocs aggregates formation and settling. Unreasonable feeding speed and flocculant adding method will lead to the failure of effective dispersion of flocculant and high particle content in thickener overflow. In this work, the effect of turbulence intensity and flocculant adding method on floc size, strength, and movement characteristics are analysed. Aiming to solve the turbidity increased, a pilot-scale continuous thickening test was carried out. Taking a single particle and multiple flocs of full tailings as the research object, the particle iterative settlement model of flocs was established. The influence of turbulence intensity on collision effect is studied by tracking and simulating particle trajectory. The results show that in the process of single particle settlement, chaos appears in the iterative process owing to particle adhesion which caused by micro action. When the turbulence intensity is 25.99%, the maximum particle size of tailings floc is 6.21 mm and the maximum sedimentation rate is 5.284 cm·s⁻¹. The tailings floc presents a multi-scale structure of particle-force chain system when hindered settling, and the interweaving of strong and weak force chains constitutes the topological structure of particles. The results are applied to a thicker in plant, the flocculant addition mode and feed rate are optimized, and the flocs settling speed and overflow clarity are improved.

Keywords

unclassified tailings / flocculation settling rate / thickener feedwell / turbulence intensity / flocs micro-structure

References

[1] Wu D, Zhao RK, Xie CW, Liu S. Effect of curing humidity on performance of cemented paste backfill. Int. J. Miner. Metall. Mater., 2020, 27(8): 1046.

[2] Zhang BY, He QY, Lin ZB, Li ZH. Experimental study on the flow behaviour of water-sand mixtures in fractured rock specimens. Int. J. Min. Sci. Technol., 2021, 31(3): 377.

[3] Jiang LC, Yang C, Jiao HZ. Ultimately exposed roof area prediction of bauxite deposit goaf based on macro joint damage. Int. J. Min. Sci. Technol., 2020, 30(5): 699.

[4] F.B. Chen, B. Xu, H.Z. Jiao, X.M. Chen, Y.L. Shi, J.X. Wang, and Z. Li, Triaxial mechanical properties and microstructure visualization of BFRC, Constr. Build. Mater., 278(2021), art. No. 122275.

[5] Yin SH, Wang LM, Wu AX, Kabwe E, Chen X, Yan RF. Copper recycle from sulfide tailings using combined leaching of ammonia solution and alkaline bacteria. J. Clean. Prod., 2018, 189, 746.

[6] C.C. Qi and A. Fourie, Cemented paste backfill for mineral tailings management: Review and future perspectives, Miner. Eng., 144(2019), art. No. 106025.

[7] Angle CW, Gharib S. Effects of sand and flocculation on dewaterability of Kaolin slurries aimed at treating mature oil sands tailings. Chem. Eng. Res. Des., 2017, 125, 306.

[8] H.Z. Jiao, Y.C. Wu, H. Wang, X.M. Chen, Z. Li, Y.F. Wang, B.Y. Zhang, and J.H. Liu, Micro-scale mechanism of sealed water seepage and thickening from tailings bed in rake shearing thickener, Miner. Eng., 173(2021), art. No. 107043.

[9] Chen QS, Sun SY, Liu YK, Qi CC, Zhou HB, Zhang QL. Immobilization and leaching characteristics of fluoride from phosphogypsum-based cemented paste backfill. Int. J. Miner. Metall. Mater., 2021, 28(9): 1440.

[10] Zheng X, Xu XH, Xu KL. Study on the risk assessment of the tailings dam break. Procedia Eng., 2011, 26, 2261.

[11] Ng WS, Sonsie R, Forbes E, Franks GV. Flocculation/flotation of hematite fines with anionic temperature-responsive polymer acting as a selective flocculant and collector. Miner. Eng., 2015, 77, 64.

[12] Zhao X, Fourie A, Qi CC. Mechanics and safety issues in tailing-based backfill: A review. Int. J. Miner. Metall. Mater., 2020, 27(9): 1165.

[13] Tan YY, Yu X, Elmo D, Xu LH, Song WD. Experimental study on dynamic mechanical property of cemented tailings backfill under SHPB impact loading. Int. J. Miner. Metall. Mater., 2019, 26(4): 404.

[14] Y.K. Leong, Controlling the rheology of iron ore slurries and tailings with surface chemistry for enhanced beneficiation performance and output, reduced pumping cost and safer tailings storage in dam, Miner. Eng., 166(2021), art. No. 106874.

[15] Buscall R, Scales PJ, Stickland AD, Teo HE, Lester DR. Dynamic and rate-dependent yielding in model cohesive suspensions. J. Non Newtonian Fluid Mech., 2015, 221, 40.

[16] Boger DV. Rheology of slurries and environmental impacts in the mining industry. Annu. Rev. Chem. Biomol. Eng., 2013, 4, 239.

[17] Neelakantan R, Vaezi G F, Sanders RS. Effect of shear on the yield stress and aggregate structure of flocculant-dosed, concentrated kaolinite suspensions. Miner. Eng., 2018, 123, 95.

[18] Benn FA, Fawell PD, Halewood J, Austin PJ, Costine AD, Jones WG, Francis NS, Druett DC, Lester D. Sedimentation and consolidation of different density aggregates formed by polymer-bridging flocculation. Chem. Eng. Sci., 2018, 184, 111.

[19] Z.E. Ruan, Y. Wang, A.X. Wu, S.H. Yin, and F. Jin, A theoretical model for the rake blockage mitigation in deep cone thickener: A case study of lead-zinc mine in China, Math. Probl. Eng., 2019(2019), art. No. 2130617.

[20] Gheshlaghi ME, Goharrizi AS, Shahrivar AA. Simulation of a semi-industrial pilot plant thickener using CFD approach. Int. J. Min. Sci. Technol., 2013, 23(1): 63.

[21] R. Arjmand, M. Massinaei, and A. Behnamfard, Improving flocculation and dewatering performance of iron tailings thickeners, J. Water Process. Eng., 31(2019), art. No. 100873.

[22] C.V. Nguyen, A.V. Nguyen, A. Doi, E. Dinh, T.V. Nguyen, M. Ejtemaei, and D. Osborne, Advanced solid-liquid separation for dewatering fine coal tailings by combining chemical reagents and solid bowl centrifugation, Sep. Purif. Technol., 259(2021), art. No. 118172.

[23] H. Mamghaderi, S. Aghababaei, M. Gharabaghi, M. Noaparast, B. Albijanic, and A. Rezaei, Investigation on the effects of chemical pretreatment on the iron ore tailing dewatering, Colloids Surf. A, 625(2021), art. No. 126855.

[24] Liang GJ, Chen WM, Nguyen AV, Nguyen TAH. Red mud carbonation using carbon dioxide: Effects of carbonate and calcium ions on goethite surface properties and settling. J. Colloid Interface Sci., 2018, 517, 230.

[25] Ballentine F, Lewellyn ME, Moffatt SA. Donaldson D, Raahauge BE. Red mud flocculants used in the bayer process. Essential Readings in Light Metals, 2016, Cham, Springer, 425.

[26] Zheng D, Song WD, Tan YY, Cao S, Yang ZL, Sun LJ. Fractal and microscopic quantitative characterization of unclassified tailings flocs. Int. J. Miner. Metall. Mater., 2021, 28(9): 1429.

[27] Zhou Y, Gan Y, Wanless EJ, Jameson GJ, Franks GV. Interaction forces between silica surfaces in aqueous solutions of cationic polymeric flocculants: Effect of polymer charge. Langmuir, 2008, 24(19): 10920.

[28] Wang DL, Zhang QL, Chen QS, Qi CC, Feng Y, Xiao CC. Temperature variation characteristics in flocculation settlement of tailings and its mechanism. Int. J. Miner. Metall. Mater., 2020, 27(11): 1438.

[29] Qi CC, Fourie A, Chen QS, Zhang QL. A strength prediction model using artificial intelligence for recycling waste tailings as cemented paste backfill. J. Clean. Prod., 2018, 183, 566.

[30] Wu HY, Wang WJ, Huang YF, Han GH, Yang SZ, Su SP, Sana H, Peng WJ, Cao YJ, Liu JT. Comprehensive evaluation on a prospective precipitation-flotation process for metal-ions removal from wastewater simulants. J. Hazard. Mater., 2019, 371, 592.

[31] Jiao HZ, Wang SF, Wu AX, Shen HM, Wang JD. Cementitious property of NaAlO₂-activated Ge slag as cement supplement. Int. J. Miner. Metall. Mater., 2019, 26(12): 1594.

[32] Li H, Wu AX, Wang HJ, Chen H, Yang LH. Changes in underflow solid fraction and yield stress in paste thickeners by circulation. Int. J. Miner. Metall. Mater., 2021, 28(3): 349.

[33] Bürger R, Narváez A. Steady-state, control, and capacity calculations for flocculated suspensions in clarifier-thickeners. Int. J. Miner. Process., 2007, 84(1–4): 274.

[34] Betancourt F, Bürger R, Diehl S, Mejías C. Advanced methods of flux identification for clarifier-thickener simulation models. Miner. Eng., 2014, 63, 2.

[35] Parsapour GA, Hossininasab M, Yahyaei M, Banisi S. Effect of settling test procedure on sizing thickeners. Sep. Purif. Technol., 2014, 122, 87.

[36] Chen QS, Zhang QL, Qi CC, Fourie A, Xiao CC. Recycling phosphogypsum and construction demolition waste for cemented paste backfill and its environmental impact. J. Clean. Prod., 2018, 186, 418.

[37] H.Z. Jiao, S.F. Wang, Y.X. Yang, and X.M. Chen, Water recovery improvement by shearing of gravity-thickened tailings for cemented paste backfill, J. Clean. Prod., 245(2020), art. No. 118882.

[38] Nasser MS, James AE. Compressive and shear properties of flocculated kaolinite-polyacrylamide suspensions. Colloids Surf. A, 2008, 317(1–3): 211.

[39] Bárány S, Meszaros R, Marcinova L, Skvarla J. Effect of polyelectrolyte mixtures on the electrokinetic potential and kinetics of flocculation of clay mineral particles. Colloids Surf. A, 2011, 383(1–3): 48.

[40] Ma X. Effect of a low-molecular-weight polyacrylic acid on the coagulation of kaolinite particles. Int. J. Miner. Process., 2011, 99(1–4): 17.

[41] S.H. Yin, Y.J. Shao, A.X. Wu, H.J. Wang, X.H. Liu, and Y. Wang, A systematic review of paste technology in metal mines for cleaner production in China, J. Clean. Prod., 247(2020), art. No. 119590.

[42] X.M. Chen, X.F. Jin, H.Z. Jiao, Y.X. Yang, and J.H. Liu, Pore connectivity and dewatering mechanism of tailings bed in raking deep-cone thickener process, Minerals, 10(2020), No. 4, art. No. 375.

[43] Y.X. Yang, T.Q. Zhao, H.Z. Jiao, Y.F. Wang, and H.Y. Li, Potential effect of porosity evolution of cemented paste backfill on selective solidification of heavy metal ions, Int. J. Environ. Res. Public Health, 17(2020), No. 3, art. No. 814.

[44] Fettweis M. Uncertainty of excess density and settling velocity of mud flocs derived from in situ measurements. Estuarine Coastal Shelf Sci., 2008, 78(2): 426.

[45] Konkachbaev A, Morley NB, Abdou MA. Effect of initial turbulence intensity and velocity profile on liquid jets for IFE beamline protection. Fusion Eng. Des., 2002, 63–64, 619.

[46] Wang XY, Feng L, Wang SB, Chuan C, Zhang YQ. Spatiotemporal chaos in coupled logistic map lattice with dynamic coupling coefficient and its application in image encryption. IEEE Access, 2018, 6, 39705.

[47] Palmero MS, Livorati ALP, Caldas IL, Leonel ED. Ensemble separation and stickiness influence in a driven stadium-like billiard: A Lyapunov exponents analysis. Commun. Nonlinear Sci. Numer. Simul., 2018, 65, 248.

[48] Oda M, Takemura T, Takahashi M. Microstructure in shear band observed by microfocus X-ray computed tomography. Géotechnique, 2004, 54(8): 539.

[49] Ji YG, Lu QY, Liu QX, Zeng HB. Effect of solution salinity on settling of mineral tailings by polymer flocculants. Colloids Surf. A, 2013, 430, 29.