Nanobubble-enhanced flotation of auriferous pyrite in gold ore: Behavior and mechanisms

Abstract

Gold ores in the Jiaozhou region of China are characterized by their abundant reserves, low grade, fine dissemination, and challenges in upgrading. Froth flotation, with xanthate as the collector, is a commonly employed method for enriching auriferous pyrite from these ores. This study aimed to develop a more efficient flotation process by utilizing cavitation nanobubbles for a low-grade gold ore. Batch flotation tests demonstrated that nanobubbles significantly enhanced the flotation performance of auriferous pyrite, as evidenced by improved concentrate S and Au grades and their recoveries. The mechanisms underlying this enhancement were explored by investigating surface nanobubble (SNB) formation, bulk nanobubble (BNB) attachment to hydrophobic pyrite surfaces, and nanobubble-induced agglomeration using atomic force microscopy (AFM) and focused beam reflectance measurement (FBRM). The results revealed that nanobubble coverage on the pyrite surface is a critical factor influencing surface hydrophobicity and agglomeration. SNBs exhibited higher coverage on pyrite surfaces with increased surface hydrophobicity, flow rate, and cavitation time. Similarly, BNB attachment on pyrite surfaces was significantly increased with surface hydrophobicity and cavitation time. Enhanced surface hydrophobicity, along with higher flow rates and cavitation times, promoted pyrite particle agglomeration owing to the increased nanobubble coverage, ultimately leading to improved flotation performance.

Keywords

gold / pyrite / flotation / cavitation nanobubble / agglomeration / mechanism

References

[1] S.J. Liu, Y. Geng, Z.Y. Gao, J.Z. Li, and S.J. Xiao, Uncovering the key features of gold flows and stocks in China, Resour. Policy, 82(2023), art. No. 103584.

[2] YangLQ, YangW, ZhangL, et al.. Developing structural control models for hydrothermal metallogenic systems: Theoretical and methodological principles and applications. Earth Sci. Front., 2024, 311239

[3] E. Erkan, Z. Ekmekci, and E. Altun, Comparison of flash flotation and gravity separation performance in a greenfield gold project, Physicochem. Probl. Miner. Process., 58(2022), No. 3, art. No. 146979.

[4] OzunS, Vaziri HassasB, MillerJD. Collectorless flotation of oxidized pyrite. Colloids Surf. A, 2019, 561349

[5] GuoLN, GoldfarbR, WangZL, LiRH, ChenBH, LiJL. A comparison of Jiaojia- and Linglong-type gold deposit ore-forming fluids: Do they differ?. Ore Geol. Rev., 2017, 88511

[6] LaplanteA. Ten do’s and don’ts of gold gravity recovery. Randol Gold & Silver Forum, 200012Vancouver

[7] McGrathTDH, StauntonWP, EksteenJJ. Development of a laboratory test to characterise the behaviour of free gold for use in a combined flash flotation and gravity concentrator model. Miner. Eng., 2013, 53276

[8] SobhyA, TaoD. High-efficiency nanobubble coal flotation. Int. J. Coal Prep. Util., 2013, 335242

[9] TaoD. Role of bubble size in flotation of coarse and fine particles–A review. Sep. Sci. Technol., 2005, 394741

[10] D.P. Tao, Recent advances in fundamentals and applications of nanobubble enhanced froth flotation: A review, Miner. Eng., 183(2022), art. No. 107554.

[11] TaoDP, WuZX, SobhyA. Investigation of nanobubble enhanced reverse anionic flotation of hematite and associated mechanisms. Powder Technol., 2021, 37912

[12] MaFY, ZhangP, TaoDP. Surface nanobubble characterization and its enhancement mechanisms for fine-particle flotation: A review. Int. J. Miner. Metall. Mater., 2022, 294727

[13] LiCW, LiDL, LiX, XuM, ZhangHJ. Surface nanobubbles on the hydrophobic surface and their implication to flotation. Int. J. Miner. Metall. Mater., 2022, 2981493

[14] Z.X. Wu, D.P. Tao, Y.J. Tao, and G.X. Ma, New insights into mechanisms of pyrite flotation enhancement by hydrodynamic cavitation nanobubbles, Miner. Eng., 201(2023), art. No. 108222.

[15] AzevedoA, EtchepareR, CalgarotoS, RubioJ. Aqueous dispersions of nanobubbles: Generation, properties and features. Miner. Eng., 2016, 9429

[16] ZhouWG, NiuJJ, XiaoW, OuLM. Adsorption of bulk nanobubbles on the chemically surface-modified muscovite minerals. Ultrason. Sonochem., 2019, 5131

[17] QiuJStudy on the Formation and Stability of Bulk Nanobubbles, 2017, Shanghai. University of Chinese Academy of Sciences. 33

[18] W.G. Zhou, C.N. Wu, H.Z. Lv, B.L. Zhao, K. Liu, and L.M. Ou, Nanobubbles heterogeneous nucleation induced by temperature rise and its influence on minerals flotation, Appl. Surf. Sci., 508(2020), art. No. 145282.

[19] ZhangFF, DingEF, GuiXH, et al.. Influence of air solubility on the flotation performance of low-rank coal. Langmuir, 2022, 3882467

[20] ZhangXY, WangQS, WuZX, TaoDP. An experimental study on size distribution and zeta potential of bulk cavitation nanobubbles. Int. J. Miner. Metall. Mater., 2020, 272152

[21] LiWJ, LiuS, SongYS, WenJK, ZhouGY, ChenY. Comprehensive recovery of gold and base-metal sulfide minerals from a low-grade refractory ore. Int. J. Miner. Metall. Mater., 2016, 23121377

[22] SunZM, SunCB, WangJZ, YinWZ. Optimization and mechanism of gold-bearing sulfide flotation. Rare Met., 2014, 33363

[23] H. Huang, X. Yang, Z.X. Wu, et al., An investigation of nanobubble enhanced flotation for fly ash decarbonization, Colloids Surf. A, 679(2023), art. No. 132563.

[24] WaltonW. Feret’s statistical diameter as a measure of particle size. Nature, 1948, 1624113329

[25] Y. Ouyang, S. Luo, P.Y. Ren, et al., Synchrotron X-ray computed tomography analysis of the morphological characterization of aluminum alloy powders produced by gas atomization, Powder Technol., 429(2023), art. No. 118904.

[26] P. Forson, M. Zanin, W. Skinner, and R. Asamoah, Differential flotation of pyrite and Arsenopyrite: Effect of pulp aeration and the critical importance of collector concentration, Miner. Eng., 178(2022), art. No. 107421.

[27] X.P. Niu, J.H. Chen, Y.Q. Li, et al., Correlation of surface oxidation with xanthate adsorption and pyrite flotation, Appl. Surf. Sci., 495(2019), art. No. 143411.

[28] ZhangYH, CaoZ, CaoYD, SunCY. FTIR studies of xanthate adsorption on chalcopyrite, pentlandite and pyrite surfaces. J. Mol. Struct., 2013, 1048434

[29] NakhaeiF, IrannajadM. Reagents types in flotation of iron oxide minerals: A review. Miner. Process. Extr. Metall. Rev., 2018, 39289

[30] H.N. Wang, W.Q. Yang, X.K. Yan, L.J. Wang, Y.T. Wang, and H.J. Zhang, Regulation of bubble size in flotation: A review, J. Environ. Chem. Eng., 8(2020), No. 5, art. No. 104070.

[31] ZhouSH, LiPC, ShenHT. Flotation study on a certain gold ore from Liaoning. Non-Ferrous Min. Metall., 2015, 31223

[32] Y.F. Mu, Y.P. Cheng, and Y.J. Peng, The interaction between grinding media and collector in pyrite flotation at neutral and slightly acidic pH, Miner. Eng., 145(2020), art. No. 106063.

[33] ZhangXL, GuXT, HanYX, Parra-AlvarezN, ClarembouxV, KawatraS. Flotation of iron ores: A review. Miner. Process. Extr. Metall. Rev., 2021, 423184

[34] PitaF. True flotation and entrainment of kaolinitic ore in batch tests. Miner. Process. Extr. Metall. Rev., 2015, 364213

[35] KursunH. The influence of frother types and concentrations on fine particles’ entrainment using column flotation. Sep. Sci. Technol., 2017, 524722

[36] KnüpferP, DitscherleinL, PeukerU. Nanobubble enhanced agglomeration of hydrophobic powders. Colloids Surf. A, 2017, 530117

[37] Y.F. Wang, D.Y. Wei, W.Q. Qin, F. Jiao, X.M. Luo, and Z.C. Pan, Effect of nanobubbles on particle flocculation in sodium oleate-calcite flotation system, Miner. Eng., 204(2023), art. No. 108438.

[38] TangCL, MaFY, WuTY, et al.. Study on surface physical and chemical mechanism of nanobubble enhanced flotation of fine graphite. J. Ind. Eng. Chem., 2023, 122389

[39] TomoY, LiQY, IkutaT, TakataY, TakahashiK. Unexpected homogeneous bubble nucleation near a solid-liquid interface. J. Phys. Chem. C, 2018, 1225028712

[40] X.N. Hu, Z. Tong, J. Sha, et al., Effects of flotation reagents on flotation kinetics of aphanitic (microcrystalline) graphite, Separations, 9(2022), No. 12, art. No. 416.

[41] N. Guan, Y. Wang, B. Wen, X.Y. Wang, J. Hu, and L.J. Zhang, The regulation of surface nanobubble generation via solvent exchange on different substrates, Colloids Surf., 676(2023), art. No. 132290.

[42] Z.L. Zou, N.N. Quan, X.Y. Wang, et al., The properties of surface nanobubbles formed on different substrates, Chin. Phys. B, 27(2018), No. 8, art. No. 086803.

[43] YenTH, LinCH, ChenYL. Effects of gas adsorption and surface conditions on interfacial nanobubbles. Langmuir, 2021, 3782759

[44] XuCL, PengSH, QiaoG, GutowskiV, LohseD, ZhangXH. Nanobubble formation on a warmer substrate. Soft Matter, 2014, 10397857

[45] DitscherleinL, FritzscheJ, PeukerU. Study of nanobubbles on hydrophilic and hydrophobic alumina surfaces. Colloids Surf. A, 2016, 497242

[46] BerkelaarRP, SeddonJR, ZandvlietHJ, LohseD. Temperature dependence of surface nanobubbles. Chemphyschem, 2012, 1382213

[47] BaeY, KangS, KimBH, et al.. Nanobubble dynamics in aqueous surfactant solutions studied by liquid-phase transmission electron microscopy. Engineering, 2021, 75630

[48] D. Shin, J.B. Park, Y.J. Kim, et al., Growth dynamics and gas transport mechanism of nanobubbles in graphene liquid cells, Nat. Commun., 6(2015), art. No. 6068.

[49] MirsaidovU, OhlCD, MatsudairaP. A direct observation of nanometer-size void dynamics in an ultra-thin water film. Soft Matter, 2012, 8277108

[50] WangYF, PanZC, LuoXM, QinWQ, JiaoF. Effect of nanobubbles on adsorption of sodium oleate on calcite surface. Miner. Eng., 2019, 133127

[51] MossazS, ColombetD, AyelaF. Hydrodynamic cavitation of binary liquid mixtures in laminar and turbulent flow regimes. Exp. Therm. Fluid Sci., 2017, 80337

[52] W.W. Wang, X.X. Zhang, C.J. Li, et al., Bubble behavior, flow characteristics, and mass transfer enhancement in self-priming Venturi tubes, Chem. Eng. Sci., 270(2023), art. No. 118536.

[53] H.N. Wang, W.Q. Yang, D.L. Li, et al., Enhancement of coal flotation using impact flow conditioning pulp, J. Cleaner Prod., 267(2020), art. No. 122124.

RIGHTS & PERMISSIONS

University of Science and Technology Beijing