Efficient recovery of zinc from mixed sulfide–oxide zinc ore via combined flotation and ammonia leaching

Abstract

Mixed sulfide-oxide zinc ore (MSOZO) is characterized by a low zinc grade, high oxidation rate, and high slime content; consequently, it is difficult to efficiently recover zinc from MSOZO via a single mineral processing method. To address this, a novel method combining flotation and ammonia leaching is proposed for efficient zinc recovery from MSOZO. Results indicated that 91.87% of the zinc sulfides present in MSOZO were enriched into zinc sulfide concentrates with a zinc grade of 26.11% via froth flotation, while 96.54% of zinc was effectively leached from the flotation tailings using NH₃–(NH₄)₂SO₄. The zinc grade in the ultimate tailings decreased to 0.21%, and the comprehensive zinc recovery rate reached 97.64%. The cyclic leaching results showed that zinc leaching reached dynamic equilibrium after nine cycles, with a zinc concentration of 26.08 g/L and a leaching efficiency of 65.34%. Subsequently, more than 99% of Zn²⁺ in the circulating leachate was converted into ZnS precipitates when using (NH₄)₂S as a precipitant. Mechanistically, zinc in the flotation tailings was mainly leached as stable Zn(NH₃)₄²⁺ complexes, and the leaching process was controlled by internal diffusion with an activation energy of 11.37 kJ/mol. Thus, this study provides an efficient approach for zinc recovery from MSOZO.

Keywords

mixed sulfide-oxide zinc ore / froth flotation / ammonia leaching / sulfide precipitation

References

[1] Nayak A, Jena M S, Mandre N R. Beneficiation of lead-zinc ores–a review [J]. Mineral Processing and Extractive Metallurgy Review, 2022, 43(5): 564-583

[2] Li B-b, Zhang G-f, Shi Q. Atomic insights into the interaction mechanism underpinning carbonate ion adsorption in smithsonite flotation [J]. Process Safety and Environmental Protection, 2024, 190: 11-21

[3] Abkhoshk E, Jorjani E, Al-Harahsheh M S, et al.. Review of the hydrometallurgical processing of non-sulfide zinc ores [J]. Hydrometallurgy, 2014, 149: 153-167

[4] Xu H-s, Wei C, Li C-x, et al.. Leaching of a complex sulfidic, silicate-containing zinc ore in sulfuric acid solution under oxygen pressure [J]. Separation and Purification Technology, 2012, 85: 206-212

[5] Rao S, Yang T-z, Zhang D-c, et al.. Leaching of low grade zinc oxide ores in NH₄Cl–NH₃ solutions with nitrilotriacetic acid as complexing agents [J]. Hydrometallurgy, 2015, 158: 101-106

[6] Feng Q-c, Wen S-m, Bai X, et al.. Surface modification of smithsonite with ammonia to enhance the formation of sulfidization products and its response to flotation [J]. Minerals Engineering, 2019, 137: 1-9

[7] Shang Y-b, Tan X. Study of new process technology for low-grade refractory zinc oxide ore [J]. Procedia Environmental Sciences, 2016, 31: 195-203

[8] Zeng P, Wang C-y, Li M-t, et al.. Volatilization behavior of lead, zinc and sulfur from flotation products of low-grade Pb-Zn oxide ore by carbothermic reduction [J]. Powder Technology, 2024, 433: 119185

[9] Zhang F, Shi Q, Zhang G-fan. Effect of Fe³⁺ on sulfidation flotation behavior of anglesite from zinc leaching residue [J]. Process Safety and Environmental Protection, 2025, 193: 472-482

[10] Zhang H-l, Lin S-y, Sun W, et al.. Lead-zinc flotation: A review on nearly six decades of innovations at the Huangshaping Lead-Zinc Mine [J]. Minerals Engineering, 2024, 216: 108907

[11] Wang Y-w, Zhang S-n, Wang L-j, et al.. An unconventional approach for the efficient recovery of iron, cobalt, copper and silicon from copper slag [J]. Journal of Hazardous Materials, 2024, 476: 135168

[12] Liu Z-c, Jiao F, Cui Y-f, et al.. Application and electrochemical depression mechanism of sodium sulfite on the flotation separation of galena–pyrite mixed concentrate in Yiliang typical high-sulfur lead–zinc deposit [J]. Geochemistry, 2025, 85(1): 126219

[13] Zheng Q-f, Dong L-y, Shen P-l, et al.. A novel activation scheme for fine cassiterite flotation by using a metal ion modified collector [J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2025, 710: 136310

[14] Chen Y-g, Sun Y-s, Han Y-X. Efficient flotation separation of lead–zinc oxide ores using mineral sulfidation reconstruction technology: A review [J]. Green and Smart Mining Engineering, 2024, 1(2): 175-189

[15] Wei Q, Dong L-y, Qin W-q, et al.. Efficient flotation recovery of lead and zinc from refractory lead-zinc ores under low alkaline conditions [J]. Geochemistry, 2021, 81(4): 125769

[16] Pan Z-c, Liu Z-c, Xiong J-j, et al.. Application and depression mechanism of sodium sulfite on galena-pyrite mixed concentrate flotation separation: Huize Lead-Zinc Mine, China, as an example [J]. Minerals Engineering, 2022, 185: 107696

[17] Yi Y-h, Li P-x, Zhang G, et al.. Stepwise activation of hemimorphite surfaces with lead ions and its contribution to sulfidization flotation [J]. Separation and Purification Technology, 2022, 299: 121679

[18] Xue J-w, Qu Y-b, Chen Y, et al.. Effective sulfide flotation of cerussite by using trithiocyanuric acid as a novel sulfurizing reagent [J]. Minerals Engineering, 2023, 198: 108087

[19] Zhang S, Xian Y-j, Wen S-m, et al.. Enhancement of xanthate adsorption on lead-modified and sulfurized smithsonite surface in the presence of ammonia [J]. Minerals Engineering, 2022, 189: 107872

[20] Wang H-x, Xie Z, Cai J-p, et al.. Interaction of NH₃·H₂O–2, 5-Dimercapto-1, 3, 4-thiadiazole system with azurite surface and its role in promoting activation flotation [J]. Applied Surface Science, 2024, 656: 159704

[21] Jia K, Feng Q-m, Zhang G-f, et al.. Understanding the roles of Na₂ S and Pb(II)in the flotation of hemimorphite [J]. Minerals Engineering, 2017, 111: 167-173

[22] Liu C, Feng Q-m, Zhang G-f, et al.. Effects of lead ions on the flotation of hemimorphite using sodium oleate [J]. Minerals Engineering, 2016, 89: 163-167

[23] Jia K, Feng Q-m, Zhang G-f, et al.. Improved hemimorphite flotation using xanthate as a collector with S (II) and Pb(II) activation [J]. International Journal of Minerals, Metallurgy, and Materials, 2018, 25(8): 849-860

[24] Cai J-p, Yu X-h, Su C, et al.. Improved azurite sulfurization with ethylenediamine modification and its effects on flotation behaviors: Insight from copper vacancy [J]. Minerals Engineering, 2024, 209: 108636

[25] Yang J, Chen L-z, Wu D-d, et al.. Sodium sulfosalicylate activation mechanism on sulfidation flotation of smithsonite using dodecylamine as a collector [J]. Minerals Engineering, 2023, 192: 107987

[26] Zuo Q, Yang J, Shi Y-f, et al.. Activating hemimorphite using a sulfidation-flotation process with sodium sulfosalicylate as the complexing agent [J]. Journal of Materials Research and Technology, 2020, 9(5): 10110-10120

[27] Hussaini S, Kursunoglu S, Top S, et al.. Testing of 17-different leaching agents for the recovery of zinc from a carbonate-type Pb-Zn ore flotation tailing [J]. Minerals Engineering, 2021, 168: 106935

[28] Kursunoglu S, Kursunoglu N, Hussaini S, et al.. Selection of an appropriate acid type for the recovery of zinc from a flotation tailing by the analytic hierarchy process [J]. Journal of Cleaner Production, 2021, 283: 124659

[29] Kaya M. Recycling Technologies for Secondary Zn-Pb Resources [M], 2023, Cham, Springer International Publishing

[30] Cui J-y, Zhu N-w, Luo D-l, et al.. The role of oxalic acid in the leaching system for recovering indium from waste liquid crystal display panels [J]. ACS Sustainable Chemistry & Engineering, 2019, 7(4): 3849-3857

[31] Yang T-z, Rao S, Zhang D-c, et al.. Leaching of low grade zinc oxide ores in nitrilotriacetic acid solutions [J]. Hydrometallurgy, 2016, 161: 107-111

[32] Jia L-j, Zhong Y-y, Li K, et al.. Recovery of zinc resources from secondary zinc oxide via composite ammonia leaching: Analysis of Zn leaching behavior [J]. Chemical Engineering Journal, 2023, 472: 144930

[33] Yu Y-s, Cui L-x, Zhang L-b, et al.. Improvement of mechanochemical leaching of zinc oxide ore: Optimization of grinding parameters for basket grinder [J]. Journal of Cleaner Production, 2024, 469: 143132

[34] Katsiapi A, Tsakiridis P E, Oustadakis P, et al.. Cobalt recovery from mixed Co–Mn hydroxide precipitates by ammonia–ammonium carbonate leaching [J]. Minerals Engineering, 2010, 23(8): 643-651

[35] Yang S-h, Zhao D-q, Jie Y-f, et al.. Hydrometallurgical process for zinc recovery from C. Z. O. generated by the steelmaking industry with ammonia–ammonium chloride solution [J]. Metals, 2019, 9(1): 83

[36] Yin Z-l, Ding Z-y, Hu H-p, et al.. Dissolution of zinc silicate (hemimorphite) with ammonia–ammonium chloride solution [J]. Hydrometallurgy, 2010, 103(1–4): 215-220

[37] Xue P, Li G-q, Yang Y-x, et al.. Recovery of valuable metals from waste diamond cutters through ammonia–ammonium sulfate leaching [J]. International Journal of Minerals, Metallurgy, and Materials, 2017, 24(12): 1352-1360

[38] Lozano Blanco L J, Meseguer Zapata V F, De Juan García D. Statistical analysis of laboratory results of Zn wastes leaching [J]. Hydrometallurgy, 1999, 54(1): 41-48

[39] Rodriguez Rodriguez N, Gijsemans L, Bussé J, et al.. Selective removal of zinc from BOF sludge by leaching with mixtures of ammonia and ammonium carbonate [J]. Journal of Sustainable Metallurgy, 2020, 6(4): 680-690

[40] Shi G-c, Liao Y-l, Su B-w, et al.. Kinetics of copper extraction from copper smelting slag by pressure oxidative leaching with sulfuric acid [J]. Separation and Purification Technology, 2020, 241: 116699

RIGHTS & PERMISSIONS

Central South University

Just Accepted

This article has successfully passed peer review and final editorial review, and will soon enter typesetting, proofreading and other publishing processes. The currently displayed version is the accepted final manuscript. The officially published version will be updated with format, DOI and citation information upon launch. We recommend that you pay attention to subsequent journal notifications and preferentially cite the officially published version. Thank you for your support and cooperation.