Migration of ammonium nitrogen in ion-absorbed rare earth soils during and post in situ mining: a column study and numerical simulation analysis

Highlights

● Column experiments with an inclined slope were applied to simulate NH₄–N transport.

● The transport of NH₄–N was simulated via HYDRUS-2D.

● The chemical non-equilibrium model well described the transport process.

● The lateral flow led to the preferential loss of surface NH₄–N.

● Flow rate and rainfall intensity affected the adsorption and leaching of NH₄–N.

Abstract

Ion-absorbed rare earth mines, leached in situ, retain a large amount of ammonium nitrogen (NH₄–N) that continuously releases into the surrounding environments. However, quantitative descriptions and predictions of the transport of NH₄–N across mining area with hill slopes are not fully established. Here, laboratory column experiments were designed with an inclined slope (a sand box) to examine the spatial temporal transport of NH₄–N in soils collected from the ionic rare earth elements (REE) mining area. An HYDRUS-2D model simulation of the experimental data over time showed that soils had a strong adsorption capacity toward NH₄–N. Chemical non-equilibrium model (CNEM) could well simulate the transport of NH₄–N through the soil-packed columns. The simulation of the transport-adsorption processes at three flow rates of leaching agents revealed that low flow rate enabled a longer residence time and an increased NH₄-N adsorption, but reduced the extraction efficiency for REE. During the subsequent rainwater washing process, the presence of slope resulted in the leaching of NH₄–N on the surface of the slope, while the leaching of NH₄–N deep inside the column was inhibited. Furthermore, the high-intensity rainfall significantly increased the leaching, highlighting the importance of considering the impact of extreme weather conditions during the leaching process. Overall, our study advances the understanding of the transport of NH₄–N in mining area with hills, the impact of flow rates of leaching agents and precipitation intensities, and presents as a feasible modeling method to evaluate the environmental risks of NH₄–N pollution during and post REE in situ mining activities.

Graphical abstract

Keywords

Ion-absorbed rare earth / Ammonium nitrogen transport / HYDRUS-2D / Numerical simulation

References

[1] Ashraf M S, Izadi B, King B. (1997). Transport of bromide under intermittent and continuous ponding conditions. Journal of Environmental Quality, 26(1): 69–75

[2] Brunetti G, Šimůnek J, Glöckler D, Stumpp C. (2020). Handling model complexity with parsimony: numerical analysis of the nitrogen turnover in a controlled aquifer model setup. Journal of Hydrology (Amsterdam), 584: 124681

[3] Cameron D A, Klute A. (1977). Convective–dispersive solute transport with a combined equilibrium and kinetic adsorption model. Water Resources Research, 13(1): 183–188

[4] Chen Z. (2011). Global rare earth resources and scenarios of future rare earth industry. Journal of Rare Earths, 29(1): 1–6

[5] ChiR A, Tian J (2008). Weathered Crust Elution-Deposited Rare Earth Ores. New York: Nova Science Publishers

[6] Cichota R, Vogeler I, Snow V, Shepherd M, Mcauliffe R, Welten B. (2018). Lateral spread affects nitrogen leaching from urine patches. Science of the Total Environment, 635: 1392–1404

[7] Deng H, Gharasoo M, Zhang L, Dai Z, Hajizadeh A, Peters C A, Soulaine C, Thullner M, Van Cappellen P. (2022). A perspective on applied geochemistry in porous media: reactive transport modeling of geochemical dynamics and the interplay with flow phenomena and physical alteration. Applied Geochemistry, 146: 105445

[8] Doltra J, Muñoz P. (2010). Simulation of nitrogen leaching from a fertigated crop rotation in a Mediterranean climate using the EU-Rotate_N and Hydrus-2D models. Agricultural Water Management, 97(2): 277–285

[9] Dontsova K M, Norton L D, Johnston C T. (2005). Calcium and magnesium effects on ammonia adsorption by soil clays. Soil Science Society of America Journal, 69(4): 1225–1232

[10] Dou X, Shi H, Li R, Miao Q, Yan J, Tian F, Wang B. (2022). Simulation and evaluation of soil water and salt transport under controlled subsurface drainage using HYDRUS-2D model. Agricultural Water Management, 273: 107899

[11] DuX, Graedel T E (2013). Uncovering the end uses of the rare earth elements. Science of the Total Environment, 461–462: 781–784

[12] Golev A, Scott M, Erskine P D, Ali S H, Ballantyne G R. (2014). Rare earths supply chains: current status, constraints and opportunities. Resources Policy, 41: 52–59

[13] GrathwohlP (1998). Diffusion in natural porous media: contaminant transport, sorption/desorption and dissolution kinetics. In: Topics in Environmental Fluid Mechanics 1. Boston: Springer

[14] HansonB R, Šimůnek J, HopmansJ W (2006). Evaluation of urea–ammonium–nitrate fertigation with drip irrigation using numerical modeling. Agricultural Water Management, 86(1–2): 102–113

[15] Hou L, Hu B X, Qi Z, Yang H. (2018). Evaluating equilibrium and non-equilibrium transport of ammonium in a loam soil column. Hydrological Processes, 32(1): 80–92

[16] HouX, XuQ, SunY, WangY, LiJ, ZhouX, LiY (2016). Distribution of residual rare earth and ammonium in the tailing of ion adsorption rare earth deposit after in-situ leaching and the significance. Rare Earths, 37: 1–9 (in Chinese)

[17] Huang X W, Long Z Q, Wang L S, Feng Z Y. (2015). Technology development for rare earth cleaner hydrometallurgy in China. Rare Metals, 34(4): 215–222

[18] JellaliS, Benremita H, MuntzerP, RazakarisoaO, Schäfer G (2003). A large scale experiment on mass transfer of trichloroethylene from the unsaturated zone of a sandy aquifer to its interfaces. Journal of Contaminant Hydrology, 60(1–2): 31–53

[19] Jellali S, Diamantopoulos E, Kallali H, Bennaceur S, Anane M, Jedidi N. (2010). Dynamic sorption of ammonium by sandy soil in fixed bed columns: evaluation of equilibrium and non-equilibrium transport processes. Journal of Environmental Management, 91(4): 897–905

[20] Jing Q X, Chai L Y, Huang X D, Tang C J, Guo H, Wang W. (2017). Behavior of ammonium adsorption by clay mineral halloysite. Transactions of Nonferrous Metals Society of China, 27(7): 1627–1635

[21] KanazawaY, Kamitani M (2006). Rare earth minerals and resources in the world. Journal of Alloys and Compounds, 408–412: 1339–1343

[22] Kheirandish M, An C, Chen Z, Geng X, Boufadel M. (2022). Numerical simulation of benzene transport in shoreline groundwater affected by tides under different conditions. Frontiers of Environmental Science & Engineering, 16(5): 61

[23] Li Y, Šimůnek J, Zhang Z, Jing L, Ni L. (2015). Evaluation of nitrogen balance in a direct-seeded-rice field experiment using Hydrus-1D. Agricultural Water Management, 148: 213–222

[24] Lin Z, Wei G, Zhang J, Liang X, Huang G. (2022). Origin and distribution of rare earth elements (REEs) in the soils of Meizhou City, southern China with high abundance of regolith-hosted REEs. Applied Geochemistry, 147: 105514

[25] Liu H, Zhang D, Li M, Tong L, Feng L. (2013). Competitive adsorption and transport of phthalate esters in the clay layer of Jianghan plain, China. Chemosphere, 92(11): 1542–1549

[26] Mao M, Ren L. (2004). Simulating nonequilibrium transport of atrazine through saturated soil. Ground Water, 42(4): 500–508

[27] Marquardt D W. (1963). An algorithm for least-quares estimation of nonlinear parameters. Journal of the Society for Industrial and Applied Mathematics, 11(2): 431–441

[28] Mo X, Peng H, Xin J, Wang S. (2022). Analysis of urea nitrogen leaching under high-intensity rainfall using HYDRUS-1D. Journal of Environmental Management, 312: 114900

[29] MoradiA, Abbaspour K C, AfyuniM (2005). Modelling field-scale cadmium transport below the root zone of a sewage sludge amended soil in an arid region in Central Iran. Journal of Contaminant Hydrology, 79(3–4): 187–206

[30] Mualem Y. (1976). A new model for predicting the hydraulic conductivity of unsaturated porous media. Water Resources Research, 12(3): 513–522

[31] Ngo V V, Michel J, Gujisaite V, Latifi A, Simonnot M O. (2014). Parameters describing nonequilibrium transport of polycyclic aromatic hydrocarbons through contaminated soil columns: estimability analysis, correlation, and optimization. Journal of Contaminant Hydrology, 158: 93–109

[32] Pernyeszi T, Kasteel R, Witthuhn B, Klahre P, Vereecken H, Klumpp E. (2006). Organoclays for soil remediation: adsorption of 2,4-dichlorophenol on organoclay/aquifer material mixtures studied under static and flow conditions. Applied Clay Science, 32(3–4): 179–189

[33] Šimůnek J, Genuchten M T. (2008). Modeling nonequilibrium flow and transport processes using HYDRUS. Vadose Zone Journal, 7(2): 782–797

[34] Šimůnek J, Genuchten M T, Šejna M. (2016). Recent developments and applications of the HYDRUS computer software packages. Vadose Zone Journal, 15(7): 1–25

[35] ŠimůnekJ, SejnaM, SaitoH, SakaiM, van Genuchten M T H (2013). The HYDRUS-1D software package for simulating the movement of water, heat, and multiple solutes in variably saturated media, version 4.17, HYDRUS software series 3. Riverside: University of California Riverside

[36] ŠimůnekJ, ŠejnaM, van Genuchten M T (2008). The HYDRUS-1D software package for simulating the one-dimensional movement of water, heat, and multiple solutes in variably-saturated media. In: Version 4.0. HYDRUS

[37] ŠimůnekJ, van GenuchtenM T, Šejna M (2011). The HYDRUS software package for simulatingtwo- and three-dimensional movement of water, heat, and multiple solutes in variably-saturatedmedia. Technical Manual, Version 2.0, PC Progress, Prague, Czech Republic

[38] SuarezFBachmann JMunozJ FOrtizCTylerS W AlisterCKogan M (2007). Transport of simazine in unsaturated sandy soil and predictions of its leaching under hypothetical field conditions. Journal of Contaminant Hydrology, 94(3–4): 166–177

[39] Song K, Zhu S, Lu Y, Dao G, Wu Y, Chen Z, Wang S, Liu J, Zhou W, Hu H Y. (2022). Modelling the thresholds of nitrogen/phosphorus concentration and hydraulic retention time for bloom control in reclaimed water landscape. Frontiers of Environmental Science & Engineering, 16(10): 129

[40] Tang J, Qiao J, Xue Q, Liu F, Chen H, Zhang G. (2018). Leach of the weathering crust elution-deposited rare earth ore for low environmental pollution with a combination of (NH₄)₂SO₄ and EDTA. Chemosphere, 199: 160–167

[41] Tian J, Chi R A, Yin J Q. (2010). Leaching process of rare earths from weathered crust elution-deposited rare earth ore. Transactions of Nonferrous Metals Society of China, 20(5): 892–896

[42] van Genuchten M T. (1980). A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Science Society of America Journal, 44(5): 892–898

[43] van GenuchtenM T, ClearlyR W (1979). Movement of solutes in soil: computer simulated and laboratory results. In: Bolt G H, ed. Soil Chemistry B. Physico-chemical Models. The Netherlands: Elsevier Scientific Publ., 349–386

[44] van Genuchten M T, Wagenet R J. (1989). Two-site/two-region models for pesticide transport and degradation: theoretical development and analytical solutions. Soil Science Society of America Journal, 53(5): 1303–1310

[45] Wang B, Lehmann J, Hanley K, Hestrin R, Enders A. (2015). Adsorption and desorption of ammonium by maple wood biochar as a function of oxidation and pH. Chemosphere, 138: 120–126

[46] Xiao Y F, Chen Y Y, Feng Z Y, Huang X W, Huang L, Long Z Q, Cui D L. (2015). Leaching characteristics of ion-adsorption type rare earths ore with magnesium sulfate. Transactions of Nonferrous Metals Society of China, 25(11): 3784–3790

[47] Yang S, Xue Q, Chen H. (2016). Enhanced recovery of water due to ammonia nitrogen contamination caused by mining processes. Environmental Earth Sciences, 75: 1102

[48] Yang X, Xi G, Yao N, Zhou M, Gao X, Chen M, Wang X, Pan Z, Wang Z. (2022). Spatiotemporal distribution of residual ammonium in a rare-earth mine after in-situ leaching: a modeling study with scarce data. Journal of Hydrology (Amsterdam), 615: 128669

[49] Zhou Z, Lin C, Li S, Liu S, Li F, Yuan B. (2021). Four kinds of capping materials for controlling phosphorus and nitrogen release from contaminated sediment using a static simulation experiment. Frontiers of Environmental Science & Engineering, 16(3): 29

Acknowledgements

The authors gratefully acknowledge the Financial of National Key Research and Development Project of China (No. 2019YFC1805102). Partial supports are from the National Natural Science Foundation of China (Nos. 42107228 and 41977266) and Shanghai Pujiang Program (No. 21PJ1401000). Comments from editors and two anonymous reviewers improved the clarify and quality of manuscript.

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