Applied Geochemistry最新文献

{"title":"Geochemical survey of uranium in catchment sediments and prediction of mineralization prospects along the Sino-Mongolian border region","authors":"Lanshi Nie ,&nbsp;Hanliang Liu ,&nbsp;Xueqiu Wang ,&nbsp;Yuntao Song ,&nbsp;Shojin Davaa ,&nbsp;Qinghua Chi ,&nbsp;Dongsheng Liu ,&nbsp;Xinbin Cheng ,&nbsp;Wei Wang","doi":"10.1016/j.apgeochem.2025.106587","DOIUrl":"10.1016/j.apgeochem.2025.106587","url":null,"abstract":"<div><div>The Sino-Mongolian border region, which is located on the Mongolian Plateau in the interior of Asia, is a significant metallogenic belt and one of three major porphyry copper, gold, and molybdenum metallogenic belts on the globe. Although Mongolia and China are rich in uranium resources, there is a lack of in-depth research on the overall spatial distribution characteristics, influencing factors, and prospecting areas of single-element uranium in the Sino-Mongolian border area, particularly in this region. This study addresses this research gap by determining the distribution characteristics and metallogenic potential of uranium resources in the region through 1:1,000,000 geochemical mapping. To achieve this goal, 10,453 catchment sediment samples were systematically collected and analyzed geochemically. These analyses clarified the distribution characteristics of uranium in the region and explored its enrichment mechanisms. Results revealed a wide range of uranium concentrations in the samples, from 0.07 to 335.52 ppm, with median and mean values of 2.10 and 2.54 ppm, respectively. Using the geochemical block delineation method, 21 high-uranium-content areas (&gt;1000 km²) were identified as geochemical provinces or higher. In addition, nine uranium geochemical blocks were delineated, one of which reached the size of a geochemical domain (&gt;100,000 km²). Furthermore, a comprehensive analysis of the regional geological and tectonic characteristics, mineral combinations, mineralization conditions, and exploitation potential identified five prospective uranium exploration areas with significant potential. Delineating these prospective areas provides a clear direction for future mineral exploration and offers a reliable geochemical basis for the development and utilization of regional mineral resources.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106587"},"PeriodicalIF":3.4,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145248005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Scheelite (CaWO4) leaching in mild conditions via heptatungstate sorption by MgAl– Layered Double Hydroxide","authors":"Farah Ajami,&nbsp;Domitille Giaume,&nbsp;Grégory Lefèvre","doi":"10.1016/j.apgeochem.2025.106588","DOIUrl":"10.1016/j.apgeochem.2025.106588","url":null,"abstract":"<div><div>The possibility of extraction of W(VI) as heptatungstate species (W₇O₂₄⁶⁻) from pure scheelite mineral (CaWO₄) under mild conditions has been evaluated using an inorganic anion exchanger MgAl–Layered double hydroxide (LDH). An optimal pH of 5 was determined for the dissolution/adsorption step while desorption was carried out using a carbonate solution at pH 11. After a leaching time of 24 h with an LDH/scheelite ratio of 1.8, up to 30 % of tungsten has been extracted while scheelite alone is almost insoluble in these conditions. Two sorption mechanisms have been assumed: exchange of heptatungstate ions with carbonate ions of the LDH and precipitation of W(VI) with aluminum cations released from LDH dissolution. Thus, this work provides a proof of concept for the use of LDH in the extraction and recovery of tungsten from scheelite through a low environmental footprint process.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106588"},"PeriodicalIF":3.4,"publicationDate":"2025-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Defining the sources and evolution of nitrate in coal mine rock with stable isotopes of nitrate and ammonium","authors":"M. Jim Hendry,&nbsp;Erin Schmeling","doi":"10.1016/j.apgeochem.2025.106584","DOIUrl":"10.1016/j.apgeochem.2025.106584","url":null,"abstract":"<div><div>Elevated concentrations of nitrate (NO₃ˉ) are present in many surface waters associated with coal mining throughout the world. Its presence is generally attributed to blasting using ANFO (NH₄NO₃ and fuel oil) to access the coal. A recent study conducted by our group shows the nitrification of naturally occurring exchangeable ammonium (NH₄⁺-ex) in waste rock can be a major source of NO₃⁻ compared to contributions from NO₃⁻ and the nitrification of NH₄⁺ originating from blast products. Here we show that neither the concentrations of nitrogen species nor the δ¹⁵N–NO₃⁻ and δ¹⁵N–NH₄⁺ values can be used to differentiate the sources of NO₃⁻. However, the measured δ¹⁸O–NO₃ˉ values of NH₄NO₃ (+24.3 ± 1.7 ‰) and NO₃ˉ produced from nitrification of both sources of NH₄⁺ (−4.7 ‰) under oxic laboratory conditions enabled the distinction between these two sources of NO₃ˉ. Fitting the results of a simple mixing model to the experimental data allowed the concentrations of NO₃ˉ derived from NH₄NO₃ in fresh-blasted mine rock to be estimated. The results of this study show the application of δ¹⁸O–NO₃ˉ is a valuable technique to characterize the source(s) and evolution of NO₃⁻ draining from mine rock piles.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"193 ","pages":"Article 106584"},"PeriodicalIF":3.4,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Arsenic speciation and mobility in gold mining-impacted riverine sediments from the Loddon River catchment in Victoria, Australia","authors":"Francesco Colombi ,&nbsp;Ewen Silvester ,&nbsp;Aleicia Holland ,&nbsp;Darren Baldwin ,&nbsp;Colin MacRae ,&nbsp;Nick Wilson ,&nbsp;Ian Rutherfurd ,&nbsp;James Grove ,&nbsp;Jodi Turnbull ,&nbsp;Mark Macklin ,&nbsp;Peter Davies ,&nbsp;Susan Lawrence","doi":"10.1016/j.apgeochem.2025.106582","DOIUrl":"10.1016/j.apgeochem.2025.106582","url":null,"abstract":"<div><div>The Loddon River floodplains, Victoria, southeast Australia, is contaminated with high levels of As (up to 300 mg kg⁻¹) due to re-deposited mine tailings from historical gold mining (1851–1914). Arsenic concentrations often significantly exceed Australia's sediment guidelines (ISQG-high value of 70 ppm). To determine the potential risk associated with As, this study examined the speciation of As and its mineral phase association in sediments along a 60 km stretch of the river, and investigated how As is released under redox cycling conditions. Sequential extraction procedures (SEP) revealed that As is primarily associated with crystalline Feˡˡˡoxyhydroxides (up to 40 %) and residual phases (up to 70 %). X-ray absorption spectroscopy (XAS) analyses showed that As was predominantly in its pentavalent state, existing mainly as Feˡˡˡoxyhydroxides-sorbed arsenate (Fe–AsO₄), with a small amount (up to 18 %) of reduced arsenopyrite (FeAsS) present upstream reaches of the Loddon River. A column experiment simulating flooding-drying cycles was used to assess As mobility. Under reducing conditions, in the presence of a carbon source, As concentrations in the water increased dramatically, reaching up to 1300 μg L⁻¹, far exceeding the WHO drinking water guideline of 10 μg L⁻¹. Microbially-mediated reductive dissolution of Feˡˡˡoxyhydroxides and reduction of As from As(V) to As(III), which has lower affinity for Feˡˡˡoxyhydroxides, was likely responsible for this As release. These findings highlight the enduring presence of As contamination in floodplains impacted by historical gold mining. Furthermore, this study underlines the potential environmental and health risks posed by As in floodplain sediments, particularly as wetting and drying cycles can increase its mobility. Greater efforts are needed to assess the spatial extent of historical pollution in impacted river catchments and develop comprehensive mitigation strategies to address the widespread contamination of floodplain sediments in affected river systems globally.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"193 ","pages":"Article 106582"},"PeriodicalIF":3.4,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A combined 228Ra/226Ra and 87Sr/86Sr approach to identify the production of out-of-zone formation fluid from Marcellus shale gas wells","authors":"L.J. Molofsky ,&nbsp;M.A. Engle ,&nbsp;T.W. Wagner ,&nbsp;A.S. Wylie ,&nbsp;D.P. Fernandez","doi":"10.1016/j.apgeochem.2025.106570","DOIUrl":"10.1016/j.apgeochem.2025.106570","url":null,"abstract":"<div><div>The Marcellus shale is generally characterized by low to irreducible water saturation, and gas wells in this formation typically produce small volumes of produced water compared to the volume of fracturing fluids injected. However, some Marcellus wells produce larger volumes of high-salinity fluids months or years into production, pointing to the possibility of out-of-zone water production. To identify the origin of these high-salinity fluids, we utilize a combination of ²²⁸Ra/²²⁶Ra activity and ⁸⁷Sr/⁸⁶Sr ratios measured in Marcellus produced water samples. Key findings show that: i) bulk rock Th/U and Rb/Sr mass ratios, in concert with fresh water ⁸⁷Sr/⁸⁶Sr leachates, can be used to develop predicted ²²⁸Ra/²²⁶Ra and ⁸⁷Sr/⁸⁶Sr ratios of pore waters within different formations, ii) the ²²⁸Ra/²²⁶Ra and ⁸⁷Sr/⁸⁶Sr ratios of Marcellus produced water are dominated by the Ra²⁺ and Sr²⁺ content of downhole formation fluids and water-accessible fractions, and iii) Marcellus wells with higher water-to-gas production ratios (e.g. &gt;1 bbl water/10⁶ ft³ gas, or &gt;5.6 m³ water/10⁶ m³ gas) and elevated TDS (&gt;100,000 mg/L) exhibit lower ⁸⁷Sr/⁸⁶Sr ratios, consistent with a significant contribution from exogenous Onondaga pore fluids. The approach developed here has potential utility for identifying out-of-zone water sources in other oil and gas basins.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106570"},"PeriodicalIF":3.4,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145326435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of phase for shale oil and gas using integrated geological-geochemical methods","authors":"Shang Xu ,&nbsp;Yunxuan Guo ,&nbsp;Bingchang Liu ,&nbsp;Haicheng Liu ,&nbsp;Yuliang Zhang ,&nbsp;Dong Yang","doi":"10.1016/j.apgeochem.2025.106581","DOIUrl":"10.1016/j.apgeochem.2025.106581","url":null,"abstract":"<div><div>For shale oil and gas in an advanced stage of thermal maturation, defining the phase evolution and delineating phase boundaries is critical for exploration and development. This study targets the lower submember of the third member of the Shahejie Formation (Es3L) in the Zhanhua Depression, which is situated within the Bohai Bay Basin, East China, integrating detailed geological and geochemical analyses of the target stratum. The shale is dominated by carbonate-clastic mixed facies, characterized by high total organic carbon (TOC) content, dominated by Type II kerogen, strong early oil-generation potential, and significant secondary gas generation from oil cracking at high maturity. By integrating gas logging data and gas-oil ratio (GOR) measurements, two key phase boundaries were identified: approximately 4230 m for the transition from volatile oil to condensate gas, and approximately 4550 m for the transition from condensate gas to wet/dry gas. Phase evolution follows a systematic trend: the volatile oil stage is enriched in C₂-C₅ components, has low GOR, and is oil-phase dominated; the condensate gas stage shows elevated GOR with characteristic oil-gas coexistence; the wet/dry gas stage (Ro &gt; 2.2 %) is methane-dominated with a sharply increasing GOR. Accurate identification of these phase boundaries provides a basis for product-type determination, reservoir stimulation design, and development strategy optimization, and offers transferable implications for phase prediction in shale systems with similar geological settings.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"193 ","pages":"Article 106581"},"PeriodicalIF":3.4,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mercury isotopes from ferromanganese rocks fingerprint metal recycling by intracontinental basinal fluids","authors":"Alexandre Raphael Cabral ,&nbsp;Runsheng Yin ,&nbsp;Di Chen ,&nbsp;Stephanie Lohmeier ,&nbsp;Tiago Henrique DeFerreira ,&nbsp;Francisco Javier Rios ,&nbsp;Bernd Lehmann","doi":"10.1016/j.apgeochem.2025.106583","DOIUrl":"10.1016/j.apgeochem.2025.106583","url":null,"abstract":"<div><div>Mercury isotopes, capable of mass-dependent fractionation (δ²⁰²Hg) and mass-independent fractionation (Δ¹⁹⁹Hg), are particularly useful in tracing ore-forming sources and metallogenic pathways in mineral deposits. Here, we apply Hg isotopes to elucidate the formation of ferromanganese sedimentary rocks in a Cenozoic, graben-like sedimentary basin. The basin was a historically important Mn supplier within the Archaean–Palaeoproterozoic Quadrilátero Ferrífero of Minas Gerais, Brazil. The rocks are enriched in Hg, up to about 9700 ppb, and have negative Δ¹⁹⁹Hg down to −0.39‰. The negative Δ¹⁹⁹Hg signals are consistent with the signature of terrestrial reservoirs, suggesting that the ferromanganese enrichment received Hg from terrestrial sediments, in consonance with the intracontinental setting of the basin. Ferromanganese samples with more than 5% Mn show a positive correlation of Fe/Mn vs. δ²⁰²Hg, which likely represents intracontinental basinal fluids with positive δ²⁰²Hg signals of dissolved Hg(II). Mercury was leached from terrestrial sediments and preferentially sequestered by Fe-oxide precipitates, mostly goethite. The transfer of Hg, traced by its isotopes, to ferromanganese concentrations testifies to metal recycling by Cenozoic basinal fluids within the Archaean–Palaeoproterozoic Quadrilátero Ferrífero.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"194 ","pages":"Article 106583"},"PeriodicalIF":3.4,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geochemical and mineralogical investigations of niobium mine tailings in Québec, Canada","authors":"Birendra Sapkota ,&nbsp;Eleanor J. Berryman ,&nbsp;Nail Zagrtdenov ,&nbsp;Richard R. Goulet","doi":"10.1016/j.apgeochem.2025.106580","DOIUrl":"10.1016/j.apgeochem.2025.106580","url":null,"abstract":"<div><div>Niobium (Nb) has been identified as a critical metal important in the transition to a low-carbon economy. As the global demand for Nb mining increases, it is important to ensure that Nb mine tailings management facilities are designed to limit leaching of potentially toxic elements. In this study, we combine geochemical and mineralogical analyses to identify elements of concern in the tailings from an active Nb mine in Québec, Canada. The major components of the ten tailings samples characterized include CaO (&lt;37.2 wt%), Fe₂O_3(total) (&lt;13.7 wt%), MgO (&lt;12.7 wt%), P₂O₅ (&lt;17.1 wt%), and inorganic carbon (&lt;35.6 wt%). The minor components include Al₂O₃, K₂O, SrO, Nb₂O₅, BaO, and Na₂O, in decreasing order of abundance. Mineralogical observations indicate dolomite (&gt;40 vol%), calcite, apatite, magnetite, and ankerite to be the major (&gt;5 vol%) phases. Nb is primarily hosted by columbite and pyrochlore. Phosphorus (P) is almost entirely hosted by apatite. Lanthanum (La), cerium (Ce), and neodymium (Nd) are also hosted primarily by apatite and to a lesser extent by parisite. The sequential extraction data are generally consistent with their expected mineral-hosts determined by element deportment calculations. Niobium remains in the residual fraction and is considered environmentally immobile. Apatite-hosted elements (mainly P, and lesser amounts of Ce, La, and Nd) are mobilized by the modified aqua regia leach step, reflecting dissolution of apatite under acidic conditions. Of note is a small proportion of Ce (&lt;1 %) associated with weak acid soluble/carbonate fraction. Additionally, aluminum (Al) is an important element of the tailings (up to 0.9 wt%). Acidification and alkalinization of the tailings, along with the presence of complexing ligands, such as F and dissolved organic carbon, could increase Al mobility, leading to its potential toxicity to aquatic organisms. Therefore, we recommend that the design of Nb tailings management facilities is guided by an inventory of Al, P, Ce, La and Nd and their release rates, with these data iteratively applied in risk assessment models. The goal is to achieve predicted impacts consistent with water quality guidelines for the protection of aquatic life, or, if not possible, to reach concentrations that are as low as reasonably achievable.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"193 ","pages":"Article 106580"},"PeriodicalIF":3.4,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sorption of Eu(III) on C–S–H phases in the presence of gluconate: A molecular dynamics study","authors":"Iuliia Androniuk,&nbsp;Rosa Ester Guidone,&nbsp;Marcus Altmaier,&nbsp;Xavier Gaona","doi":"10.1016/j.apgeochem.2025.106579","DOIUrl":"10.1016/j.apgeochem.2025.106579","url":null,"abstract":"<div><div>Cement is a key barrier material in radioactive waste repositories, where calcium-silicate-hydrate (C–S–H) phases play a central role in immobilizing cationic radionuclides. However, organic ligands, originating from additives or waste, can enhance radionuclide mobility by forming soluble complexes and competing for surface sorption. In this study, a surface model was developed that combines experimental observations with theoretical insights into C–S–H structure, enabling detailed sampling of the most probable sorption sites. Molecular dynamics (MD) simulations and potential of mean force (PMF) calculations were used to develop molecular-scale understanding of how organic additives influence the adsorption and mobility of trivalent actinides and lanthanides in cementitious materials. Eu(III) was considered as a model of key trivalent radionuclides expected in nuclear waste, <em>i.e.</em> Pu(III) and Am(III), based on their similar charge-to-size (<em>z</em>/<em>d</em>) ratios, and gluconate was chosen as a model organic ligand. The results from the Eu(III)/C–S–H binary system confirmed strong sorption and showed that the most common sorption sites are the deprotonated silanol groups of the surface. Results obtained for the binary system are in line with Time Resolved Laser Fluorescence Spectroscopy data available for Eu(III) and Cm(III). Depending on gluconate concentration, two main effects on Eu(III) uptake on the C–S–H phases have been found: (a) sorption of the 1:1 Eu(III)-GLU complex at low ligand concentration; (b) formation of a stable ternary Ca–Eu(III)-GLU aqueous complex that does not sorb at high ligand concentration. It is important to consider formation of the ternary complex C–S–H/Eu(III)/GLU for the overall interpretation and understanding of the system.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"193 ","pages":"Article 106579"},"PeriodicalIF":3.4,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterisation, concentration and acidic reductive leaching of limonitic laterites from New Caledonia","authors":"Agathe Hubau ,&nbsp;Agnieszka Dybowska ,&nbsp;Paul F. Schofield ,&nbsp;Diego Gianolio ,&nbsp;Ana Santos ,&nbsp;Richard J. Herrington ,&nbsp;Douglas Pino-Herrera ,&nbsp;Hafida Tris ,&nbsp;Marion Erard ,&nbsp;Anne-Gwénaëlle Guezennec","doi":"10.1016/j.apgeochem.2025.106569","DOIUrl":"10.1016/j.apgeochem.2025.106569","url":null,"abstract":"<div><div>This study aimed at determining Ni and Co leaching kinetics from a New Caledonian laterite in an acidic medium (H₂SO₄ pH 1.5) and in a reductive environment (addition of SO₃²⁻ or Fe(II)) at 46 °C. The mineralogical study revealed that Co was mainly carried by Mn oxyhydroxides in the limonite sample. Conversely, Ni was hosted by both Fe and Mn oxyhydroxides. In the presence of a reductive reagent, Mn oxyhydroxides dissolved rapidly compared to goethite, the main Fe oxyhydroxide in the sample. Co, Mn and Ni reductive leaching yields reached 79 %, 83 % and 9 % respectively after 2 days. Based on these results, a Mn oxides concentrate was produced in order to efficiently leach Co while limiting Fe oxyhydroxide dissolution. This concentrate resulted from a combination of particle size and gravity separation steps. The volume/mass of sample was drastically decreased since the mass of the final sample was only 3.3 % of the initial one. Co content increased from 0.16 wt% in the limonite to 2.3 wt% in the concentrate, representing an enrichment factor of 13.8 and recovery yield of 60 %. Co, Mn and Ni leaching yields reached 87 %, 95 % and 80 % respectively in the Mn oxides concentrate leaching experiment. The difference in Ni behaviour was consistent with the mineralogical composition: Ni was mainly carried by the goethite in the laterite, while it was hosted mainly by the Mn oxyhydroxides in the Mn oxides concentrate. This study gives a proof of concept for the development a robust pre-concentration process to recover Co.</div></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"193 ","pages":"Article 106569"},"PeriodicalIF":3.4,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}