Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Search Results (696)

Search Parameters:
Keywords = magnetic mineral

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
16 pages, 4205 KiB  
Article
Coarse and Fine-Grained Sediment Magnetic Properties from Upstream to Downstream in Jiulong River, Southeastern China and Their Environmental Implications
by Rou Wen, Shengqiang Liang, Mingkun Li, Marcos A. E. Chaparro and Yajuan Yuan
J. Mar. Sci. Eng. 2025, 13(8), 1502; https://doi.org/10.3390/jmse13081502 - 5 Aug 2025
Viewed by 1
Abstract
Magnetic parameters of river sediments are commonly used as end-members for source tracing in the coasts and shelves. The eastern continental shelf area of China, with multiple sources of input, is a key region for discussing sediment sources. However, magnetic parameters are influenced [...] Read more.
Magnetic parameters of river sediments are commonly used as end-members for source tracing in the coasts and shelves. The eastern continental shelf area of China, with multiple sources of input, is a key region for discussing sediment sources. However, magnetic parameters are influenced by grain size, and the nature of this influence remains unclear. In this study, the Jiulong River was selected as a case to analyze the magnetic parameters and mineral characteristics for both the coarse (>63 μm) and fine-grained (<63 μm) fractions. Results show that the magnetic minerals mainly contain detrital-sourced magnetite and hematite. In the North River, a tributary of the Jiulong River, the content of coarse-grained magnetic minerals increases from upstream to downstream, contrary to fine-grained magnetic minerals, suggesting the influence of hydrodynamic forces. Some samples with abnormally high magnetic susceptibility may result from the combined influence of the parent rock and human activities. In the scatter diagrams of magnetic parameters for provenance tracing, samples of the <63 μm fractions have a more concentrated distribution than that of the >63 μm fractions. Hence, magnetic parameters for the <63 μm fraction are more useful in provenance identification. Full article
(This article belongs to the Section Marine Environmental Science)
Show Figures

Figure 1

24 pages, 6356 KiB  
Article
Tectonic Rift-Related Manganese Mineralization System and Its Geophysical Signature in the Nanpanjiang Basin
by Daman Cui, Zhifang Zhao, Wenlong Liu, Haiying Yang, Yun Liu, Jianliang Liu and Baowen Shi
Remote Sens. 2025, 17(15), 2702; https://doi.org/10.3390/rs17152702 - 4 Aug 2025
Viewed by 226
Abstract
The southeastern Yunnan region in the southwestern Nanpanjiang Basin is one of the most important manganese enrichment zones in China. Manganese mineralization is mainly confined to marine mud–sand–carbonate interbeds of the Middle Triassic Ladinian Falang Formation (T2f), which contains several [...] Read more.
The southeastern Yunnan region in the southwestern Nanpanjiang Basin is one of the most important manganese enrichment zones in China. Manganese mineralization is mainly confined to marine mud–sand–carbonate interbeds of the Middle Triassic Ladinian Falang Formation (T2f), which contains several medium to large deposits such as Dounan, Baixian, and Yanzijiao. However, the geological processes that control manganese mineralization in this region remain insufficiently understood. Understanding the tectonic evolution of the basin is therefore essential to unravel the mechanisms of Middle Triassic metallogenesis. This study investigates how rift-related tectonic activity influences manganese ore formation. This study integrates global gravity and magnetic field models (WGM2012, EMAG2v3), audio-frequency magnetotelluric (AMT) profiles, and regional geological data to investigate ore-controlling structures. A distinct gravity low–magnetic high belt is delineated along the basin axis, indicating lithospheric thinning and enhanced mantle-derived heat flow. Structural interpretation reveals a rift system with a checkerboard pattern formed by intersecting NE-trending major faults and NW-trending secondary faults. Four hydrothermal plume centers are identified at these fault intersections. AMT profiles show that manganese ore bodies correspond to stable low-resistivity zones, suggesting fluid-rich, hydrothermally altered horizons. These findings demonstrate a strong spatial coupling between hydrothermal activity and mineralization. This study provides the first identification of the internal rift architecture within the Nanpanjiang Basin. The basin-scale rift–graben system exerts first-order control on sedimentation and manganese metallogenesis, supporting a trinity model of tectonic control, hydrothermal fluid transport, and sedimentary enrichment. These insights not only improve our understanding of rift-related manganese formation in southeastern Yunnan but also offer a methodological framework applicable to similar rift basins worldwide. Full article
Show Figures

Figure 1

20 pages, 4663 KiB  
Article
Investigation on Imbibition Recovery Characteristics in Jimusar Shale Oil and White Mineral Oil by NMR
by Dunqing Liu, Chengzhi Jia and Keji Chen
Energies 2025, 18(15), 4111; https://doi.org/10.3390/en18154111 - 2 Aug 2025
Viewed by 185
Abstract
Recovering oil by fracturing fluid imbibition has demonstrated significant potential for enhanced oil recovery (EOR) in tight oil reservoirs. White mineral oil (WMO), kerosene, or saturated alkanes with matched apparent viscosity have been widely used as “crude oil” to investigate imbibition mechanisms in [...] Read more.
Recovering oil by fracturing fluid imbibition has demonstrated significant potential for enhanced oil recovery (EOR) in tight oil reservoirs. White mineral oil (WMO), kerosene, or saturated alkanes with matched apparent viscosity have been widely used as “crude oil” to investigate imbibition mechanisms in light shale oil or tight oil. However, the representativeness of these simulated oils for low-maturity crude oils with higher viscosity and greater content of resins and asphaltenes requires further research. In this study, imbibition experiments were conducted and T2 and T1T2 nuclear magnetic resonance (NMR) spectra were adopted to investigate the oil recovery characteristics among resin–asphaltene-rich Jimusar shale oil and two WMOs. The overall imbibition recovery rates, pore scale recovery characteristics, mobility variations among oils with different occurrence states, as well as key factors influencing imbibition efficiency were analyzed. The results show the following: (1) WMO, kerosene, or alkanes with matched apparent viscosity may not comprehensively replicate the imbibition behavior of resin–asphaltene-rich crude oils. These simplified systems fail to capture the pore-scale occurrence characteristics of resins/asphaltenes, their influence on pore wettability alteration, and may consequently overestimate the intrinsic imbibition displacement efficiency in reservoir formations. (2) Surfactant optimization must holistically address the intrinsic coupling between interfacial tension reduction, wettability modification, and pore-scale crude oil mobilization mechanisms. The alteration of overall wettability exhibits higher priority over interfacial tension in governing displacement dynamics. (3) Imbibition displacement exhibits selective mobilization characteristics for oil phases in pores. Specifically, when the oil phase contains complex hydrocarbon components, lighter fractions in larger pores are preferentially mobilized; when the oil composition is homogeneous, oil in smaller pores is mobilized first. Full article
(This article belongs to the Special Issue New Progress in Unconventional Oil and Gas Development: 2nd Edition)
Show Figures

Figure 1

21 pages, 1458 KiB  
Article
Production of a Biosurfactant for Application in the Cosmetics Industry
by Ana Paula Barbosa Cavalcanti, Gleice Paula de Araújo, Káren Gercyane de Oliveira Bezerra, Fabíola Carolina Gomes de Almeida, Maria da Glória Conceição da Silva, Alessandra Sarubbo, Cláudio José Galdino da Silva Júnior, Rita de Cássia Freire Soares da Silva and Leonie Asfora Sarubbo
Fermentation 2025, 11(8), 451; https://doi.org/10.3390/fermentation11080451 - 2 Aug 2025
Viewed by 329
Abstract
The cosmetics industry has been seeking to develop products with renewable natural ingredients to reduce the use of or even replace synthetic substances. Biosurfactants can help meet this demand. These natural compounds are renewable, biodegradable, and non-toxic or have low toxicity, offering minimal [...] Read more.
The cosmetics industry has been seeking to develop products with renewable natural ingredients to reduce the use of or even replace synthetic substances. Biosurfactants can help meet this demand. These natural compounds are renewable, biodegradable, and non-toxic or have low toxicity, offering minimal risk to humans and the environment, which has attracted the interest of an emerging consumer market and, consequently, the cosmetics industry. The aim of the present study was to produce a biosurfactant from the yeast Starmerella bombicola ATCC 22214 cultivated in a mineral medium containing 10% soybean oil and 5% glucose. The biosurfactant reduced the surface tension of water from 72.0 ± 0.1 mN/m to 33.0 ± 0.3 mN/m after eight days of fermentation. The yield was 53.35 ± 0.39 g/L and the critical micelle concentration was 1000 mg/L. The biosurfactant proved to be a good emulsifier of oils used in cosmetic formulations, with emulsification indices ranging from 45.90 ± 1.69% to 68.50 ± 1.10%. The hydrophilic–lipophilic balance index demonstrated the wetting capacity of the biosurfactant and its tendency to form oil-in-water (O/W) emulsions, with 50.0 ± 0.20% foaming capacity. The biosurfactant did not exhibit cytotoxicity in the MTT assay or irritant potential. Additionally, an antioxidant activity of 58.25 ± 0.32% was observed at a concentration of 40 mg/mL. The compound also exhibited antimicrobial activity against various pathogenic microorganisms. The characterisation of the biosurfactant using magnetic nuclear resonance and Fourier transform infrared spectroscopy revealed that the biomolecule is a glycolipid with an anionic nature. The results demonstrate that biosurfactant produced in this work has potential as an active biotechnological ingredient for innovative, eco-friendly cosmetic formulations. Full article
(This article belongs to the Special Issue The Industrial Feasibility of Biosurfactants)
Show Figures

Figure 1

17 pages, 3206 KiB  
Article
Inverse Punicines: Isomers of Punicine and Their Application in LiAlO2, Melilite and CaSiO3 Separation
by Maximilian H. Fischer, Ali Zgheib, Iliass El Hraoui, Alena Schnickmann, Thomas Schirmer, Gunnar Jeschke and Andreas Schmidt
Separations 2025, 12(8), 202; https://doi.org/10.3390/separations12080202 - 30 Jul 2025
Viewed by 159
Abstract
The transition to sustainable energy systems demands efficient recycling methods for critical raw materials like lithium. In this study, we present a new class of pH- and light-switchable flotation collectors based on isomeric derivatives of the natural product Punicine, termed inverse Punicines. [...] Read more.
The transition to sustainable energy systems demands efficient recycling methods for critical raw materials like lithium. In this study, we present a new class of pH- and light-switchable flotation collectors based on isomeric derivatives of the natural product Punicine, termed inverse Punicines. These amphoteric molecules were synthesized via a straightforward four-step route and structurally tuned for hydrophobization by alkylation. Their performance as collectors was evaluated in microflotation experiments of lithium aluminate (LiAlO2) and silicate matrix minerals such as melilite and calcium silicate. Characterization techniques including ultraviolet-visible (UV-Vis), nuclear magnetic resonance (NMR) and electron spin resonance (ESR) spectroscopy as well as contact angle, zeta potential (ζ potential) and microflotation experiments revealed strong pH- and structure-dependent interactions with mineral surfaces. Notably, N-alkylated inverse Punicine derivatives showed high flotation yields for LiAlO2 at pH of 11, with a derivative possessing a dodecyl group attached to the nitrogen as collector achieving up to 86% recovery (collector conc. 0.06 mmol/L). Preliminary separation tests showed Li upgrading from 5.27% to 6.95%. Radical formation and light-response behavior were confirmed by ESR and flotation tests under different illumination conditions. These results demonstrate the potential of inverse Punicines as tunable, sustainable flotation reagents for advanced lithium recycling from complex slag systems. Full article
(This article belongs to the Special Issue Application of Green Flotation Technology in Mineral Processing)
Show Figures

Graphical abstract

31 pages, 10410 KiB  
Article
Integrated Prospectivity Mapping for Copper Mineralization in the Koldar Massif, Kazakhstan
by Dinara Talgarbayeva, Andrey Vilayev, Elmira Serikbayeva, Elmira Orynbassarova, Hemayatullah Ahmadi, Zhanibek Saurykov, Nurmakhambet Sydyk, Aigerim Bermukhanova and Berik Iskakov
Minerals 2025, 15(8), 805; https://doi.org/10.3390/min15080805 - 30 Jul 2025
Viewed by 403
Abstract
This study developed a copper mineral prospectivity map for the Koldar massif, Kazakhstan, using an integrated approach combining geophysical and satellite methods. A strong spatialgenetic link was identified between faults and hydrothermal mineralization, with faults acting as key conduits for ore-bearing fluids. Lineament [...] Read more.
This study developed a copper mineral prospectivity map for the Koldar massif, Kazakhstan, using an integrated approach combining geophysical and satellite methods. A strong spatialgenetic link was identified between faults and hydrothermal mineralization, with faults acting as key conduits for ore-bearing fluids. Lineament analysis and density mapping confirmed the high permeability of the Koldar massif, indicating its structural prospectivity. Hyperspectral and multispectral data (ASTER, PRISMA, WorldView-3) were applied for detailed mapping of hydrothermal alteration (phyllic, propylitic, argillic zones), which are critical for discovering porphyry copper deposits. In particular, WorldView-3 imagery facilitated the identification of new prospective zones. The transformation of magnetic and gravity data successfully delineated geological features and structural boundaries, confirming the fractured nature of the massif, a key structural factor for mineralization. The resulting map of prospective zones, created by normalizing and integrating four evidential layers (lineament density, PRISMA-derived hydrothermal alteration, magnetic, and gravity anomalies), is thoroughly validated, successfully outlining the known Aktogay, Aidarly, and Kyzylkiya deposits. Furthermore, new, previously underestimated prospective areas were identified. This work fills a significant knowledge gap concerning the Koldar massif, which had not been extensively studied using satellite methods previously. The key advantage of this research lies in its comprehensive approach and the successful application of high-quality hyperspectral imagery for mapping new prospective zones, offering a cost-effective and efficient alternative to traditional ground-based investigations. Full article
(This article belongs to the Section Mineral Exploration Methods and Applications)
Show Figures

Figure 1

20 pages, 6964 KiB  
Article
Mineralogical Analysis of Factors Affecting the Grade of High-Gradient Magnetic Separation Concentrates and Experimental Study on TiO2 Enrichment Using ARC
by Yifei Liu, Zhenqiang Liu, Yuhua Wang, Yuxin Zhang and Dongfang Lu
Minerals 2025, 15(8), 799; https://doi.org/10.3390/min15080799 - 30 Jul 2025
Viewed by 218
Abstract
High-gradient magnetic separation is a key step in the pre-concentration of ilmenite before flotation, particularly in the gravity separation process. However, as the amount of weakly magnetic gangue minerals increases, the grade of the coarse concentrate from high-gradient magnetic separation decreases. This paper [...] Read more.
High-gradient magnetic separation is a key step in the pre-concentration of ilmenite before flotation, particularly in the gravity separation process. However, as the amount of weakly magnetic gangue minerals increases, the grade of the coarse concentrate from high-gradient magnetic separation decreases. This paper investigates the mineralogical factors affecting the enrichment efficiency of high-gradient magnetic separation. Additionally, a newly developed stirred fluidized bed device, an agitated reflux classifier (ARC), was successfully applied to remove weakly magnetic gangue minerals that are difficult to separate by high-gradient magnetic separation (HGMS). For low-grade ilmenite with a feed grade of 3.97%, a combined process of magnetic separation and gravity separation was employed, achieving a concentrate with a grade of 16.50% and a recovery rate of 54.11%. This concentrate meets the requirements for flotation feed. This study provides a new approach for the beneficiation of low-grade ilmenite. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
Show Figures

Figure 1

9 pages, 3420 KiB  
Article
Using Geophysical Techniques to Ameliorate Dyke Related Issues When Mining for Platinum in South Africa
by Gordon R. J. Cooper
Minerals 2025, 15(8), 793; https://doi.org/10.3390/min15080793 - 29 Jul 2025
Viewed by 134
Abstract
The mining of essential minerals is often made more difficult by subsurface geological structures such as dykes and contacts. The a priori knowledge of these features can greatly mitigate the problems that they would otherwise cause. For that reason, techniques such as geophysics [...] Read more.
The mining of essential minerals is often made more difficult by subsurface geological structures such as dykes and contacts. The a priori knowledge of these features can greatly mitigate the problems that they would otherwise cause. For that reason, techniques such as geophysics and drilling are used to plan the mining in detail. This manuscript introduces a new technique which allows for the interpretation of aeromagnetic data without any knowledge of the source of the magnetic anomalies. In addition, the method is stable and does not rely on higher-order derivatives of the data, unlike many other approaches. Platinum mining is extremely important in South Africa, providing much-needed employment and bringing funds to the economy as a whole. The proposed method is demonstrated using data from the Eastern Bushveld complex, where platinum mining is widespread. Full article
(This article belongs to the Section Mineral Exploration Methods and Applications)
Show Figures

Figure 1

15 pages, 2134 KiB  
Article
Integrated Characterization of Sediments Contaminated by Acid Mine Drainage: Mineralogical, Magnetic, and Geochemical Properties
by Patrícia Gomes, Teresa Valente and Eric Font
Minerals 2025, 15(8), 786; https://doi.org/10.3390/min15080786 - 26 Jul 2025
Viewed by 245
Abstract
Acid mine drainage, a consequence of exposure of sulfide mining waste to weathering processes, results in significant water, sediment, and soil contamination. This contamination results in acidophilic ecosystems, with low pH values and elevated concentrations of sulfate and potentially toxic elements. The São [...] Read more.
Acid mine drainage, a consequence of exposure of sulfide mining waste to weathering processes, results in significant water, sediment, and soil contamination. This contamination results in acidophilic ecosystems, with low pH values and elevated concentrations of sulfate and potentially toxic elements. The São Domingos mine, an abandoned site in the Iberian Pyrite Belt, lacks remediation measures and has numerous waste dumps, which are a major source of contamination to local water systems. Therefore, this study examines sediment accumulation in five mine dams along the São Domingos stream that traverses the entire mine complex. Decades of sediment and waste transport since mine closure have resulted in dam-clogging processes. The geochemical, mineralogical, and magnetic properties of the sediments were analyzed to evaluate the mineralogical controls on the mobilization of potentially toxic elements. The sediments are dominated by iron oxides, oxyhydroxides, and hydroxysulfates, with jarosite playing a key role in binding high concentrations of iron and toxic elements. However, no considerable correlation was found between potentially toxic elements and magnetic parameters, highlighting the complex behavior of these contaminants in acid mine drainage-affected systems. Full article
(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
Show Figures

Figure 1

17 pages, 2629 KiB  
Article
Recovery of High-Alkali-Grade Feldspar Substitute from Phonolite Tailings
by Savas Ozun, Semsettin Ulutas and Sema Yurdakul
Processes 2025, 13(8), 2334; https://doi.org/10.3390/pr13082334 - 23 Jul 2025
Viewed by 281
Abstract
Phonolite is a fine-grained, shallow extrusive rock rich in alkali minerals and containing iron/titanium-bearing minerals. This rock is widely used as a construction material for building exteriors due to its excellent abrasion resistance and insulation properties. However, during the cutting process, approximately 70% [...] Read more.
Phonolite is a fine-grained, shallow extrusive rock rich in alkali minerals and containing iron/titanium-bearing minerals. This rock is widely used as a construction material for building exteriors due to its excellent abrasion resistance and insulation properties. However, during the cutting process, approximately 70% of the rock is discarded as tailing. So, this study aims to repurpose tailings from a phonolite cutting and sizing plant into a high-alkali ceramic raw mineral concentrate. To enable the use of phonolite tailings in ceramic manufacturing, it is necessary to remove coloring iron/titanium-bearing minerals, which negatively affect the final product. To achieve this removal, dry/wet magnetic separation processes, along with flotation, were employed both individually and in combination. The results demonstrated that using dry high-intensity magnetic separation (DHIMS) resulted in a concentrate with an Fe2O3 + TiO2 grade of 0.95% and a removal efficiency of 85%. The wet high-intensity magnetic separation (WHIMS) process reduced the Fe2O3 + TiO2 grade of the concentrate to 1.2%, with 70% removal efficiency. During flotation tests, both pH levels and collector concentration impacted the efficiency and Fe2O3 + TiO2 grade (%) of the concentrate. The lowest Fe2O3 + TiO2 grade of 1.65% was achieved at a pH level of 10 with a collector concentration of 2000 g/t. Flotation concentrates processed with DHIMS achieved a minimum Fe2O3 + TiO2 grade of 0.90%, while those processed with WHIMS exhibited higher Fe2O3 + TiO2 grades (>1.1%) and higher recovery rates (80%). Additionally, studies on flotation applied to WHIMS concentrates showed that collector concentration, pulp density, and conditioning time significantly influenced the Fe2O3 + TiO2 grade of the final concentrate. Full article
(This article belongs to the Section Separation Processes)
Show Figures

Figure 1

26 pages, 9458 KiB  
Article
Wettability Characteristics of Mixed Sedimentary Shale Reservoirs in Saline Lacustrine Basins and Their Impacts on Shale Oil Energy Replenishment: Insights from Alternating Imbibition Experiments
by Lei Bai, Shenglai Yang, Dianshi Xiao, Hongyu Wang, Jian Wang, Jin Liu and Zhuo Li
Energies 2025, 18(14), 3887; https://doi.org/10.3390/en18143887 - 21 Jul 2025
Viewed by 336
Abstract
Due to the complex mineral composition, low clay content, and strong heterogeneity of the mixed sedimentary shale in the Xinjiang Salt Lake Basin, the wettability characteristics of the reservoir and their influencing factors are not yet clear, which restricts the evaluation of oil-bearing [...] Read more.
Due to the complex mineral composition, low clay content, and strong heterogeneity of the mixed sedimentary shale in the Xinjiang Salt Lake Basin, the wettability characteristics of the reservoir and their influencing factors are not yet clear, which restricts the evaluation of oil-bearing properties and the identification of sweet spots. This paper analyzed mixed sedimentary shale samples from the Lucaogou Formation of the Jimsar Sag and the Fengcheng Formation of the Mahu Sag. Methods such as petrographic thin sections, X-ray diffraction, organic matter content analysis, and argon ion polishing scanning electron microscopy were used to examine the lithological and mineralogical characteristics, geochemical characteristics, and pore space characteristics of the mixed sedimentary shale reservoir. Alternating imbibition and nuclear magnetic resonance were employed to quantitatively characterize the wettability of the reservoir and to discuss the effects of compositional factors, lamina types, and pore structure on wettability. Research findings indicate that the total porosity, measured by the alternate imbibition method, reached 72% of the core porosity volume, confirming the effectiveness of alternate imbibition in filling open pores. The Lucaogou Formation exhibits moderate to strong oil-wet wettability, with oil-wet pores predominating and well-developed storage spaces; the Fengcheng Formation has a wide range of wettability, with a higher proportion of mixed-wet pores, strong heterogeneity, and weaker oil-wet properties compared to the Lucaogou Formation. TOC content has a two-segment relationship with wettability, where oil-wet properties increase with TOC content at low TOC levels, while at high TOC levels, the influence of minerals such as carbonates dominates; carbonate content shows an “L” type response to wettability, enhancing oil-wet properties at low levels (<20%), but reducing it due to the continuous weakening effect of minerals when excessive. Lamina types in the Fengcheng Formation significantly affect wettability differentiation, with carbonate-shale laminae dominating oil pores, siliceous laminae contributing to water pores, and carbonate–feldspathic laminae forming mixed pores; the Lucaogou Formation lacks significant laminae, and wettability is controlled by the synergistic effects of minerals, organic matter, and pore structure. Increased porosity strengthens oil-wet properties, with micropores promoting oil adsorption through their high specific surface area, while macropores dominate in terms of storage capacity. Wettability is the result of the synergistic effects of multiple factors, including TOC, minerals, lamina types, and pore structure. Based on the characteristic that oil-wet pores account for up to 74% in shale reservoirs (mixed-wet 12%, water-wet 14%), a wettability-targeted regulation strategy is implemented during actual shale development. Surfactants are used to modify oil-wet pores, while the natural state of water-wet and mixed-wet pores is maintained to avoid interference and preserve spontaneous imbibition advantages. The soaking period is thus compressed from 30 days to 3–5 days, thereby enhancing matrix displacement efficiency. Full article
(This article belongs to the Special Issue Sustainable Development of Unconventional Geo-Energy)
Show Figures

Figure 1

23 pages, 6480 KiB  
Article
Mechanism Analysis and Evaluation of Formation Physical Property Damage in CO2 Flooding in Tight Sandstone Reservoirs of Ordos Basin, China
by Qinghua Shang, Yuxia Wang, Dengfeng Wei and Longlong Chen
Processes 2025, 13(7), 2320; https://doi.org/10.3390/pr13072320 - 21 Jul 2025
Viewed by 434
Abstract
Capturing CO2 emitted by coal chemical enterprises and injecting it into oil reservoirs not only effectively improves the recovery rate and development efficiency of tight oil reservoirs in the Ordos Basin but also addresses the carbon emission problem constraining the development of [...] Read more.
Capturing CO2 emitted by coal chemical enterprises and injecting it into oil reservoirs not only effectively improves the recovery rate and development efficiency of tight oil reservoirs in the Ordos Basin but also addresses the carbon emission problem constraining the development of the region. Since initiating field experiments in 2012, the Ordos Basin has become a significant base for CCUS (Carbon capture, Utilization, and Storage) technology application and demonstration in China. However, over the years, projects have primarily focused on enhancing the recovery rate of CO2 flooding, while issues such as potential reservoir damage and its extent have received insufficient attention. This oversight hinder the long-term development and promotion of CO2 flooding technology in the region. Experimental results were comprehensively analyzed using techniques including nuclear magnetic resonance (NMR), X-ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma (ICP), and ion chromography (IG). The findings indicate that under current reservoir temperature and pressure conditions, significant asphaltene deposition and calcium carbonate precipitation do not occur during CO2 flooding. The reservoir’s characteristics-high feldspar content, low carbon mineral content, and low clay mineral content determine that the primary mechanism affecting physical properties under CO2 flooding in the Chang 4 + 5 tight sandstone reservoir is not, as traditional understand, carbon mineral dissolution or primary clay mineral expansion and migration. Instead, feldspar corrosion and secondary particles migration are the fundamental reasons for the changes in reservoir properties. As permeability increases, micro pore blockage decreases, and the damaging effect of CO2 flooding on reservoir permeability diminishes. Permeability and micro pore structure are therefore significant factors determining the damage degree of CO2 flooding inflicts on tight reservoirs. In addition, temperature and pressure have a significant impact on the extent of reservoir damage caused by CO2 flooding in the study region. At a given reservoir temperature, increasing CO2 injection pressure can mitigate reservoir damage. It is recommended to avoid conducting CO2 flooding projects in reservoirs with severe pressure attenuation, low permeability, and narrow pore throats as much as possible to prevent serious damage to the reservoir. At the same time, the production pressure difference should be reasonably controlled during the production process to reduce the risk and degree of calcium carbonate precipitation near oil production wells. Full article
(This article belongs to the Section Energy Systems)
Show Figures

Figure 1

20 pages, 16432 KiB  
Article
Application of Clustering Methods in Multivariate Data-Based Prospecting Prediction
by Xiaopeng Chang, Minghua Zhang, Liang Chen, Sheng Zhang, Wei Ren and Xiang Zhang
Minerals 2025, 15(7), 760; https://doi.org/10.3390/min15070760 - 20 Jul 2025
Viewed by 238
Abstract
Mining and analyzing information from multiple sources—such as geophysics and geochemistry—is a key aspect of big data-driven mineral prediction. Clustering, which groups large datasets based on distance metrics, is an essential method in multidimensional data analysis. The Two-Step Clustering (TSC) approach offers advantages [...] Read more.
Mining and analyzing information from multiple sources—such as geophysics and geochemistry—is a key aspect of big data-driven mineral prediction. Clustering, which groups large datasets based on distance metrics, is an essential method in multidimensional data analysis. The Two-Step Clustering (TSC) approach offers advantages by handling both categorical and continuous variables and automatically determining the optimal number of clusters. In this study, we applied the TSC method to mineral prediction in the northeastern margin of the Jiaolai Basin by: (i) converting residual gravity and magnetic anomalies into categorical variables using Ward clustering; and (ii) transforming 13 stream sediment elements into independent continuous variables through factor analysis. The results showed that clustering is sensitive to categorical variables and performs better with fewer categories. When variables share similar distribution characteristics, consistency between geophysical discretization and geochemical boundaries also influences clustering results. In this study, the (3 × 4) and (4 × 4) combinations yielded optimal clustering results. Cluster 3 was identified as a favorable zone for gold deposits due to its moderate gravity, low magnetism, and the enrichment in F1 (Ni–Cu–Zn), F2 (W–Mo–Bi), and F3 (As–Sb), indicating a multi-stage, shallow, hydrothermal mineralization process. This study demonstrates the effectiveness of combining Ward clustering for variable transformation with TSC for the integrated analysis of categorical and numerical data, confirming its value in multi-source data research and its potential for further application. Full article
Show Figures

Figure 1

18 pages, 7598 KiB  
Article
Recovery of Fine Rare Earth Minerals from Simulated Tin Tailings by Carrier Magnetic Separation: Selective Heterogeneous Agglomeration with Coarse Magnetite Particles
by Ilhwan Park, Topan Satria Gumilang, Rinaldi Yudha Pratama, Sanghee Jeon, Carlito Baltazar Tabelin, Theerayut Phengsaart, Muhammad Bilal, Youhei Kawamura and Mayumi Ito
Minerals 2025, 15(7), 757; https://doi.org/10.3390/min15070757 - 19 Jul 2025
Viewed by 336
Abstract
The demand for rare earth elements (REEs) is continuously increasing due to the important roles they play in low-carbon and green energy technologies. Unfortunately, the global REE reserves are limited and concentrated in only a few countries, so the reprocessing of alternative resources [...] Read more.
The demand for rare earth elements (REEs) is continuously increasing due to the important roles they play in low-carbon and green energy technologies. Unfortunately, the global REE reserves are limited and concentrated in only a few countries, so the reprocessing of alternative resources like tailings is of critical importance. This study investigated carrier magnetic separation using coarse magnetite particles as a carrier to recover finely ground monazite from tailings. The monazite and carrier surfaces were modified by sodium oleate (NaOL) to improve the hydrophobic interactions between them. The results of zeta potential and contact angle measurements implied the selective adsorption of NaOL onto the surfaces of the monazite and magnetite particles. Although their hydrophobicity increased, heterogenous agglomeration between them was not substantial. To improve heterogenous agglomeration, emulsified kerosene was utilized as a bridging liquid, resulting in more extensive attachment of fine monazite particles onto the surfaces of carrier particles and a dramatic improvement in monazite recovery by magnetic separation—from 0% (without carrier) to 70% (with carrier). A rougher–scavenger–cleaner carrier magnetic separation can produce REE concentrates with a total rare earth oxide (TREO) recovery of 80% and a grade of 9%, increased from 3.4%, which can be further increased to 23.2% after separating REEs and the carrier. Full article
Show Figures

Figure 1

23 pages, 8957 KiB  
Article
Geometallurgical Cluster Creation in a Niobium Deposit Using Dual-Space Clustering and Hierarchical Indicator Kriging with Trends
by João Felipe C. L. Costa, Fernanda G. F. Niquini, Claudio L. Schneider, Rodrigo M. Alcântara, Luciano N. Capponi and Rafael S. Rodrigues
Minerals 2025, 15(7), 755; https://doi.org/10.3390/min15070755 - 19 Jul 2025
Viewed by 354
Abstract
Alkaline carbonatite complexes are formed by magmatic, hydrothermal, and weathering geological events, which modify the minerals present in the rocks, resulting in ores with varied metallurgical behavior. To better spatially distinguish ores with distinct plant responses, creating a 3D geometallurgical block model was [...] Read more.
Alkaline carbonatite complexes are formed by magmatic, hydrothermal, and weathering geological events, which modify the minerals present in the rocks, resulting in ores with varied metallurgical behavior. To better spatially distinguish ores with distinct plant responses, creating a 3D geometallurgical block model was necessary. To establish the clusters, four different algorithms were tested: K-Means, Hierarchical Agglomerative Clustering, dual-space clustering (DSC), and clustering by autocorrelation statistics. The chosen method was DSC, which can consider the multivariate and spatial aspects of data simultaneously. To better understand each cluster’s mineralogy, an XRD analysis was conducted, shedding light on why each cluster performs differently in the plant: cluster 0 contains high magnetite content, explaining its strong magnetic yield; cluster 3 has low pyrochlore, resulting in reduced flotation yield; cluster 2 shows high pyrochlore and low gangue minerals, leading to the best overall performance; cluster 1 contains significant quartz and monazite, indicating relevance for rare earth elements. A hierarchical indicator kriging workflow incorporating a stochastic partial differential equation (SPDE) trend model was applied to spatially map these domains. This improved the deposit’s circular geometry reproduction and better represented the lithological distribution. The elaborated model allowed the identification of four geometallurgical zones with distinct mineralogical profiles and processing behaviors, leading to a more robust model for operational decision-making. Full article
(This article belongs to the Special Issue Geostatistical Methods and Practices for Specific Ore Deposits)
Show Figures

Figure 1

Back to TopTop