Diatomite, a natural adsorbent rich in active silica, serves as a valuable precursor for geopolymer synthesis. The safe disposal of diatomite as a failed lead (Pb(II)) adsorbent is critical to prevent secondary contamination. This study investigated the immobilisation efficiency of geopolymerisation for Pb(II)-rich diatomite sludge. Low-grade diatomite with high ignition loss was utilised in the synthesis of alkali-activated geopolymers. It was demonstrated that the geopolymers achieved a compressive strength of 28.3 MPa with a 50% replacement rate of metakaolin by diatomite sludge, which was not a compromise in strength compared to that of the geopolymer with no Pb(II) (26.2 MPa). The leaching behaviour of Pb(II) was evaluated using water and acetic acid, yielding concentrations below 3 mg/L and immobilisation efficiencies of 95% in both scenarios. Analytical techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) elucidated the mineral composition and chemical environment of the geopolymers. These analyses revealed that Pb(II) migrated from diatomite pores, potentially forming soluble hydroxides under sufficient hydroxide, which then participated in condensation with silicon and aluminium monomers, effectively immobilising Pb(II) within amorphous aluminosilicate gels. Furthermore, the formation of the amorphous gels within diatomite pores hindered Pb(II) leaching, encapsulating Pb(II) effectively. This study presents a novel approach to immobilising heavy metals within building materials, enhancing mineral resource utilisation efficiency while addressing environmental contamination concerns.
{"title":"Towards Safe Diatomite Sludge Management: Lead Immobilisation via Geopolymerisation","authors":"Haozhe Guo, Zhihao Huang, Baifa Zhang, Ting Yu, Thammaros Pantongsuk, Peng Yuan","doi":"10.3390/min14080763","DOIUrl":"https://doi.org/10.3390/min14080763","url":null,"abstract":"Diatomite, a natural adsorbent rich in active silica, serves as a valuable precursor for geopolymer synthesis. The safe disposal of diatomite as a failed lead (Pb(II)) adsorbent is critical to prevent secondary contamination. This study investigated the immobilisation efficiency of geopolymerisation for Pb(II)-rich diatomite sludge. Low-grade diatomite with high ignition loss was utilised in the synthesis of alkali-activated geopolymers. It was demonstrated that the geopolymers achieved a compressive strength of 28.3 MPa with a 50% replacement rate of metakaolin by diatomite sludge, which was not a compromise in strength compared to that of the geopolymer with no Pb(II) (26.2 MPa). The leaching behaviour of Pb(II) was evaluated using water and acetic acid, yielding concentrations below 3 mg/L and immobilisation efficiencies of 95% in both scenarios. Analytical techniques including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) elucidated the mineral composition and chemical environment of the geopolymers. These analyses revealed that Pb(II) migrated from diatomite pores, potentially forming soluble hydroxides under sufficient hydroxide, which then participated in condensation with silicon and aluminium monomers, effectively immobilising Pb(II) within amorphous aluminosilicate gels. Furthermore, the formation of the amorphous gels within diatomite pores hindered Pb(II) leaching, encapsulating Pb(II) effectively. This study presents a novel approach to immobilising heavy metals within building materials, enhancing mineral resource utilisation efficiency while addressing environmental contamination concerns.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leopoldo Córdova, Aaron Moya, Diana Comte, Igor Bravo
The design of tailings dams has improved significantly in recent decades due to experience and advances in applied research. However, there are still several environmental and geomechanical uncertainties associated with the response of these structures. Failures on the wall of tailings dams are well documented, where the most common causes are related to the action of water overtopping, slope instability, seepage, and foundation failure. Measuring the humidity or the saturation level at tailings dam walls has become a must do in the recent years. Resistivity monitoring using electrical resistivity tomography (ERT) techniques has proven to be one of the tools that provide good subsurface characterization for internal erosion detection and seepage assessment to evaluate potential environmental risks and the physical stability of tailings dams. Also, the integrated techniques of geotechnical, geophysical, and geochemical data have been used to correlate, coordinate, and improve the characterization. In this research, a procedure to guide us to a new methodology of acquiring and monitoring humidity content is presented, in which 2D electrical resistivity tomography (ERT) profiles are linked to the degree of soil saturation, using moisture sensors installed in a nearby well. The ERT profiles provide a 2D resistivity profile, and the moisture sensors can measure resistivity and volumetric water content (VWC) at a given installation depth. This second measure (VWC), with a defined total porosity, can be combined with Archie’s empirical law to obtain the degree of saturation, allowing the possibility to create remote monitoring suitable for mining operations without excessive laboratory testing.
{"title":"Methodology for the Identification of Moisture Content in Tailings Dam Walls Based on Electrical Resistivity Tomography Technique","authors":"Leopoldo Córdova, Aaron Moya, Diana Comte, Igor Bravo","doi":"10.3390/min14080760","DOIUrl":"https://doi.org/10.3390/min14080760","url":null,"abstract":"The design of tailings dams has improved significantly in recent decades due to experience and advances in applied research. However, there are still several environmental and geomechanical uncertainties associated with the response of these structures. Failures on the wall of tailings dams are well documented, where the most common causes are related to the action of water overtopping, slope instability, seepage, and foundation failure. Measuring the humidity or the saturation level at tailings dam walls has become a must do in the recent years. Resistivity monitoring using electrical resistivity tomography (ERT) techniques has proven to be one of the tools that provide good subsurface characterization for internal erosion detection and seepage assessment to evaluate potential environmental risks and the physical stability of tailings dams. Also, the integrated techniques of geotechnical, geophysical, and geochemical data have been used to correlate, coordinate, and improve the characterization. In this research, a procedure to guide us to a new methodology of acquiring and monitoring humidity content is presented, in which 2D electrical resistivity tomography (ERT) profiles are linked to the degree of soil saturation, using moisture sensors installed in a nearby well. The ERT profiles provide a 2D resistivity profile, and the moisture sensors can measure resistivity and volumetric water content (VWC) at a given installation depth. This second measure (VWC), with a defined total porosity, can be combined with Archie’s empirical law to obtain the degree of saturation, allowing the possibility to create remote monitoring suitable for mining operations without excessive laboratory testing.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guangxu Bi, Xiangyu Li, Xiaochong Du, Xinhua Sun, Wenpeng Yao
The energy sector is the sector that generates the highest amount of environmental contamination, especially in water sources, mostly in the case of coal-based energy production. The aim of this study was to examine a significant contamination source, heavy metal contamination, in coal mining effluents. The current investigation introduces an MOF platform based on zirconium clusters and isophthalic acid with NH2-MIP-SO3H mixed amine and sulfonic acid functional groups in order to remove the most common heavy metal ions in coal mining effluents, including Hg, Cd, Pb, and Cu ions. The water matrix and the operational conditions were identified to be very influential in the removal process, such as the pH of water, the initial metal concentration and operating time. NH2-MIP-SO3H offers a great removal efficiency of metals starting from 745.83 mg/g for Cd, 673.67 mg/g for Cu, 589.85 mg/g for Hg, and 481.66 mg/g for Pb ions, with the Langmuir equation for equilibrium and pseudo-second-order equation for kinetics being the ideal models to express the equilibrium and kinetic data, respectively. A significant impact of water pH was found to occur, with the NH2-MIP-SO3H platform performing best at pH 6. Reuse of NH2-MIP-SO3H demonstrates excellent reusability, sustaining 90% of initial performance over eight regeneration cycles. The interaction of functional group-functional metal was the dominant mechanism in the removal process. The NH2-MIP-SO3H unique approach to heavy metal removal provides a very hopeful outlook for additional investigations in larger-scale studies.
{"title":"Remediation of Heavy Metal Pollution from Coal Mine Effluent Using Metal-Organic Frameworks(MOF): Impact of Water Media, Operational Factors and Metal Characteristics","authors":"Guangxu Bi, Xiangyu Li, Xiaochong Du, Xinhua Sun, Wenpeng Yao","doi":"10.3390/min14080764","DOIUrl":"https://doi.org/10.3390/min14080764","url":null,"abstract":"The energy sector is the sector that generates the highest amount of environmental contamination, especially in water sources, mostly in the case of coal-based energy production. The aim of this study was to examine a significant contamination source, heavy metal contamination, in coal mining effluents. The current investigation introduces an MOF platform based on zirconium clusters and isophthalic acid with NH2-MIP-SO3H mixed amine and sulfonic acid functional groups in order to remove the most common heavy metal ions in coal mining effluents, including Hg, Cd, Pb, and Cu ions. The water matrix and the operational conditions were identified to be very influential in the removal process, such as the pH of water, the initial metal concentration and operating time. NH2-MIP-SO3H offers a great removal efficiency of metals starting from 745.83 mg/g for Cd, 673.67 mg/g for Cu, 589.85 mg/g for Hg, and 481.66 mg/g for Pb ions, with the Langmuir equation for equilibrium and pseudo-second-order equation for kinetics being the ideal models to express the equilibrium and kinetic data, respectively. A significant impact of water pH was found to occur, with the NH2-MIP-SO3H platform performing best at pH 6. Reuse of NH2-MIP-SO3H demonstrates excellent reusability, sustaining 90% of initial performance over eight regeneration cycles. The interaction of functional group-functional metal was the dominant mechanism in the removal process. The NH2-MIP-SO3H unique approach to heavy metal removal provides a very hopeful outlook for additional investigations in larger-scale studies.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
As the global demand for tellurium (Te) increases, it is crucial to develop efficient recovery methods that consider existing supply streams. This research combines gravity separation and froth flotation processes to enhance the recovery of Te minerals from tailings produced during the beneficiation of copper porphyry ores. Prior to processing, a systematic and comprehensive characterization study of copper tailing (CT) samples was conducted to examine the deportment of Te minerals in different mineral phases and to understand their locking and liberation behavior. Characterization techniques included inductively coupled plasma mass spectrometry (ICP-MS) and TESCAN’s integrated mineral analysis (TIMA). Copper tailing characterization showed that minerals with gold (Au), silver (Ag), bismuth (Bi), and Te were present in various forms, including native Au, electrum, tellurides, and sulfosalts. TIMA revealed that >90% of these minerals were primarily hosted in pyrite as less than 10 µm inclusions in the CT. TIMA also revealed that Te minerals exhibited fine-grained liberation of less than 20 μm. Moreover, TIMA results showed that >80% of mica and other silicate minerals were concentrated in size fractions < 38 μm, suggesting that desliming processes would positively impact Te enrichment. The results from the processing tests showed a Te recovery rate of ~77% and a Te enrichment ratio of 13 when using the combination of gravity separation and froth flotation at 90 g/t xanthate collector and 50 g/t glycol frother. The findings from this study show a significant potential for Te recovery from unconventional sources if appropriate physical beneficiation approaches are adopted.
{"title":"Tellurium Enrichment in Copper Tailings: A Mineralogical and Processing Study","authors":"José L. Corchado-Albelo, Lana Alagha","doi":"10.3390/min14080761","DOIUrl":"https://doi.org/10.3390/min14080761","url":null,"abstract":"As the global demand for tellurium (Te) increases, it is crucial to develop efficient recovery methods that consider existing supply streams. This research combines gravity separation and froth flotation processes to enhance the recovery of Te minerals from tailings produced during the beneficiation of copper porphyry ores. Prior to processing, a systematic and comprehensive characterization study of copper tailing (CT) samples was conducted to examine the deportment of Te minerals in different mineral phases and to understand their locking and liberation behavior. Characterization techniques included inductively coupled plasma mass spectrometry (ICP-MS) and TESCAN’s integrated mineral analysis (TIMA). Copper tailing characterization showed that minerals with gold (Au), silver (Ag), bismuth (Bi), and Te were present in various forms, including native Au, electrum, tellurides, and sulfosalts. TIMA revealed that >90% of these minerals were primarily hosted in pyrite as less than 10 µm inclusions in the CT. TIMA also revealed that Te minerals exhibited fine-grained liberation of less than 20 μm. Moreover, TIMA results showed that >80% of mica and other silicate minerals were concentrated in size fractions < 38 μm, suggesting that desliming processes would positively impact Te enrichment. The results from the processing tests showed a Te recovery rate of ~77% and a Te enrichment ratio of 13 when using the combination of gravity separation and froth flotation at 90 g/t xanthate collector and 50 g/t glycol frother. The findings from this study show a significant potential for Te recovery from unconventional sources if appropriate physical beneficiation approaches are adopted.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Early Jurassic was primarily a greenhouse phase in Earth’s history. Previous studies have predominantly focused on marine strata in the Tethyan Ocean, but continental records outside of Europe are still poorly understood, which has hindered a thorough understanding of its climate dynamics. To address this gap, organic, inorganic, and isotope geochemical analyses, along with mineralogical and sedimentological assessments, were conducted on samples from the Quemo Co Formation of well QZ-16 in the Qiangtang Basin (Eastern Tethys). This study aimed to investigate carbon cycle perturbations and consequences of redox conditions and paleosalinity within a lacustrine system during the Early Jurassic. The carbon isotope profile of well QZ-16 exhibited a long-term negative excursion of ca. −3.83‰ in lacustrine sediments, with relatively heavy δ13Corg values and small excursion magnitudes. Enhanced terrigenous input, as indicated by detrital proxies such as Si/Al, Ti/Al, and Zr/Al, was driven by accelerated continental weathering during the carbon isotope excursions. The presence of coarse-grained, pelitic siltstone deposits coincided with the onset of these negative carbon isotope excursions. Sr/Ba ratios (0.05–3.64, avg. 0.73) suggest a brackish to freshwater salinity regime within the third member, implying that the deposition of the Quemo Co Formation was influenced by both freshwater and seawater inputs. Most enrichment factors (VEF, ZnEF, NiEF) having a value below 1.0 and Corg/P ratios less than 50 indicate that the lacustrine environment was characterized by predominantly oxidizing conditions, particularly during the early Toarcian negative carbon isotope excursion (T-NCIE). Despite the record of the T-NCIE event, enhanced respiration in bottom and pore waters indicates that the Toarcian Oceanic Anoxic Event (T-OAE) was absent in this part of the eastern Tethys Ocean. The recorded Early Jurassic environmental settings in the Qiangtang Basin lacustrine system exhibit a close association with the T-CIE event (183 Ma), providing insights into the complex interplay between carbon cycle perturbation, climate, weathering, and biological processes during this greenhouse period.
{"title":"Lacustrine Environmental Perturbations during the Early Jurassic in the Qiangtang Basin, Northern Tibet","authors":"Haowei Zhang, Jian Wang, Mohamed Saad Ahmed, Xiugen Fu, Lijun Shen","doi":"10.3390/min14080762","DOIUrl":"https://doi.org/10.3390/min14080762","url":null,"abstract":"The Early Jurassic was primarily a greenhouse phase in Earth’s history. Previous studies have predominantly focused on marine strata in the Tethyan Ocean, but continental records outside of Europe are still poorly understood, which has hindered a thorough understanding of its climate dynamics. To address this gap, organic, inorganic, and isotope geochemical analyses, along with mineralogical and sedimentological assessments, were conducted on samples from the Quemo Co Formation of well QZ-16 in the Qiangtang Basin (Eastern Tethys). This study aimed to investigate carbon cycle perturbations and consequences of redox conditions and paleosalinity within a lacustrine system during the Early Jurassic. The carbon isotope profile of well QZ-16 exhibited a long-term negative excursion of ca. −3.83‰ in lacustrine sediments, with relatively heavy δ13Corg values and small excursion magnitudes. Enhanced terrigenous input, as indicated by detrital proxies such as Si/Al, Ti/Al, and Zr/Al, was driven by accelerated continental weathering during the carbon isotope excursions. The presence of coarse-grained, pelitic siltstone deposits coincided with the onset of these negative carbon isotope excursions. Sr/Ba ratios (0.05–3.64, avg. 0.73) suggest a brackish to freshwater salinity regime within the third member, implying that the deposition of the Quemo Co Formation was influenced by both freshwater and seawater inputs. Most enrichment factors (VEF, ZnEF, NiEF) having a value below 1.0 and Corg/P ratios less than 50 indicate that the lacustrine environment was characterized by predominantly oxidizing conditions, particularly during the early Toarcian negative carbon isotope excursion (T-NCIE). Despite the record of the T-NCIE event, enhanced respiration in bottom and pore waters indicates that the Toarcian Oceanic Anoxic Event (T-OAE) was absent in this part of the eastern Tethys Ocean. The recorded Early Jurassic environmental settings in the Qiangtang Basin lacustrine system exhibit a close association with the T-CIE event (183 Ma), providing insights into the complex interplay between carbon cycle perturbation, climate, weathering, and biological processes during this greenhouse period.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The discrete element method (DEM) is largely used to simulate the geotechnical behavior of granular materials. However, numerical modeling with this type of code is expensive and time consuming, especially when fine particles are involved. This leads researchers to make use of different approaches to shorten the time of calculation without verifying the stability and reliability of numerical results, even though a compromise between the time of calculation and accuracy is commonly claimed. The particle size distribution (PSD) curve of studied granular material is completely ignored or arbitrarily cut. It is unclear if the ensued numerical results are still representative of the studied granular materials. Additionally, one can see a large number of numerical models established on a basis of calibration by ignoring the physical meaning and even measured values of some model parameters. The representativeness and reliability of the obtained numerical results are questionable. All these partly contribute to reducing the public’s confidence in numerical modeling. In this study, a methodology is illustrated to obtain an optimal DEM model, which minimizes the time of calculation and ensures stable and reliable numerical results for the mechanical behavior of a waste rock. The results indicate that the PSD curve of the studied waste rock can indeed be cut by excluding a portion of fine particles, while the Young’s modulus of the waste rock particles can also be decreased to accelerate the numerical calculations. A physical explanation of why the time of calculation can be shortened by reducing the Young’s modulus of waste rock particles is provided for the first time. Overall, the PSD cut, reduction in Young’s modulus, and time step must be determined through sensitivity analyses to ensure stable and reliable results with the shortest time of calculation. In addition, it is important to minimize the number of model parameters determined through the process of calibration, especially for those having physical meanings. In this study, the only model parameter having a clear physical meaning but difficult to measure is the rolling resistance coefficient for repose angle tests on the studied waste rock. Its value has to be obtained through a process of calibration against some experimental results. The validity and predictability of the calibrated numerical model have been successfully verified against additional experimental results.
离散元法（DEM）主要用于模拟颗粒材料的岩土行为。然而，使用这种代码进行数值建模既昂贵又耗时，尤其是涉及细颗粒时。这就导致研究人员在不验证数值结果稳定性和可靠性的情况下，利用不同的方法来缩短计算时间，尽管人们普遍认为计算时间和精度之间需要折中。所研究颗粒材料的粒度分布（PSD）曲线被完全忽略或任意切割。由此得出的数值结果是否仍能代表所研究的颗粒材料尚不清楚。此外，我们还可以看到大量建立在校准基础上的数值模型忽略了某些模型参数的物理意义甚至测量值。这些数值结果的代表性和可靠性都值得怀疑。所有这些都在一定程度上降低了公众对数值模拟的信心。本研究阐述了获得最佳 DEM 模型的方法，该模型可最大限度地缩短计算时间，并确保获得稳定可靠的废石力学行为数值结果。结果表明，所研究废石的 PSD 曲线确实可以通过剔除部分细颗粒来削减，而废石颗粒的杨氏模量也可以通过降低来加速数值计算。我们首次用物理方法解释了为什么降低废石颗粒的杨氏模量可以缩短计算时间。总之，必须通过敏感性分析确定 PSD 切分、杨氏模量减小和时间步长，以确保在最短计算时间内获得稳定可靠的结果。此外，必须尽量减少通过校准过程确定的模型参数数量，尤其是那些具有物理意义的参数。在本研究中，唯一具有明确物理意义但难以测量的模型参数是对所研究废石进行休止角试验时的滚动阻力系数。它的值必须通过与一些实验结果进行校准来获得。校准后的数值模型的有效性和可预测性已通过其他实验结果得到成功验证。
{"title":"Optimization of Discrete Element Method Model to Obtain Stable and Reliable Numerical Results of Mechanical Response of Granular Materials","authors":"Yuyu Zhang, Li Li","doi":"10.3390/min14080758","DOIUrl":"https://doi.org/10.3390/min14080758","url":null,"abstract":"The discrete element method (DEM) is largely used to simulate the geotechnical behavior of granular materials. However, numerical modeling with this type of code is expensive and time consuming, especially when fine particles are involved. This leads researchers to make use of different approaches to shorten the time of calculation without verifying the stability and reliability of numerical results, even though a compromise between the time of calculation and accuracy is commonly claimed. The particle size distribution (PSD) curve of studied granular material is completely ignored or arbitrarily cut. It is unclear if the ensued numerical results are still representative of the studied granular materials. Additionally, one can see a large number of numerical models established on a basis of calibration by ignoring the physical meaning and even measured values of some model parameters. The representativeness and reliability of the obtained numerical results are questionable. All these partly contribute to reducing the public’s confidence in numerical modeling. In this study, a methodology is illustrated to obtain an optimal DEM model, which minimizes the time of calculation and ensures stable and reliable numerical results for the mechanical behavior of a waste rock. The results indicate that the PSD curve of the studied waste rock can indeed be cut by excluding a portion of fine particles, while the Young’s modulus of the waste rock particles can also be decreased to accelerate the numerical calculations. A physical explanation of why the time of calculation can be shortened by reducing the Young’s modulus of waste rock particles is provided for the first time. Overall, the PSD cut, reduction in Young’s modulus, and time step must be determined through sensitivity analyses to ensure stable and reliable results with the shortest time of calculation. In addition, it is important to minimize the number of model parameters determined through the process of calibration, especially for those having physical meanings. In this study, the only model parameter having a clear physical meaning but difficult to measure is the rolling resistance coefficient for repose angle tests on the studied waste rock. Its value has to be obtained through a process of calibration against some experimental results. The validity and predictability of the calibrated numerical model have been successfully verified against additional experimental results.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rare metals (usually defined as including elements such as Li, Rb, Cs, Be, Sn, Nb, Ta, Zr, Y, U, and rare-earth elements) are included in the list of “critical mineral resources” by major economies around the world [...]
{"title":"Editorial for Special Issue “Rare Metal Ore Formations and Rare Metal Metallogeny”","authors":"Peng Li, Jiankang Li","doi":"10.3390/min14080759","DOIUrl":"https://doi.org/10.3390/min14080759","url":null,"abstract":"Rare metals (usually defined as including elements such as Li, Rb, Cs, Be, Sn, Nb, Ta, Zr, Y, U, and rare-earth elements) are included in the list of “critical mineral resources” by major economies around the world [...]","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iman Hasanizadeh, Hamid Khoshdast, Mehdi Safari, Kaveh Asgari, Ahmad Rahmanian
This research assesses the effect of carbonated pyrolysis oil (CPO) derived from scrap car tires on the metallurgical efficiency of coal flotation as a flotation additive. Using a statistical experimental design, the influence of various operational variables, including solid percent of feed pulp and dosages of reagents, i.e., CPO as an additive, diesel oil as a collector, and pine oil as a frother, on the ash content and yield of the final concentrate were investigated. Experimental data vary significantly based on operational conditions, ranging from 6.6% ash content with a 15% yield to 19.1% ash content with a 76.8% yield. The composition of the pyrolysis oil was identified by using Fourier transform infrared spectroscopy (FTIR). The analysis of variance (ANOVA) of experimental results demonstrated that almost all variables had a substantial effect on the flotation responses, positive or negative, depending on the variable or variable interaction. It was discovered that the usage of CPO intensified the total yield and ash content of concentrate in a nonlinear fashion in a range of 15% and 4%, respectively. The results revealed a non-selective interaction effect between CPO and pine oil, as well as competitive adsorption between diesel oil and CPO, which contributed to the curved behavior of flotation measurements. The detrimental effect of CPO on the flotation response of the studied coal sample was also related to the interaction of the hydrophilic groups in the CPO structure and the oxide groups of ash material in coal particles. This work shows the potential of carbonated pyrolysis oil to enhance coal flotation performance and sheds light on the underlying mechanisms.
{"title":"Influence of Carbonated Pyrolysis Oil Recycled from Scrap Tires on Metallurgical Efficiency of Coal Flotation","authors":"Iman Hasanizadeh, Hamid Khoshdast, Mehdi Safari, Kaveh Asgari, Ahmad Rahmanian","doi":"10.3390/min14080765","DOIUrl":"https://doi.org/10.3390/min14080765","url":null,"abstract":"This research assesses the effect of carbonated pyrolysis oil (CPO) derived from scrap car tires on the metallurgical efficiency of coal flotation as a flotation additive. Using a statistical experimental design, the influence of various operational variables, including solid percent of feed pulp and dosages of reagents, i.e., CPO as an additive, diesel oil as a collector, and pine oil as a frother, on the ash content and yield of the final concentrate were investigated. Experimental data vary significantly based on operational conditions, ranging from 6.6% ash content with a 15% yield to 19.1% ash content with a 76.8% yield. The composition of the pyrolysis oil was identified by using Fourier transform infrared spectroscopy (FTIR). The analysis of variance (ANOVA) of experimental results demonstrated that almost all variables had a substantial effect on the flotation responses, positive or negative, depending on the variable or variable interaction. It was discovered that the usage of CPO intensified the total yield and ash content of concentrate in a nonlinear fashion in a range of 15% and 4%, respectively. The results revealed a non-selective interaction effect between CPO and pine oil, as well as competitive adsorption between diesel oil and CPO, which contributed to the curved behavior of flotation measurements. The detrimental effect of CPO on the flotation response of the studied coal sample was also related to the interaction of the hydrophilic groups in the CPO structure and the oxide groups of ash material in coal particles. This work shows the potential of carbonated pyrolysis oil to enhance coal flotation performance and sheds light on the underlying mechanisms.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141864885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the increasing need for rare-earth elements (REEs) to reach the goals of the ongoing green energy transition, new and innovative methods are needed to identify new primary resources of these critical metals. This study explores the potential to use a non-biased, uniform till dataset to generate evidentiary layers that describe these critical factors and geochemical anomalies to aid mineral potential mapping (MPM) for REEs using machine-assisted methods. The till samples used in this study were collected from the “REE Line”, a sub-region within the Bergslagen lithotectonic province, Sweden, where numerous REE mineralizations occur. Multiple approaches were used in this study to isolate geochemical anomalies using multivariate methods, namely principal component analysis (PCA) and K-means clustering. Additional factors for classifying till samples were also tested, including alteration indices. Using known REE occurrences in Bergslagen as validation points, the results demonstrated the usefulness of multivariate methods applied to till geochemistry for predictive bedrock mapping, and to identify potential areas of REE mineralization within the REE line. The results of the alteration indices showed that the till geochemistry demonstrated similar levels of alteration when compared to the underlying bedrock, allowing for a regional alteration map to be generated. These results show that regional-scale till sampling can provide low-cost data for mineral exploration at the regional scale and generate usable evidentiary layers for GIS-based MPM.
随着人们对稀土元素（REE）的需求不断增加，以实现正在进行的绿色能源转型的目标，需要采用新的创新方法来确定这些关键金属的新原生资源。本研究探讨了使用无偏见、统一的耕层数据集生成证据层的可能性，这些证据层描述了这些关键因素和地球化学异常，有助于使用机器辅助方法绘制稀土元素的矿产潜力图（MPM）。本研究使用的耕层样本采集自 "REE 线"，这是瑞典 Bergslagen 岩石构造省内的一个子区域，在该区域出现了大量的 REE 矿化现象。本研究采用多种方法，即主成分分析（PCA）和 K-均值聚类，来分离地球化学异常。此外，还测试了对 till 样品进行分类的其他因素，包括蚀变指数。使用 Bergslagen 的已知 REE 矿点作为验证点，结果表明将多元方法应用于 till 地球化学对预测基岩绘图以及确定 REE 线路内潜在的 REE 矿化区域非常有用。蚀变指数的结果表明，与下伏基岩相比，耕层地球化学显示出相似的蚀变程度，从而可以生成区域蚀变图。这些结果表明，区域尺度的耕层取样可以为区域尺度的矿产勘探提供低成本的数据，并为基于地理信息系统的多指标监测生成可用的证据层。
{"title":"Derivation of Predictive Layers Using Regional Till Geochemistry Data for Mineral Potential Mapping of the REE Line of Bergslagen, Central Sweden","authors":"Patrick Casey, George Morris, Martiya Sadeghi","doi":"10.3390/min14080753","DOIUrl":"https://doi.org/10.3390/min14080753","url":null,"abstract":"With the increasing need for rare-earth elements (REEs) to reach the goals of the ongoing green energy transition, new and innovative methods are needed to identify new primary resources of these critical metals. This study explores the potential to use a non-biased, uniform till dataset to generate evidentiary layers that describe these critical factors and geochemical anomalies to aid mineral potential mapping (MPM) for REEs using machine-assisted methods. The till samples used in this study were collected from the “REE Line”, a sub-region within the Bergslagen lithotectonic province, Sweden, where numerous REE mineralizations occur. Multiple approaches were used in this study to isolate geochemical anomalies using multivariate methods, namely principal component analysis (PCA) and K-means clustering. Additional factors for classifying till samples were also tested, including alteration indices. Using known REE occurrences in Bergslagen as validation points, the results demonstrated the usefulness of multivariate methods applied to till geochemistry for predictive bedrock mapping, and to identify potential areas of REE mineralization within the REE line. The results of the alteration indices showed that the till geochemistry demonstrated similar levels of alteration when compared to the underlying bedrock, allowing for a regional alteration map to be generated. These results show that regional-scale till sampling can provide low-cost data for mineral exploration at the regional scale and generate usable evidentiary layers for GIS-based MPM.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141772481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yangchen Drolma, Kaijun Li, Yubin Li, Jinshu Zhang, Chengye Yang, Gen Zhang, Ruoming Li, Duo Liu
Himalayan leucogranite is an excellent target for understanding the orogenic process of the India–Asia collision, but its origin and tectonic significance are still under debate. An integrated study of geochronology, geochemistry, and in situ Sr-Nd-Hf isotopes was conducted for a tourmaline-bearing leucogranite in the eastern Tethyan Himalaya using LA-ICP-MS, X-ray fluorescence spectroscopy, and ICP-MS and LA-MC-ICP-MS, respectively. LA-ICP-MS U-Pb dating of zircon and monazite showed that it was emplaced at ~19 Ma. The leucogranite had high SiO2 and Al2O3 contents ranging from 73.16 to 73.99 wt.% and 15.05 to 15.24 wt.%, respectively. It was characterized by a high aluminum saturation index (1.14–1.19) and Rb/Sr ratio (3.58–6.35), which is characteristic of S-type granite. The leucogranite was enriched in light rare-earth elements (LREEs; e.g., La and Ce) and large ion lithophile elements (LILEs; e.g., Rb, K, and Pb) and depleted in heavy rare-earth elements (e.g., Tm, Yb, and Lu) and high field strength elements (HFSEs; e.g., Nb, Zr, and Ti). It was characterized by high I Sr (t) (0.7268–0.7281) and low ε Nd (t) (−14.6 to −13.2) and ε Hf (t) (−12.6 to −9.47), which was consistent with the isotopic characteristics of the Higher Himalayan Sequence. Petrogenetically, the origin of the leucogranite is best explained by the decompression-induced muscovite dehydration melting of an ancient metapelitic source within the Higher Himalayan Sequence during regional extension due to the movement of the South Tibetan Detachment System (STDS). The significantly high lithium and beryllium contents of the leucogranite and associated pegmatite suggest that Himalayan leucogranites possess huge potential for lithium and beryllium exploration.
{"title":"Geochronology, Geochemistry, and In Situ Sr-Nd-Hf Isotopic Compositions of a Tourmaline-Bearing Leucogranite in Eastern Tethyan Himalaya: Implications for Tectonic Setting and Rare Metal Mineralization","authors":"Yangchen Drolma, Kaijun Li, Yubin Li, Jinshu Zhang, Chengye Yang, Gen Zhang, Ruoming Li, Duo Liu","doi":"10.3390/min14080755","DOIUrl":"https://doi.org/10.3390/min14080755","url":null,"abstract":"Himalayan leucogranite is an excellent target for understanding the orogenic process of the India–Asia collision, but its origin and tectonic significance are still under debate. An integrated study of geochronology, geochemistry, and in situ Sr-Nd-Hf isotopes was conducted for a tourmaline-bearing leucogranite in the eastern Tethyan Himalaya using LA-ICP-MS, X-ray fluorescence spectroscopy, and ICP-MS and LA-MC-ICP-MS, respectively. LA-ICP-MS U-Pb dating of zircon and monazite showed that it was emplaced at ~19 Ma. The leucogranite had high SiO2 and Al2O3 contents ranging from 73.16 to 73.99 wt.% and 15.05 to 15.24 wt.%, respectively. It was characterized by a high aluminum saturation index (1.14–1.19) and Rb/Sr ratio (3.58–6.35), which is characteristic of S-type granite. The leucogranite was enriched in light rare-earth elements (LREEs; e.g., La and Ce) and large ion lithophile elements (LILEs; e.g., Rb, K, and Pb) and depleted in heavy rare-earth elements (e.g., Tm, Yb, and Lu) and high field strength elements (HFSEs; e.g., Nb, Zr, and Ti). It was characterized by high I Sr (t) (0.7268–0.7281) and low ε Nd (t) (−14.6 to −13.2) and ε Hf (t) (−12.6 to −9.47), which was consistent with the isotopic characteristics of the Higher Himalayan Sequence. Petrogenetically, the origin of the leucogranite is best explained by the decompression-induced muscovite dehydration melting of an ancient metapelitic source within the Higher Himalayan Sequence during regional extension due to the movement of the South Tibetan Detachment System (STDS). The significantly high lithium and beryllium contents of the leucogranite and associated pegmatite suggest that Himalayan leucogranites possess huge potential for lithium and beryllium exploration.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141772484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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