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Innovative pilot-scale process for sustainable rare earth oxide production from coal byproducts:A comprehensive environmental impact assessment

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Journal of Rare Earths 2025年第2期43卷 397-404页

作者： Mohsen Rabbani Joshua Werner Ario Fahimi Ehsan Vahidi Department of mining and Metallurgical engineering Mackay School of Earth Sciences and EngineeringUniversity of Nevada Department of mining engineering University of Kentucky

This study developed a pilot-scale process feeding with two different materials resulting from a column leaching process and acid mine drainage（AMD） streams to recover rare earth elements（REEs）.A life cycle assessment（LCA） study was done to evaluate the environmental impacts of rare earth production from deleterious material in the form of highly contaminated leachate（HCL） and low-contaminated leachate（LCL）.The results indicate that the main contributors to environmental categories that produce RE-hydroxide stages are NaOH and ***,oxalic acid,Na2CO3,and hydrochloric acid significantly contribute to the production stage of individual rare earth oxides（REOs）,including solvent extraction（SX） and precipitation *** HCL route has higher environmental impacts than LCL due to higher chemical/energy and H2SO4usage,so 468 and 292 kg of carbon dioxide are generated to produce1 t of individual REOs from HCL and LCL routes,***,the carbon dioxide emitted from the process,including the RE-hydroxide production,SX,and REOs production,is less than 10 t CO2.A sensitivity analysis was also performed to assess the changeability of the environmental footprints of the main inputs in the SX process,as the main stage has a higher contribution to the whole *** LCA study is the first step toward understanding the environmental influence of new processing methods to produce REEs from coal by-products through a developed pilot-scale process.

关键词： Coal by-products Environmental impacts Life cycle assessment Precipitation Rare earth elements Rare earth oxide

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Asymptotic Analysis of Epidemics on Networks

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Journal of Systems Science & Complexity 2025年第01期 338-348页

作者： SOLO Victor school of Electrical engineering and Telecommunications unsw Sydney

Driven partly by cyber-security issues there is growing interest in modelling epidemics on networks. However it turns out that there are some gaps in the formulation of these network models that have precluded a proper study of stochastic fluctuations. The author revisits some popular models,rectify their shortcomings and then develops an asymptotic analysis of their behaviour.

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Response properties of geometries of coal penetrating fracture on seepage behavior

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International Journal of mining Science and Technology 2025年第2期35卷 191-211页

作者： Penghua Han Kai Wang Jiewen Pang Xiaofeng Ji Cun Zhang College of engineering for Safety and Emergency Management Taiyuan University of Science and TechnologyTaiyuan 030024China school of Energy and mining engineering China University of Mining and Technology-BeijingBeijing 100083China engineering Research Center of Green and Intelligent mining for Thick Coal Seam Ministry of EducationChina University of Mining and Technology-BeijingBeijing 100083China

The fracture surfaces of coal-rock masses formed under mining-induced stress generally exhibit complex geometries, and the fracture geometry is one of the primary factors affecting the seepage characteristics of coal-rock penetrating fracture. This paper investigates the seepage characteristics of 5 groups of coal penetrating fracture(CPF) with different joint roughness coefficients(JRCs). Based on 3D morphology scanner tests and hydraulic coupling tests, a characterization method of effective geometric parameters in fracture surfaces under various confining pressures was improved, and a relationship between effective geometric parameters and the confining pressure is established. The results indicate that the nonlinear flow behavior in a CPF primarily includes three types: non-Newtonian fluid seepage under high confining pressure and low JRC, non-Darcy seepage under low confining pressure and high JRC, and the whole process of seepage characteristics between these two conditions. Among them, nonNewtonian fluid seepage is caused by significant fracture expansion, while non-Darcy seepage can be attributed to turbulence effects. During the seepage process, the geometric parameters with different JRC fracture samples all exhibit exponential changes with the increase of confining pressure. In addition,under high confining pressure, the effective contact ratio, effective fracture aperture, and void deviation ratio with high JRC fracture samples under high confining pressure increase by 93.5%, 67.4%, and 24.9%,respectively, compared with those of low JRC fracture samples. According to the variation of geometric parameters in a CPF with external stress, a seepage model considering geometric parameters in a CPF is proposed. By introducing the root mean square error(RMSE) and coefficient of determination(R2) to evaluate the error and goodness of fit between model curves and experimental data, it is found that the theoretical curves of model in this paper have the best matchi

关键词： Coal penetrating fracture Roughness Geometries Seepage characteristics

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Deformation mechanism and NPR anchor cable truss coupling support in tunnel through fault fracture zone

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Journal of Mountain Science 2025年第1期22卷 354-374页

作者： HUO Shusen TAO Zhigang HE Manchao WANG Fengnian XU Chuang State Key Laboratory for Geomechanics and Deep Underground engineering China University of Mining and Technology(Beijing)Beijing 100083China school of Mechanics and Civil engineering China University of Mining and Technology(Beijing)Beijing 100083China

To address the issue of extensive deformation in the Tabaiyi Tunnel caused by the fault zone,nuclear magnetic resonance(NMR)technology was employed to analyze the physical and mechanical properties of waterabsorbing *** analysis aimed to understand the mechanism behind the significant *** from the principle of excavation stress compensation,a support scheme featuring NPR anchorcables and an asymmetric truss support system was *** validate the scheme,numerical analysis using a combination of the Discrete Element Method(DEM)-Finite Element Method(FEM)was ***,similar material model tests and engineering measurements were carried *** experiments were also performed to evaluate the NPR anchor-cable and truss support system,focusing on anchor cable forces,pressures between the truss and surrounding rock,pressures between the initial support and secondary lining,as well as the magnitude of settlement and convergence deformation in the surrounding *** results indicate that the waterinduced expansion of clay minerals,resulting from damage caused by fissure water,accelerated the softening of the mudstone's internal structure,leading to significant deformations in the Tabaiyi Tunnel under high tectonic *** original support design fell short as the length of the anchor rods was smaller than the expansion depth of the plastic *** a result,the initial support structure bore the entire load from the surrounding rock,and a non-coupled deformation contact was observed between the double-arch truss and the surrounding *** adoption of NPR asymmetric anchor-cable support effectively restrained the expansion and asymmetric distribution characteristics of the plastic *** the mechanical degradation caused by water absorption in mudstone,the rigid constraint provided by the truss proved crucial for controlling the stability of the surrounding *** research findings hold significant implicatio

关键词： Fault fracture zone Large deformation Nuclear magnetic resonance NPR anchor cable truss support Coupled simulation

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Experiments on image data augmentation techniques for geological rock type classification with convolutional neural networks

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Journal of Rock Mechanics and Geotechnical engineering 2025年第1期17卷 106-125页

作者： Afshin Tatar Manouchehr Haghighi Abbas Zeinijahromi school of Chemical engineering Discipline of Mining and Petroleum EngineeringThe University of AdelaideAdelaideSA 5005Australia

The integration of image analysis through deep learning(DL)into rock classification represents a significant leap forward in geological *** traditional methods remain invaluable for their expertise and historical context,DL offers a powerful complement by enhancing the speed,objectivity,and precision of the classification *** research explores the significance of image data augmentation techniques in optimizing the performance of convolutional neural networks(CNNs)for geological image analysis,particularly in the classification of igneous,metamorphic,and sedimentary rock types from rock thin section(RTS)*** study primarily focuses on classic image augmentation techniques and evaluates their impact on model accuracy and *** demonstrate that augmentation techniques like Equalize significantly enhance the model's classification capabilities,achieving an F1-Score of 0.9869 for igneous rocks,0.9884 for metamorphic rocks,and 0.9929 for sedimentary rocks,representing improvements compared to the baseline original ***,the weighted average F1-Score across all classes and techniques is 0.9886,indicating an ***,methods like Distort lead to decreased accuracy and F1-Score,with an F1-Score of 0.949 for igneous rocks,0.954 for metamorphic rocks,and 0.9416 for sedimentary rocks,exacerbating the performance compared to the *** study underscores the practicality of image data augmentation in geological image classification and advocates for the adoption of DL methods in this domain for automation and improved *** findings of this study can benefit various fields,including remote sensing,mineral exploration,and environmental monitoring,by enhancing the accuracy of geological image analysis both for scientific research and industrial applications.

关键词： Deep learning(DL) Image analysis Image data augmentation Convolutional neural networks(CNNs) Geological image analysis Rock classification Rock thin section(RTS)images

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Gradient age-precipitation behavior induced by gradient nano-grain in Mg-Gd-Ag-Zr alloy

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Journal of Iron and Steel Research International 2025年第1期32卷 19-24页

作者： Bang-jun Li Jia-peng Sun Jing Han Guo-song Wu College of Materials Science and engineering Hohai UniversityNanjing 210024JiangsuChina school of Mechanical and Electrical engineering China University of Mining and TechnologyXuzhou 221116JiangsuChina

Gradient nano-grained structure is frequently engineered into metallic materials,including Mg alloys,to achieve superior combination of strength and ***,the influence of this microstructural feature on aging precipitation behavior remains inadequately *** this study,the age-precipitation behavior of a gradient nano-grained Mg-Gd-Ag-Zr alloy prepared via ultrasonic severe surface rolling was *** result indicates that the aging precipitation behavior exhibits a depth-dependent variation within this *** the nano-grained surface layer,hierarchicalβnano-precipitates are predominant,while at greater depths,the precipitates consist ofβnanoparticles located at grain boundaries,along with intragranularβ′andγ″*** formation ofβnano-precipitates deviates from the conventional precipitation behavior observed in Mg-Gd-Ag alloys,and is attributed to the high density of defects induced by the surface nano-grained *** finding advances our understanding of the precipitation behavior in the alloys with heterogeneous microstructure.

关键词： Mg alloy Gradient Precipitation Aging behavior Microstructure

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Experimental study on failure precursory characteristics and moisture content effect of pre-cracked rocks under graded cyclic loading and unloading

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International Journal of mining Science and Technology 2025年第2期35卷 249-264页

作者： Wei Zhang Dongxiao Zhang Weiyao Guo Baoliang Zhang school of Architecture and engineering Liaocheng UniversityLiaocheng 252000China College of Energy and mining engineering Shandong University of Science and TechnologyQingdao 266590China

It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock *** on digital speckle correlation(DSCM),acoustic emission(AE)and electromagnetic radiation(EMR),uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry,natural and saturated water content,to explore the fracture propagation,failure precursor characteristics and damage response mechanism under the influence of water content *** results show that with the increase of water content,the peak stress and crack initiation stress decrease gradually,and the decreases are 15.28%-21.11%and 17.64%-23.04%,*** peak strain and crack initiation strain increase gradually,and the increases are 19.85%-44.53%and 19.15%-41.94%,*** precracked rock with different water content is mainly characterized by tensile failure at different loading ***,with the increase of water content,the proportion of shear cracks gradually increases,while acoustic emission events gradually decrease,the dissipative energy and energy storage limits of the rock under peak load gradually decrease,and the charge signal increases significantly,which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.

关键词： Damage mechanisms Pre-cracked rocks Crack propagation Water-rock interaction Graded cyclic loading and unloading

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Application of a multi-monitoring system and its temperature correction

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Journal of Mountain Science 2025年第2期22卷 681-694页

作者： LIU Songyuan YANG Peixi HE ManChao TAO Zhigang State Key Laboratory for Tunnel engineering China University of Mining and Technology-BeijingBeijing 100083China school of Mechanics and Civil engineering China University of Mining and Technology-BeijingBeijing 100083China College of mining engineering North China University of Science and TechnologyTangshan 063210China

The Dazu Rock Carvings in Chongqing were inscribed on the World Heritage List in *** recent years,the Dazu Rock Carvings have faced environmental challenges such as geological forces,increased precipitation,pollution and tourism,which have led to rock deterioration and structural *** multi-source monitoring system for the protection of the rock carvings,based on the Internet of Things,includes Global Navigation Satellite System(GNSS)displacement monitoring,static level displacement monitoring,laser rangefinder displacement monitoring,roof pressure sensor monitoring and environmental damage *** paper analyses data from each sub-monitoring system within the multi-source monitoring system applied to Yuanjue Cave in the Dazu Rock ***,a correlation analysis between climate monitoring data and roof displacement data was carried out to assess the effect of *** on the results of the analysis,a temperature correction equation for the laser rangefinder was derived to improve the laser rangefinder displacement monitoring *** improved system was then used to monitor Cave 168,revealing the deformation and erosion patterns of the *** research results demonstrate that the multiparameter monitoring system is capable of accurately measuring and analyzing the stability of the Dazu stone carvings,as well as the effects of environmental conditions on *** use of the Internet of Things(IoT)and real-time data collection to monitor rock deformation and environmental conditions is an innovative application of technology in cultural heritage *** of the monitoring system and statistical correlation analysis of temperature and laser rangefinder data highlight the thoroughness of the methodology in this paper and its relevance to sustainable mountain *** the future,multi-source monitoring systems will have a broader application in the conservation of other UNESCO World Heritage Sites.

关键词： Multi-source Monitoring System Data Fitting Dazu Rock Carvings Rock Cave Protection

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Macro-and micro-mechanical response and damage mechanism of sandstone under high-temperature conditions

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International Journal of mining Science and Technology 2025年第2期35卷 265-274页

作者： Laiwei Wu Yanli Huang Junmeng Li Guiyuan Wang Yingshun Li Xiaotong Li Junzhi Chen Chuning Ji State Key Laboratory of Coal Exploration and Intelligent mining School of MinesChina University of Mining and TechnologyXuzhou 221116China Key Laboratory of Xinjiang Coal Resources Green mining Ministry of EducationXinjiang Institute of EngineeringUrumqi 830023China

The thermal effects of coal combustion considerably influence the physical and chemical properties,structural characteristics, and stability of rocks, posing a serious threat to the safety of coal mining operations. In this study, the impacts of temperature on the physical and chemical characteristics(i.e., mineral phase, microstructure, and mechanical strength) of sandstone were investigated by employing experimental methods, including microstructural analysis, uniaxial acoustic emission(AE), and nuclear magnetic resonance(NMR). The results indicate that temperature alters the mineral phase and the pore characteristics, and these two factors jointly affect the mechanical properties of sandstone. The influence of temperature on the mechanical strength of sandstone is categorized into low-temperature strengthening and high-temperature damage, with a threshold temperature identified at 600 ℃. The lowtemperature strengthening effect encompasses both pore strengthening and mineral phase strengthening, while the high-temperature damage effect primarily results from pore damage. As the experimental temperature rises, both the number of AE events and the AE energy transition from a surge in the postpeak failure stage to a stepwise increase during the loading process. This transition implies that the failure mode of the sandstone sample evolves from brittle failure to tensile failure.

关键词： Thermal effects Mineral phase Pore structure Acoustic emission energy Microscopic morphology

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Microstructure effect of mechanical and cracking behaviors on brittle rocks using image-based fast Fourier transform method

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Journal of Rock Mechanics and Geotechnical engineering 2025年第1期17卷 399-413页

作者： Mingyao Li Lei Peng Dejun Liu Jianping Zuo school of Mechanics and Civil engineering China University of Mining and TechnologyBeijing100083China State Key Laboratory for Tunnel engineering China University of Mining and TechnologyBeijing100083China

The internal microstructures of rock materials, including mineral heterogeneity and intrinsic microdefects, exert a significant influence on their nonlinear mechanical and cracking behaviors. It is of great significance to accurately characterize the actual microstructures and their influence on stress and damage evolution inside the rocks. In this study, an image-based fast Fourier transform (FFT) method is developed for reconstructing the actual rock microstructures by combining it with the digital image processing (DIP) technique. A series of experimental investigations were conducted to acquire information regarding the actual microstructure and the mechanical properties. Based on these experimental evidences, the processed microstructure information, in conjunction with the proposed micromechanical model, is incorporated into the numerical calculation. The proposed image-based FFT method was firstly validated through uniaxial compression tests. Subsequently, it was employed to predict and analyze the influence of microstructure on macroscopic mechanical behaviors, local stress distribution and the internal crack evolution process in brittle rocks. The distribution of feldspar is considerably more heterogeneous and scattered than that of quartz, which results in a greater propensity for the formation of cracks in feldspar. It is observed that initial cracks and new cracks, including intragranular and boundary ones, ultimately coalesce and connect as the primary through cracks, which are predominantly distributed along the boundary of the feldspar. This phenomenon is also predicted by the proposed numerical method. The results indicate that the proposed numerical method provides an effective approach for analyzing, understanding and predicting the nonlinear mechanical and cracking behaviors of brittle rocks by taking into account the actual microstructure characteristics.

关键词： Rock microstructure Cracking process Brittle rocks Fast Fourier transform(FFT) Digital image processing(DIP)

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