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Direct microwave leaching conditions of rare earth elements in fluorescent wastes

Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.Bilen B.Birol M.N.Saridede S.S.Kaplan M.S.Sonmez department of metallurgical and Materials engineering Yildiz Technical UniversityIstanbulTurkey department of Chemical engineering and Materials Science Stevens Institute of TechnologyNew JereyUSA department of metallurgical and Materials engineering Istanbul Technical UniversityIstanbulTurkey

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s *** can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth *** the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent *** the yields were *** the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were *** highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 *** energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction ***,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed ***,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elements(REEs) Direct microwave leaching Fluorescent waste Kinetic models Response surface method

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Revisiting the theoretical prediction of the explosive performance found by the Trauzl test

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Defence Technology（防务技术） 2024年第6期36卷 163-174页

作者： Ivana Dobrilovic Mario Dobrilovic Muhamed Suceska Faculty of mining Geology and Petroleum EngineeringDepartment of Mining Engineering and GeotechnicsUniversity of ZagrebPierottijeva 6Zagreb10000Croatia

The Trauzl lead block test allows the determination of the approximate performance of explosives in blasting applications by measuring the volume increase(expansion)that is produced by the detonation of an explosive charge in the cavity of a lead *** this paper,we reconsider the possibility of interpreting the Trauzl test results in terms of detonation parameters or *** detonation parameters used in the analysis are calculated using the thermochemical code EXPLO5,while the hydrocode AUTODYN is used to simulate the effect of explosive charge density and reaction rate on the results of the Trauzl *** increase in the volume of the lead block cavity was found to correlate best with the product of the detonation heat and the root of the volume of detonation *** simulation showed that the density of explosive charge and the rate of explosive decomposition affect the dynamics of the interaction of the detonation product and the lead block,and consequently the lead block cavity volume increase.

关键词： Trauzl lead block test Performance of explosives EXPLO5 AUTODYN Detonation heat

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Homovalent doping: An efficient strategy of the enhanced TiNb2O7 anode for lithium-ion batteries

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Green Energy & Environment 2024年第8期9卷 1257-1266页

作者： Xiaohe Jin Yirui Deng Han Tian Miaomiao Zhou Wenhao Tang Huiyou Dong Xinquan Zhang Ruiping Liu department of Materials Science and engineering China University of Mining & Technology (Beijing) department of Materials Science and engineering China University of Mining&Technology (Beijing)

The low energy density,unsatisfied cycling performance,potential safety issue and slow charging kinetics of the commercial lithium-ion batteries restrained their further application in the fields of fast charging and long-haul electric *** TiNb2O7（TNO） with the theoretical capacity of 387 mAh g-1has been proposed as a high-capacity anode materials to replace *** this work,homovalent doping strategy was used to enhance the electrochemical performance of Ti Nb2O7（TNO） by employing Zr to partial substitute Ti through solvothermal *** doping of Zr4+ions can enlarge the lattice structure without changing the chemical valence of the original elements,refine and homogenize the grains,improve the electrical conductivity,and accelerate the ion diffusion kinetics,and finally enhance the cycle and rate ***,Z0.05-TNO shows initial discharge capacity of as high as 312.2 mAh g-1at 1 C and 244.8 mAh g-1at 10 C,and still maintains a high specific capacity of 171.3 mAh g-1after 800 cycles at 10 *** study provides a new strategy for high-performance fastcharging energy storage electrodes.

关键词： Homovalent doping Zr 4+ TiNb 2 O 7 Microsphere Lithium-ion batteries

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Enhanced in-vitro degradation resistance and cytocompatibility of a thermomechanically processed novel Mg alloy:Insights into the role of microstructural attributes

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Journal of Magnesium and Alloys 2024年第2期12卷 700-725页

作者： Darothi Bairagi Santanu Mandal Mangal Roy Manas Paliwal Sumantra Mandal department of metallurgical and Materials engineering Indian Institute of TechnologyKharagpur 721302India

The role of microstructural features on in-vitro degradation and surface film development of a thermomechanically processed Mg-4Zn-0.5Ca-0.8Mn alloy has been investigated employing electrochemical studies,scanning electron microscopy and X-ray photoelectron *** specimen forged at 523 K temperature developed a coarse unimodal microstructure consisting of basal oriented grains,whereas the specimens forged at 623 K and 723 K temperatures exhibited bimodal microstructures containing randomly oriented fine grains and basal oriented coarse *** bimodal microstructures exerted higher resistance to corrosion compared to the unimodal microstructure in presence of a protective surface *** optimum size distribution of fine and coarse grains as well as the prevalence of basal oriented grains led to the lowest anodic current density in the specimen forged at 623 *** morphology of Ca_(2)Mg_(6)Zn_(3)precipitates governed the cathodic kinetics by controlling the anode to cathode surface area *** the specimen forged at 723 K comprised comparatively lower fraction of precipitates than at 623 K,the mesh-like precipitate morphology increased the effective cathodic surface area,leading to enhanced localised corrosion in the former *** microstructural features developed at 623 K forging temperature formed a well-protective surface film with lower Mg(OH)_(2)to MgO ratio,exhibiting distinctly high polarization resistance and superior cytocompatibility in terms of cell-proliferation and cell-differentiation.

关键词： Magnesium alloy Microstructure Corrosion Electrochemical impedance spectroscopy X-ray photoelectron spectroscopy Cytotoxicity

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Dielectric size optimization for high power density in large-scale triboelectric nanogenerators

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Nano Research 2024年第9期17卷 8455-8464页

作者： Abdulkerim Karabiber Ömer Dirik Feyyaz Koc Faruk Ozel department of Electrical and Electronics engineering Bingol UniversityBingol 12000Turkey department of metallurgical and Materials engineering Karamanoglu Mehmetbey UniversityKaraman 70200Turkey

Triboelectric nanogenerators(TENGs)have emerged as a promising technology to harvest electrical energy from natural motions such as human movement,wind,and water *** TENGs show significant potential in small-scale applications,developing large-scale TENGs capable of generating high power remains a significant *** factors that can affect the performance of large-scale TENGs are being investigated to overcome this challenge,including the size and configuration of dielectric *** study optimizes dielectrics regarding surface area,thickness,and multicell configuration to improve harvested electrical power density in large-scale *** the studies,glass fiber was used as the positive dielectric,and multipurpose white silicone was used as the negative dielectric because of their high tribo-potential,durability,and easy *** the size optimization phase,dielectric thicknesses and surface areas that provide the maximum power density were ***,horizontal and vertical multicell configurations were examined to efficiently integrate size-optimized *** results reveal that large-scale TENGs with vertical multicell configurations can achieve high and usable energy density for *** findings provide valuable insight into the development of large-scale TENGs with advanced power generation capabilities.

关键词： triboelectric nanogenerator dielectric layer size optimization multi-cell structure high power density

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Predicting uniaxial compressive strength of tuff after accelerated freeze-thaw testing: Comparative analysis of regression models and artificial neural networks

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Journal of Mountain Science 2024年第10期21卷 3521-3535页

作者： Ogün Ozan VAROL department of mining engineering Faculty of EngineeringVan Yuzuncu Yil UniversityVan 65080Türkiye

Ignimbrites have been widely used as building materials in many historical and touristic structures in the Kayseri region of Türkiye. Their diverse colours and textures make them a popular choice for modern construction as well. However, ignimbrites are particularly vulnerable to atmospheric conditions, such as freeze-thaw cycles, due to their high porosity, which is a result of their formation process. When water enters the pores of the ignimbrites, it can freeze during cold weather. As the water freezes and expands, it generates internal stress within the stone, causing micro-cracks to develop. Over time, repeated freeze-thaw (F-T) cycles lead to the growth of these micro-cracks into larger cracks, compromising the structural integrity of the ignimbrites and eventually making them unsuitable for use as building materials. The determination of the long-term F-T performance of ignimbrites can be established after long F-T experimental processes. Determining the long-term F-T performance of ignimbrites typically requires extensive experimental testing over prolonged freeze-thaw cycles. To streamline this process, developing accurate predictive equations becomes crucial. In this study, such equations were formulated using classical regression analyses and artificial neural networks (ANN) based on data obtained from these experiments, allowing for the prediction of the F-T performance of ignimbrites and other similar building stones without the need for lengthy testing. In this study, uniaxial compressive strength, ultrasonic propagation velocity, apparent porosity and mass loss of ignimbrites after long-term F-T were determined. Following the F-T cycles, the disintegration rate was evaluated using decay function approaches, while uniaxial compressive strength (UCS) values were predicted with minimal input parameters through both regression and ANN analyses. The ANN and regression models created for this purpose were first started with a single input value and then dev

关键词： Ignimbrite Uniaxial compressive strength Freeze-thaw Decay function Regression Artificial neural network

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High-resolution photogrammetry to measure physical aperture of two separated rock fracture surfaces

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Journal of Rock Mechanics and Geotechnical engineering 2024年第8期16卷 2922-2934页

作者： Masoud Torkan Mateusz Janiszewski Lauri Uotinen Alireza Baghbanan Mikael Rinne department of Civil engineering Aalto UniversityEspooFinland department of mining engineering Isfahan University of TechnologyIsfahanIran

Photogrammetry,reconstructing three-dimensional(3D)models from overlapping two-dimensional(2D)photos,finds application in rock mechanics and rock engineering to extract geometrical details of reconstructed objects,for example rock *** properties are important for determining the mechanical stability,permeability,strength,and shear behavior of the rock *** can be used to reconstruct detailed 3D models of two separated rock fracture surfaces to characterize fracture roughness and physical aperture,which controls the fluid flow,hydromechanical and shear behavior of the rock *** research aimed to determine the optimal number of scale bars required to produce high-precision 3D models of a fracture surface.A workflow has been developed to define the physical aperture of a fracture using *** blocks of Kuru granite(25 cm×25 cm×10 cm)with an artificially induced fracture,were *** scaling 3D models,321 markers were used as ground control points(GCPs)with predefined distances on each *** the samples were wellmatched in their original positions,the entire block was *** data of the GCPs were extracted from the 3D model of the *** half was surveyed separately and georeferenced by GCPs and merged into the same coordinate *** fracture surfaces were extracted from the 3D models and the vertical distance between the two surfaces was digitally calculated as physical *** assessment of the photogrammetric reconstruction showed a 20-30 mm digital control distance accuracy when compared to known distances defined between *** attain this accuracy,the study found that at least 200 scale bars were ***,photogrammetry was employed to measure changes in aperture under normal *** results obtained from this approach were found to be in good agreement with those obtained using linear variable displacement transducers(LVDTs),with differences ran

关键词： Photogrammetry Physical aperture Rock fracture Predefined distances Markers

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Advancing respirable coal mine dust source apportionment:a preliminary laboratory exploration of optical microscopy as a novel monitoring tool

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International Journal of Coal Science & Technology 2024年第2期11卷 222-233页

作者： Nestor Santa Emily Sarver department of mining and Minerals engineering Virginia TechBlacksburgVA 24061USA

Exposure to respirable coal mine dust(RCMD)can cause chronic and debilitating lung ***-time monitoring capabilities are sought which can enable a better understanding of dust components and *** many underground mines,RCMD includes three primary components which can be loosely associated with three major dust sources:coal dust from the coal seam itself,silicates from the surrounding rock strata,and carbonates from the inert‘rock dust’products that are applied to mitigate explosion hazards.A monitor which can reliably partition RCMD between these three components could thus allow source *** tracking silicates,specifically,could be valuable since the most serious health risks are typically associated with this component-particularly if abundant in crystalline *** a monitoring concept based on field microscopy,and following up on prior research using polarized light,the aim of the current study was to build and test a model to classify respirable-sized particles as either coal,silicates,or *** model development,composite dust samples were generated in the laboratory by successively depositing dust from high-purity materials onto a sticky transparent substrate,and imaging after each deposition event such that the identity of each particle was known a *** testing followed a similar approach,except that real geologic materials were used as the source for each dust *** showed that the model had an overall accuracy of 86.5%,indicating that a field-microscopy based moni-tor could support RCMD source apportionment and silicates tracking in some coal mines.

关键词： Polarized light microscopy Image processing Dust monitoring Respirable silica Coal mining

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Recycling arsenic-containing bio-leaching residue after thermal treatment in cemented paste backfill:Structure modification,binder properties and environmental assessment

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2136-2147页

作者： Dengfeng Zhao Shiyu Zhang Yingliang Zhao department of mining engineering Lyuliang UniversityLvliang 033000China School of Civil and Environmental engineering University of Science and Technology BeijingBeijing 100083China School of mining engineering Taiyuan University of TechnologyTaiyuan 030024China department of Civil and Environmental engineering The Hong Kong Polytechnic UniversityHong Kong 00852China

The substantial arsenic(As)content present in arsenic-containing bio-leaching residue(ABR)presents noteworthy environ-mental challenges attributable to its inherent instability and susceptibility to *** its elevated calcium sulfate content,ABR exhibits considerable promise for industrial *** study delved into the feasibility of utilizing ABR as a source of sulfates for producing super sulfated cement(SSC),offering an innovative binder for cemented paste backfill(CPB).Thermal treatment at varying temperatures of 150,350,600,and 800℃ was employed to modify ABR’s *** investigation encompassed the examination of phase transformations and alterations in the chemical composition of As within ***,the hydration characteristics of SSC utilizing ABR,with or without thermal treatment,were studied,encompassing reaction kinetics,setting time,strength development,and *** findings revealed that thermal treatment changed the calcium sulfate structure in ABR,consequently impacting the resultant sample ***,calcination at 600℃ demonstrated optimal modification effects on both early and long-term strength *** enhanced performance can be attributed to the augmented formation of reaction products and a densified ***,the thermal treatment elicited modifications in the chemical As fractions within ABR,with limited impact on the As immobilization capacity of the prepared binders.

关键词： cemented paste backfill bio-leaching residue arsenic immobilization binder hydration calcination

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Synergistic enhancement of photocatalytic and antimicrobial efficacy of nitrogen and erbium co-doped ZnO nanoparticles

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Journal of Rare Earths 2024年第5期42卷 859-868,I0002页

作者： Sudipta Mondal Moniruzzaman Jamal Sikder Ashikuzzaman Ayon Md Jannatul Ferdous Anik Md Muktadir Billah department of Materials and metallurgical engineering Bangladesh University of Engineering and TechnologyDhaka1000Bangladesh School of Materials engineering Purdue UniversityWest LafayetteIN47907USA department of Materials Science and engineering University of CaliforniaBerkeleyCA94720USA department of Materials Science and engineering Northwestern UniversityEvanstonI28USA

Using the chemical co-precipitation approach,a series of nitrogen(N) and erbium(Er) co-doped ZnO nanoparticles(NPs) was effectively synthesized to enhance the photocatalytic and antibacterial *** characterization techniques,including X-ray diffraction(XRD),X-ray photoelectron spectro scopy(XPS),scanning electron microscopy(SEM),UV-vis,and photoluminescence(PL) spectroscopy,were carried out to validate the evaluated photocatalytic and antibacterial *** analysis confirms the pure wurtzite ZnO phase without the presence of any secondary *** analysis confirms the succe ssful incorporation of nitrogen and erbium into the ZnO *** optical bandgap of ZnO calculated from UV-vis spectroscopy shows a redshift after Er-N co-doping,with the lowest bandgap of 3.215 eV calculated for Zn_(0.97)Er_(0.03)N_(0.01)O_(0.99) *** images demonstrate the formation of nanorods after N-Er co-doping,followed by gradually increase d rod diameter and length after N-Er ***,the photocatalytic activities of ZnO samples we re measured by their ability to facilitate the photodegradation of Rhodamine B under UV *** with 1 mol% N doping exhibits 88% photodegradation of RhB under UV light within 360 min,and the photodegradation and antibacterial activity are greatly improved with Er *** fact,3 mol% Er-1 mol% N doped ZnO NPs demonstrate the highest photocatalytic activity,with approximately 96% degradation after 360 min,as well as superior antibacterial activity against Staphylococcus aureus(Gram-positive bacteria) and Pseudomonas aeruginosa(Gram-negative bacteria) with the highest zone of inhibition(ZOI) of 16 nm,due to nanorod formation,increased reactive oxygen species(ROS),and decreased electron-hole recombination,as validated by SEM,XPS,and PL spectroscopy.

关键词： Chemical co-precipitation Co-doping Bandgap Photocatalysis Rare earths Antimicrobial

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