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Research on new beneficiation process of low-grade magnesite using vertical roller mill

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International Journal of Minerals,Metallurgy and Materials 2020年第4期27卷 432-442页

作者： chuang Li chuan-yao sun Yu-lian Wang Ya-feng Fu Peng-yun Xu Wan-zhong Yin School of Resources and Civil Engineering Northeastern UniversityShenyang 110819China State Key Laboratory of Mineral Processing Beijing 102628China National Engineering Research Center of WEEE Recycling Engineering Jingmen 448124China School of Materials Science and Engineering Shenyang Ligong UniversityShenyang 110159China College of Zijin Mining Fuzhou UniversityFuzhou 350108China

We investigated whether the vertical roller mill can be efficiently used in the beneficiation of low-grade magnesite and whether it can improve upon the separation indices achieved by the ball *** conducted experiments involving the reverse flotation and positive flotation of low-grade magnesite to determine the optimum process parameters,and then performed closed-circuit beneficiation experiments using the vertical roller mill and ball *** results show that the optimum process parameters for the vertical roller mill are as follows:a grinding fineness of 81.6wt%of particles less than 0.074 mm,a dodecyl amine(DDA)dosage in magnesite reverse flotation of 100 g·t?1,and dosages of Na2CO3,(NaPO3)6,and NaOL in the positive flotation section of 1000,100,and 1000 g·t?1,*** with the ball mill,the use of the vertical roller mill in the beneficiation of low-grade magnesite resulted in a 1.28%increase in the concentrate grade of MgO and a 5.88%increase in the recovery of *** results of our causation mechanism analysis show that a higher specific surface area and greater surface roughness are the main reasons for the better flotation performance of particles ground by the vertical roller mill in the beneficiation of lowgrade magnesite.

关键词： low-grade magnesite vertical roller mill reverse flotation positive flotation new beneficiation process

Selective flotation separation of andalusite and quartz and its mechanism

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International Journal of Minerals,Metallurgy and Materials 2019年第9期26卷 1059-1068页

作者： Yan-ping Niu chuan-yao sun Wan-zhong Yin Xing-rong Zhang Hong-feng Xu Xu Zhang College of Resources and Civil Engineering Northeastern UniversityShenyang 110000China State Key Laboratory of Mineral Processing BGRIMM Technology GroupBeijing 100160China The Research Center of Experimental Testing for Geology and Minerals in Heilongjiang Province Harbin 150000China Heilongjiang Mining Group Co. Ltd. Harbin 150000China

The separation of andalusite and quartz was investigated in the sodium oleate flotation system, and its mechanism was studied by solution chemical calculation, zeta-potential tests, Fourier transform infrared spectroscopic(FTIR), and X-ray photoelectron spectroscopic(XPS). The flotation tests results show that FeCl3·6H2O has a strong activation effect on andalusite and quartz and citric acid has a strong inhibitory effect on activated quartz, thus increasing the floatability difference between quartz and andalusite when the pulp p H is approximately 8. The FTIR, Zeta potential, and XPS analyses combined with the chemical calculation of flotation reagent solutions demonstrate that Fe forms hydroxide precipitates on the surface of andalusite and quartz and that oleate anions and metal ions adsorb onto the surface of the minerals. The elements Al and Fe can be chemically reacted. The anions in citric acid have different degrees of dissolution of Fe on the andalusite and quartz surfaces, thereby selectively eliminating the activation of the elemental Fe on andalusite and quartz and increasing the floatability of andalusite, leading to a better separation effect between andalusite and quartz.

关键词： andalusite quartz flotation mechanism zeta potential Fourier infrared spectrum analysis X-ray photoelectron energy spectrum analysis

New insights into the flotation responses of brucite and serpentine for different conditioning times: Surface dissolution behavior

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International Journal of Minerals,Metallurgy and Materials 2021年第12期28卷 1898-1907页

作者： Ya-feng Fu Wan-zhong Yin Xian-shu Dong chuan-yao sun Bin Yang Jin yao Hong-liang Li chuang Li Hyunjung Kim College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Resources&Civil Engineering Northeastern UniversityShenyang 110819China State Key Laboratory of Mineral Processing Beijing 102628China Department of Chemical and Materials Engineering University of AlbertaEdmontonAlberta T6G 2V4Canada Department of Mineral Resources and Energy Engineering Jeonbuk National UniversityBaekje-daeroDeokjin-guJeonju-siJeollabuk-do561-756Republic of Korea

The inadvertent dissolution of gangue minerals is frequently detrimental to the flotation of valuable *** investigated the effect of conditioning time on the separation of brucite and serpentine by *** analyzing the Mg2+concentration,relative element content,and pulp viscosity,we studied the effect of mineral dissolution on brucite *** results of artificially mixed mineral flotation tests(with-10μm serpentine)showed that by extending the conditioning time from 60 to 360 s,a large amount of Mg2+on the mineral surface gradually dissolved into the pulp,resulting in a decreased brucite recovery(from 83.83%to 76.79%)and an increased recovery of serpentine from 52.12%to 64.03%.To analyze the agglomeration behavior of brucite and serpentine,we used scanning electron microscopy,which clearly showed the different adhesion behaviors of different conditioning ***,the total interaction energy,as determined based on the extended DLVO(Derjaguin-Landau-Verwey-Overbeek)theory,also supports the conclusion that the gravitational force between brucite and serpentine increases significantly with increased conditioning time.

关键词： behavior insight viscosity

Improved flotation performance of hematite fines using citric acid as a dispersant

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International Journal of Minerals,Metallurgy and Materials 2016年第10期23卷 1119-1125页

作者： Xi-mei Luo Wan-zhong Yin chuan-yao sun Nai-ling Wang Ying-qiang Ma Yun-fan Wang State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and Technology Kunming 650093 China Faculty of Land and Resource Engineering Kunming University of Science and Technology Kunming 650093 China College of Zijin Mining Fuzhou University Fuzhou 350116 China College of Resources and Civil Engineering Northeastem University Shenyang 110819 China Beijing General Research Institute of Mining and Metallurgy Beijing 100044 China Faculty of Minerals Processing and Bioengineering Central South University Changsha 410083 China

In this study, citric acid was used as a dispersant to improve the flotation performance of hematite fines. The effect and mechanism of citric acid on the reverse flotation of hematite fines were investigated by flotation tests, sedimentation experiments, scanning electron microscopy（SEM）, zeta-potential measurements, and X-ray photoelectron spectroscopy（XPS）. The results of SEM analysis and flotation tests reveal that a strong heterocoagulation in the form of slime coating or coagulation in hematite fine slurry affects the beneficiation of hematite ores by froth flotation. The addition of a small amount of citric acid（less than 300 g/t） favorably affects the reverse flotation of hematite fines by improving particle dispersion. The results of sedimentation experiments, zeta-potential measurements, and XPS measurements demonstrate that citric acid adsorbs onto hematite and quartz surfaces via hydrogen bonding, thereby reducing the zeta potentials of mineral surfaces, strengthening the electrical double-layer repulsion between mineral particles, and dispersing the pulp particles.

关键词： hematite citric acid dispersion flotation hydrogen bonding

Synthesis of novel thionocarbamate for copper-sulfur flotation separation and its adsorption mechanism

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Transactions of Nonferrous Metals Society of China 2022年第8期32卷 2709-2718页

作者： Fei CAO De-si sun Xian-hui QIU De-zhi ZHOU Xing-rong ZHANG chuan-yao sun School of Chemistry and Chemical Engineering Jiujiang UniversityJiujiang 332005China State Key Laboratory of Mineral Processing BGRIMM Technology GroupBeijing 102600China School of Resource and Environment Engineering Jiangxi University of Science and TechnologyGanzhou 341000China State Key Laboratory of Comprehensive Utilization of Low-Grade Refractory Gold Ores(Zijin Mining Group Co. Ltd.)Shanghang 364200China

As a novel collector, O-isopropyl-N,N-diethyl thionocarbamate(IPDTC) was designed and synthesized for copper-sulfur flotation separation. Density functional theory calculations were performed to investigate the electronic structures of IPDTC. The results showed that IPDTC had higher energy of the highest occupied molecular orbital but lower electronegativity than O-isopropyl-N-ethyl thionocarbamate(Z-200). It was predicted that IPDTC had strong collection ability according to the reaction energy criteria. Flotation results demonstrated that the collecting ability of IPDTC to chalcopyrite and pyrite was stronger than that of Z-200. Then, the flotation mechanism was analyzed by measurements of surface tension, adsorption capacity, XPS, FTIR and zeta potential. These results indicated that IPDTC could reduce the solution surface tension. The adsorption capacity of IPDTC on chalcopyrite was higher than that on pyrite, consistent with the results of the flotation tests. FTIR, zeta potential and XPS results also demonstrated that IPDTC was strongly absorbed on the chalcopyrite surface by formation of Cu—S—C bonds, but showed a weak affinity on the pyrite surface.

关键词： O-isopropyl-N N-diethyl thionocarbamate adsorption mechanism chalcopyrite pyrite density functional theory

Limits of Uneven Battery Power in Modular Multilevel Converter-based Battery Energy Storage Systems

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 686-695页

作者： yao Pan Xiaofeng sun Wei Zhao Xin Li yao Cai Institute of Electrical Engineering Yanshan UniversityQinhuangdao 066004China

For modular multilevel converter-based battery energy storage systems (MMC-BESS), uneven power among batteries of SMs will be deduced by battery aging, battery fault, etc., which will degrade performance and even lead to system failure. For maintaining the balance of capacitor voltage, this paper analyzes the limits of the uneven power of batteries, which are presented as the current limits in this paper. According to analysis, an analytical method is proposed that only the dc and fundamental frequency components of the arm current are used to calculate current limits. With the current limits it is able to evaluate the reasonability of power distribution among batteries. Meanwhile, increase of fundamental frequency component will enhance the current limits, and the dc component determines the size relationship between the absolute values of the upper and lower current limits. Finally, simulation model and experiment prototype are built for verifying the theoretical analysis and current limits calculation method, and satisfactory results are provided.

关键词： Arm current balance of capacitor voltage current limits MMC-BESS uneven power

Exploring luminescence quenching on lanthanide-doped nanoparticles through changing the spatial distribution of sensitizer and activator

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Nano Research 2024年第5期17卷 4517-4524页

作者： Jiwei Li yao Xie Renrui sun Junxun Zhou Lining sun Department of Chemistry College of SciencesShanghai UniversityShanghai 200444China Department of Physics College of SciencesShanghai UniversityShanghai 200444China School of Medicine Shanghai UniversityShanghai 200444China

Luminescence quench is common in overdoped upconversion *** methods have been proposed to counteract the adverse effects of concentration quenching on luminescence,but in upconversion nanoparticles that are highly doped with both sensitizers and activators,the factors that contribute to the diminishing of the emission cannot be summarized by a single ***,a core-shell design is used to spatially separate the sensitizer(Yb^(3+))and activator(Er^(3+))and to modulate the emission by changes in the distribution position as well as the concentration of the dopant ions in order to probe the factors affecting the *** the sensitizer ions are located in the core,the luminescence intensity of the nanoparticles is significantly weaker than that of the other distribution,which implies that the effect of sensitizer and activator on luminescence in the highly doped state has a different and more complex *** intensity of the emission is more affected by Yb^(3+)than Er^(3+),which includes not only the self-quenching of Yb^(3+),but also the dominance in the Yb^(3+)-Er^(3+)*** this finding may provide new ideas for revealing the reasons for the diminished luminescence of highly doped upconversion nanoparticles and thus for enhancing luminescence.

关键词： upconversion luminescence lanthanide ion core-shell nanoparticles concentration quenching cross-relaxation

Piezotronic neuromorphic devices:principle,manufacture,and applications

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International Journal of Extreme Manufacturing 2024年第3期6卷 363-385页

作者： Xiangde Lin Zhenyu Feng yao Xiong Wenwen sun Wanchen yao Yichen Wei Zhong Lin Wang Qijun sun Department of Research Shanghai University of Medicine and Health Sciences Affiliated Zhoupu HospitalShanghai 201318People’s Republic of China Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400People’s Republic of China Center on Nanoenergy Research School of Chemistry and Chemical EngineeringGuangxi UniversityNanning 530004People’s Republic of China Shandong Zhongke Naneng Energy Technology Co. LtdDongying 257061People’s Republic of China Georgia Institute of Technology AtlantaGA 30332-0245United States of America

With the arrival of the era of artificial intelligence(AI)and big data,the explosive growth of data has raised higher demands on computer hardware and *** techniques inspired by biological nervous systems are expected to be one of the approaches to breaking the von Neumann *** neuromorphic devices modulate electrical transport characteristics by piezopotential and directly associate external mechanical motion with electrical output signals in an active manner,with the capability to sense/store/process information of external *** this review,we have presented the piezotronic neuromorphic devices(which are classified into strain-gated piezotronic transistors and piezoelectric nanogenerator-gated field effect transistors based on device structure)and discussed their operating mechanisms and related manufacture ***,we summarized the research progress of piezotronic neuromorphic devices in recent years and provided a detailed discussion on multifunctional applications,including bionic sensing,information storage,logic computing,and electrical/optical artificial ***,in the context of future development,challenges,and perspectives,we have discussed how to modulate novel neuromorphic devices with piezotronic effects more *** is believed that the piezotronic neuromorphic devices have great potential for the next generation of interactive sensation/memory/computation to facilitate the development of the Internet of Things,AI,biomedical engineering,etc.

关键词： piezotronics neuromorphic devices strain-gated transistors piezoelectric nanogenerators synaptic transistors

A noval iron-capturing nanocomposites against biofilms for disrupting bacterial nutritional balance

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Science China Chemistry 2024年第6期67卷 1760-1761页

作者： Jinying Lin Qihang Ding yao sun Department of Oral Implantology Jilin Provincial Key Laboratory of Tooth Development and Bone RemodelingSchool of StomatologyJilin UniversityChangchun130021China Department of Chemistry Korea UniversitySeoul02841Korea National Key Laboratory of Green Pesticide International Joint Research Center for Intelligent Biosensor Technology and HealthCollege of ChemistryCentral China Normal UniversityWuhan430079China

Currently,the escalating crisis of bacterial infections and antibiotic resistance poses a significant global public health challenge[1-3].This situation has driven the search for novel antimicrobial ***,a crucial micr... 详细信息

关键词： metabolism resistance balance