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Effect of different operation conditions on PCDD/F inhibition by ammonium dihydrogen phosphate:concentrations,distributions and mechanisms

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Waste Disposal and Sustainable Energy 2024年第1期6卷 11-23页

作者： Jiayao Wu Weican Xiang Xiaoxiao Wang Wenlong Song Yuxuan Ying Xiaoqing Lin Xiaodong Li State Key Laboratory of Clean Energy Utilization National Engineering Laboratory of Waste Incineration Technology and EquipmentInstitute of Thermal Power Engineering of Zhejiang UniversityHangzhou310027ZhejiangChina

Phosphorus-containing compounds are considered as the potential alternatives of traditional inhibitors for suppressing the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs),but the suppression characteristics are scarcely studied.In this study,ammonium dihydrogen phosphate(ADP)was selected as the inhibitor to inhibit the PCDD/F formation via de novo synthesis at 350℃.The influence of oxygen content and addition method on PCDD/F inhibition was systematically investigated by means of statistical analysis and morphological characterization.The results showed that oxygen enhanced the formation of PCDD/Fs from 1470 ng g^(−1)(9.78 ng I-TEQ g^(−1))to 2110 ng g^(−1)(14.8 ng I-TEQ g^(−1)).ADP significantly inhibited the PCDD/F formation,with inhibition efficiencies ranging from 82.0%to 97.7%.Herein,a higher oxygen content and the premixed way intensified the suppression effect.Dibenzo-p-dioxin(DD)/dibenzofuran(DF)chlorination was proven to be effectively suppressed while chlorophenol(CP)route was not obviously influenced.With the addition of ADP,Cl source was significantly reduced and the formation of organic Cl was effectively inhibited.Also,it decreased the proportion of C–O/C=N and C=O,revealing the efficient inhibition of carbon oxidation.Meanwhile,the formation of copper phosphate and copper pyrophosphate was observed in XPS(X-ray photoelectron spectroscopy)spectra,indicating that the catalytic metal Cu was chelated and passivated by ADP.The premixed way had a better effect on reducing Cl resources,inhibiting oxidation and chelating metals,due to the direct contact with inhibitor.However,the separation method could only depend on the decomposed gases,resulting in a lower inhibition efficiency.

关键词： Ammonium dihydrogen phosphate Polychlorinated dibenzo-p-dioxins and dibenzofuran inhibition oxygen content Adding way Mechanisms

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Effect of overheating-induced minor addition on Zr-based metallic glasses

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Chinese Physics B 2024年第3期33卷 118-125页

作者：杨福薄振兴黄瑶王雨田孙博阳鲁振孙保安柳延辉汪卫华潘明祥 Institute of Physics Chinese Academy of SciencesBeijing 100190China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China

Melt treatment is well known to have an important influence on the properties of metallic glasses(MGs).However,for the MGs quenched from different melt temperatures with a quartz tube,the underlying physical origin responsible for the variation of properties remains poorly understood.In the present work,we systematically studied the influence of melt treatment on the thermal properties of a Zr50Cu36Al14 glass-forming alloy and unveiled the microscopic origins.Specifically,we quenched the melt at different temperatures ranging from 1.1Tl to 1.5Tl(Tl is the liquidus temperature)to obtain melt-spun MG ribbons and investigated the variation of thermal properties of the MGs upon heating.We found that glass transition temperature,Tg,increases by as much as 36 K,and the supercooled liquid region disappears in the curve of differential scanning calorimetry when the melt is quenched at a high temperature up to 1.5Tl.The careful chemical analyses indicate that the change in glass transition behavior originates from the incorporation of oxygen and silicon in the molten alloys.The incorporated oxygen and silicon can both enhance the interactions between atoms,which renders the cooperative rearrangements of atoms difficult,and thus enhances the kinetic stability of the MGs.

关键词： metallic glass thermal properties melt treatment overheating oxygen content

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Effect of surface Nd-rich phase and oxygen content of melt-spun flakes on formation of coarse grains in hot-pressed Nd-Fe-B magnet

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Journal of Rare Earths 2021年第11期39卷 1389-1395,I0003页

作者： Yeyuan Du Wenzong Yin Renjie Chen Xu Tang Jinyun Ju Bin Chen Longquan Hou Aru Yan Jianhui Yuan School of Materials Engineering Shanghai Collaborative Innovation Center of Laser Advanced Manufacturing TechnologyShanghai University of Engineering ScienceShanghai 201620China Key Laboratory of Magnetic Materials and Devices.Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China

Nd-Fe-B hot-pressed(HP) magnet prepared from melt-spun MQU-F flakes features coarse grains(CG)with the average size of both 200 nm(CGS) and 700 nm(CGL) at flake boundary.The grain growth at the flake boundary of Nd2 Fe14B/α-Fe composite HP magnet before and after diffusion of low-melting-point Pr82Cu18 phase was investigated,revealing the indispensable role of surface RE-rich phase of meltspun flakes in the formation of CG in HP magnet.The dominant role of surface oxygen content of melt-spun flakes in the formation of CGL has been clarified with etching method.The HP magnet prepared from the etched flakes with dramatically decreased oxygen content exhibits the CG regions merely with homoge neous equiaxed CGS at flake boundary.Consequently,the coercivity(μ0 Hc) shows significant increase while remanent magnetization(μ0 Mr) inappreciable change.Further investigation with sieving method reveals the elimination of CGL via removal of the fine Nd-Fe-B flakes smaller than 54 μm due to their much higher oxygen content,confirming the dominant role of oxygen content in the formation of CGL.The quantitative analysis on the magnetic properties of the above HP magnets reveals the monotonic increase of coercivity(μ0 Hc) and negligible change of remanent magnetization(μ0 Mr) with decreased oxygen contents of Nd-Fe-B flakes.The maximum value of coercivity(μ0 Hc) increases from2.26 to 2.47 T as the oxygen content decreases from 0.1692 wt% to 0.079 wt%.

关键词： Coarse grain Hot pressing Nd-Fe-B oxygen content Nd-rich phase Rare earths

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Influence of refining process and utilization of different slags on inclusions, titanium yield and total oxygen content of Ti-stabilized 321 stainless steel

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Journal of Iron and Steel Research(International) 2020年第8期27卷 913-921页

作者： Xing-run Chen Guo-guang Cheng Yu-yang Hou Jing-yu Li Ji-xiang Pan State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Hongxing Iron and Steel Co. Ltd.Jiuquan Iron and Steel Group CorporationJiayuguan 735100GansuChina

Ti-stabilized 321 stainless steel was prepared using an electric arc furnace, argon oxygen decarburization (AOD) furnace, ladle furnace (LF), and continuous casting processes. In addition, the effect of refining process and utilization of different slags on the evolution of inclusions, titanium yield, and oxygen content was systematically investigated by experimental and thermodynamic analysis. The results reveal that the total oxygen content (TO) and inclusion density decreased during the refining process. The spherical CaO–SiO2–Al2O3–MgO inclusions existed in the 321 stainless steel after the AOD process. Moreover, prior to the Ti addition, the spherical CaO–Al2O3–MgO–SiO2 inclusions were observed during LF refining pro-cess. However, Ti addition resulted in multilayer CaO–Al2O3–MgO–TiOx inclusions. Two different samples were prepared by conventional CaO–Al2O3-based slag (Heat-1) and -TiO2-rich CaO–Al2O3-based slag (Heat-2). The statistical analysis revealed that the density of inclusions and the -TiOx content in CaO–Al2O3–MgO–TiOx inclusions found in Heat-2 sample are much lower than those in the Heat-1 sample. Furthermore, the TO content and Ti yield during the LF refining process were controlled by using -TiO2-rich calcium aluminate synthetic slag. These results were consistent with the ion–molecule coexist-ence theory and FactSage?7.2 software calculations. When -TiO2-rich CaO–Al2O3-based slag was used, the -TiO2 activity of the slag increased, and the equilibrium oxygen content significantly decreased from the AOD to LF processes. Therefore, the higher -TiO2 activity of slag and lower equilibrium oxygen content suppressed the undesirable reactions between Ti and O.

关键词： 321 Austenitic stainless steel oxygen content Inclusion TiO2-rich CaO–Al2O3-based slag Ladle furnace(LF)refining process Ion–molecule coexistence theory

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Changes of oxygen content in Molten TiAl Alloys as a Function of Superheat during Vacuum Induction Melting

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Journal of Materials Science & Technology 2010年第10期26卷 900-903页

作者： Bo Chen,Yingche Ma,Ming Gao and Kui Liu Institute of Metal Research,Chinese Academy of sciences,Shenyang 110016,China Institute of Metal Research Chinese Academy of sciences Shenyang 110016 China

Experimental studies on the melting process of titanium aluminum alloy have been pursued from the viewpoint of contamination.TiAl alloys were prepared with vacuum induction melting （VIM） in calcia crucibles at 1873 K and 1923 K in order to determine the behavior of the oxygen content as a function of temperature,time and frequency of power.The experiment results showed that alloys were uncontaminated except for the increasing of oxygen content which was introduced from the reaction CaO（s）=Ca（in TiAl）＋O（in TiAl）,and the standard Gibbs energy of the reaction was determined to be △G0 =274000 102.8T（J/mol）.oxygen content increased slowly with the melting time by about 50×10-6 wt pct/min,and decreased with induction melting frequency.Lower superheat and higher melting frequency can be used to reduce oxygen content increasing rate.

关键词： TiAl alloys Induction melting Calcia crucible oxygen content

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Effect of oxygen content on dielectric characteristics of Cr-doped LaTiO_x

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Chinese Physics B 2018年第5期27卷 492-499页

作者：马铭陈彦崔益民 School of Aeronautic Science and Engineering Beihang University School of Physics Beihang University

The ceramics La0.85Cr0.15TiOx and La0.7Cr0.3TiOx are prepared by conventional solid-state reaction method. The dielectric properties of Cr-doped La TiOx as a function of frequency（0.1 k Hz ≤ f ≤ 1 MHz） and temperature（77 K ≤ T ≤360 K） are studied. The blocks are then annealed in a flowing O2 or Ar/H2 to convert their oxygen content and the tests mentioned above are performed. The highly oxygenated samples exhibit extremely high low-frequency dielectric constants at room temperature（～10^6）. The results show that the oxygen stoichiometry could significantly influence the dielectric properties of Cr-doped LaTiOx.

关键词： oxygen content dielectric characteristics LaTiOx

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Investigation on dependence of BiFeO_3 dielectric property on oxygen content

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Chinese Physics B 2010年第7期19卷 555-558页

作者：娄艳辉宋桂林常方高王照奎 Department of Physics Henan Normal University

The influence of oxygen content on the dielectric property of BiFeO3 ceramics is studied by experiment and firstprinciples calculation. The experimental result demonstrates that the dielectric constant of BiFeO3 is strongly dependent on introduced oxygen and oxygen vacancies. By comparison with BiFeO3, the introduced oxygen and oxygen vacancies can lead to a reduction in dielectric constant of BiFeO5 at a lower frequency. The first-principles calculation also shows a similar result when photon energy is in a range of 2.0-4.1 eV. A likely explanation is that this oxygen content dependence may be ascribed to the distortion of Fe-O octahedron structure due to oxygen vacancies or excess oxygen ions in the crystal structure of BiFeO3.

关键词： BiFeO3 dielectric property oxygen content

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Study on oxygen content, Inclusions and Fatigue Properties of Bearing Steels Produced by Different Processes

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Journal of University of Science and Technology Beijing 2001年第1期8卷 25-27页

作者： Deguang Zhou Jie Fu Xichun Chen Jing Li Metallurgy School, University of Science and Technology-Beijing, Beijing 100083, China Metallurgy School Univ. of Science/Technology-Biejing Beijing 100083 China

The metallurgical properties and fatigue life of bearing steel processed by electric furnace (EAF), ladle refining (LF-VD), continous casting (CC) and electroslag remelting (ESR) have been investigated. The main results obtained are as follows: (1) Due to low oxygen content and dispersion inclusions in steel, the fatigue Life of LF-VD-IC or CC is three times as high as that of EAF steel; (2) The oxygen content in steel produced by CC process is about 9.0x10(-6), the carbon segregation (C/C(0)) is from 0.92 to 1.10 and the fatigue life of CC steel is equal to that of ladle refining ingot casting steel; (3) Although the amount of inclusion and oxygen in ESR steel is higher than that of LF-VD-IC or CC steel, the fatigue life of ESR steel is higher than that of the latter because of its fine and well dispersed inclusions.

关键词： bearing steel ladle refining continuous casting electroslag remelting oxygen content inclusion fatigue life

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Synthesis of KNiF_3 with Lower oxygen content by Refluxing Method

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Chemical Research in Chinese Universities 2010年第2期26卷 178-180页

作者： SHEN Hai-yun YANG Qiu-hua ZHAO Shao-jing WANG Dan Department of Chemistry School of Science Tianjin University Tianjin 300072 P. R. China

The complex fluoride, KNiF3, with perovskite structure was synthesized by refluxing KF and Ni（NO3）2·6H20 in ethanediol. The samples were characterized by X-ray diffraction（XRD）, transmission electron microscopy（TEM）, X-ray photoelectron spectroscopy（XPS）, and ultraviolet-visible diffuse reflectance speetroseopy（UV-Vis DRS）. The results indicate that the mean diameter of KNiF3 particles is about 30-60 nm and the oxygen content in the samples is ≤5%. The prepared KNiF3 shows obvious absorption peaks at 400-830 nm.

关键词： KNiF3 Refluxing method oxygen content

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How to improve superlubricity performance of diketone at steel interface:Effects of oxygen gas

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Friction 2023年第6期11卷 927-937页

作者： Yuanyuan JIANG Lei CHEN Chen XIAO Shumin ZHANG Chenhui ZHANG Ningning ZHOU Tao QIN Linmao QIAN Jiyang ZHANG Tribology Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu610031China Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province Southwest Jiaotong UniversityChengdu610031China State Key Laboratory of Tribology Tsinghua UniversityBeijing100084China Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing100094China

Achievement of steady and reliable super-low friction at the steel/steel contact interface,one of the most tribological systems applied for mechanical moving parts,is of importance for prolonging machine lifetime and reducing energy consumption.Here we reported that the superlubricity performance of the steel/steel sliding interface lubricated with tiny amounts of diketone solution strongly depends on the oxygen content in surrounding environment.The increase of oxygen not only significantly shortens the initial running-in time but also further reduces the stable coefficient of friction in superlubricity stage due to the enhancement of tribochemical reactions.On the one hand,more severe oxidation wear occurring at higher oxygen content facilitates material removal of the contact interface,lowering the contact pressure and the corresponding initial friction.On the other hand,the growth of iron ions during the shear process in high oxygen environment promotes the formation of chelate which acted as an effective lubricated film chemisorbed at the steel/steel friction interface to further lower the interfacial friction.The results provide a new opportunity to further optimize the tribological performance of diketone superlubricity system,especially towards the lubrication of mechanical engineering materials.

关键词： superlubricity oxygen content steel/steel interface diketone chelate

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