Journal of Cleaner Production
·
2022
·
IF 11.072
Liyu Chen,Jiaxin Yang,Yifan Zhang,Shaohua Wu,Youjian Yang,Wenju Tao,Zhaowen Wang
The synthesis of an Al–Zr master alloy in KF–AlF 3 –ZrO 2 molten salt by combining aluminothermic reduction and molten salt electrolysis processes was studied. The effects of reduction parameters such as stirring, reaction time, Al/ZrO 2 mass ratio and temperature on the Zr content and Zr recovery rate were studied and optimized. Under the optimal conditions of stirring, reaction time of 4 h, Al/ZrO 2 mass ratio of 3 and temperature of 960 °C, an Al–Zr master alloy can be obtained with a Zr content of 6.78 wt% and Zr recovery rate of 29.85%. The characterization results of the alloy show that the main phases contain Al and Al 3 Zr. And the Al 3 Zr appears as long rod-shaped or tetragonal shapes, which influenced by the Zr content and cooling rate. In addition, the reduced molten salt is electrolyzed to further extract Zr from the molten salt. The results show that the Zr remaining in the molten salt is completely recovered with a Zr recovery rate up to 94.72%. This two-step process is feasible for the large-scale extraction of Zr in molten salts to produce Al–Zr master alloys.
研究领域:
冶金工程
·
材料科学
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DOI
高影响因子
Scientific Reports
·
2019
·Vol. 9
·期 1
·1-9
·
IF 4.011
Zhao Shijiao,Ma Jingtao,Xu Rui,Lin Xuping,Cheng Xing,Hao Shaochang,Zhao Xingyu,Deng Changsheng,Liu Bing
Zirconium compounds has been widely attention over the last decades due to its excellent physical and chemical properties. Zirconium nitride nanopowders were synthesized via a simple direct carbothermic nitridation process of internal gel derived zirconia in the presence of nano-sized carbon black. The effects of reaction temperature, dwell time and molar ratio of carbon black to Zr (C/Zr) on the phase composition, grain size and crystal parameters of products were studied. Based upon the analysis of crystallite phase evolution and microstructure characterization, it was found that zirconium oxynitride is intermediate product and then O atoms in oxynitride were extracted by oxygen getter, carbon black. Anion sites were directly replaced by N atoms to form rock-salt type nitride in carbothermic nitridation process.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Ze Zhu,Xiaoqian Zhang,Ying Peng,Zhenfeng Guo,Yongshuai Xie,Benxue Liu,Guanghui Zhang,Luyi Zhu,Xinqiang Wang,Yonggang Jiang,Jian Feng
Rare earth zirconates have incomparable chemical thermophysical properties , yet the difficulty of preparation methods limit their application as fibrous material. In present work, a spinnable La 2 Zr 2 O 7 precursor, named as carboxylate lanthanum-zirconium (COLZ), was developed using carboxylic acids as structural and functional ligands. When COLZ is in its liquid state, it can be readily processed into desired shapes, allowing preparation of high aspect ratio precursor fibers with dense and bonding-strong internal structures. The spinnability was explained by the transformation from solid to liquid state under external forces, in which dynamic bridging of carboxylate and hydroxyl between nano-sized colloidal particles play a key role. Due to weakly acidic ligands, organics in COLZ can be easily removed, making direct heat treatment at the target temperature possible, which is beneficial for massive production. The strategy of developing spinnable precursor could also be applied to prepare other rare earth zirconate fibers or new multi-oxide fibers.
研究领域:
材料科学
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化学工程
·
纳米技术
·
热管理
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2024
·Vol. 29
·期 12
·2798
·
IF 4.2
Shenglong Shi,Jinsheng Sun,Shanbo Mu,Kaihe Lv,Jingping Liu,Yingrui Bai,Jintang Wang,Xianbin Huang,Jiafeng Jin,Jian Li
To investigate the effect of the chemical composition of a metal–organic crosslinker on the performances of fracturing fluid in high-temperature conditions, four zirconium (Zr) crosslinkers and one aluminum–zirconium (Al-Zr) crosslinker with a polyacrylamide were used. The crosslinkers possessed the same Zr concentration, but they differed in component amounts and the order of the addition of the crosslinker components, leading to different chemical compositions in the crosslinkers. The fracturing fluids prepared by different tested crosslinkers were compared in terms of properties of rheological behavior, sand-carrying ability, microstructure, and gel breaking characteristics. The results showed that the fracturing fluids prepared by zirconium lactic acid, ethanediamine, and sorbitol crosslinkers offered the slowest viscosity development and highest final viscosity compared to the zirconium lactic acid crosslinker and the zirconium lactic acid and ethanediamine crosslinker. The zirconium sorbitol, lactic acid, and ethanediamine crosslinker exhibited a faster crosslinking rate and a higher final viscosity than the zirconium lactic acid, ethanediamine, and sorbitol crosslinker; the crosslinker showed crosslinking density and crosslinking reactivity, resulting in more crosslinking sites and a higher strength in the fracturing fluid. The Al-Zr-based crosslinker possessed better properties in temperature and shear resistance, viscoelasticity, shear recovery, and sand-carrying ability than the Zr-based crosslinker due to the synergistic crosslinking effect of aluminum and zirconium ions. The tertiary release gelation mechanism of the Al-Zr-based fracturing fluid achieved a temperature resistance performance in the form of continuous crosslinking, avoiding the excessive crosslinking dehydration and reducing viscosity loss caused by early shear damage. These results indicated that the chemical compositions of metal–organic crosslinkers were important factors in determining the properties of fracturing fluids. Therefore, the appropriate type of crosslinker could save costs without adding the additional components required for high-temperature reservoirs.
研究领域:
石油工程
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材料化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·
IF 3.5
Chengwan Yang,Xinyang Li,Jie Yu,Jieyan Yuan,Ming Li,Xiaoye Hu,Zhulin Huang,Yue Li
Zirconium boride (ZrB 2 ) whiskers hold significant potential for toughening ultra-high temperature ceramics (UHTCs). Yet, their fabrication remains challenging due to limited knowledge of the microstructure evolution. Herein, high-purity ZrB 2 whiskers were successfully prepared by electrospinning combined with carbothermal reduction. Specifically, a precursor solution containing Zr–O–C–B networks stabilized through hydrogen bonds with polyvinyl pyrrolidone was synthesized as a spinnable ZrB 2 precursor. High-purity ZrB 2 whiskers with a diameter of ca . 200 nm and a length of 5–10 µm were obtained by precise heat treatment of ZrB 2 precursor fibers. In this process, ZrO 2 grains formed initially and transformed into ZrB 2 grains through carbothermal reduction, which further converted into ZrB 2 whiskers through a solid-liquid-solid mechanism. To testify to the toughening effect for UHTCs, the ZrB 2 whiskers were added into ZrB 2 powders and followed by sintering. This strategic addition of 5 wt% ZrB 2 whiskers led to a 19% enhancement in the fracture toughness of ZrB 2 bulk. This study illuminated the preparation strategy and formation mechanism for ZrB 2 whiskers and their application for toughening UHTCs.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NUCLEAR MATERIALS
·
2020
·
IF 2.485
Yi Ding,Zhengdi Jiang,Tianheng Xiong,Zimei Bai,Dandan Zhao,Hui Dan,Tao Duan
Zircon is important ceramic used widely due to its excellent properties, in particular for nuclear waste immobilization . However, it is difficult to obtain mono-phase zircon with high yield, usually result in double-phase ZrO 2 /ZrSiO 4 ceramics. Herein, Ce-doped double-phase 0.2Zr 1- x Ce x O 2 /Zr 1- y Ce y SiO 4 (0 ≤ x + y ≤ 1) ceramics were fabricated and their phase and microstructure evolution were studied. The results demonstrated that Ce content has great influence on the phase composition and microstructure. The ceramics with 0 ≤ x + y < 0.1 are tetragonal-ZrSiO 4 , monoclinic-ZrO 2 and tetragonal-ZrO 2 phases, with 0.1 ≤ x + y ≤ 0.3 are tetragonal-ZrSiO 4 , monoclinic-ZrO 2 , tetragonal-ZrO 2 and cubic-ZrO 2 phases, with 0.3 < x + y ≤ 0.6 are tetragonal-ZrSiO 4 , tetragonal-ZrO 2 and cubic-ZrO 2 phases, and with 0.6 < x + y ≤ 1 are cubic-ZrO 2 and Ce 2 Si 2 O 7 phases. With increasing Ce-doping content, the ZrSiO 4 retained the tetragonal phase, while ZrO 2 transformed from monoclinic to stable cubic phase. Furthermore, lattice parameters , grain size and compactness increased with increasing Ce content.
研究领域:
材料科学
·
核废物处理
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2014
·
IF 6.007
Jun Yu,Zhichun Si,Lei Chen,Xiaodong Wu,Duan Weng
A zirconium phosphate @ Ce 0.75 Zr 0.25 O 2 (ZP/CZ) catalyst was synthesized by impregnating zirconium phosphates on Ce 0.75 Zr 0.25 O 2 microspheres. Catalysts with different structures were also synthesized by various methods to illustrate the structure advantage of ZP/CZ catalyst in selective catalytic reduction of NO x by ammonia (NH 3 -SCR). The catalysts were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), BET surface area, Infrared (IR) spectra, Ultraviolet-visible (UV–vis) spectroscopy, X-ray photoelectron spectroscopy (XPS), H 2 -temperature programmed reduction (TPR) and diffuse reflectance infrared Fourier transformed spectra (DRIFTS) of NH 3 /NO x adsorption. ZP/CZ catalyst presents excellent catalytic activity at 250–450 °C with a good N 2 selectivity under high space velocity of 300,000 h −1 . Firstly, the zirconium phosphate provides adsorption sites for ammonia on the surface of the catalyst and the cerium sites in the core act as the redox sites for NO oxidation. The pre-combination of zirconium and phosphate can reduce the strong interactions between phosphates and cerium ions. Therefore, the mobility of surface lattice oxygen on Ce 0.75 Zr 0.25 O 2 catalyst is retained, which is essential to obtain a catalyst with high NH 3 -SCR activity at low temperatures. Moreover, NH 4 NO 3 has proved to be an important intermediate for the NH 3 -SCR reaction on the surface of ceria based catalysts. The ZP/CZ catalyst preserves plenty of oxygen vacancies, facilitating the Ce 4+ → Ce 3+ redox circles and therefore promotes the nitrites/nitrates formation and desorption on catalyst. Two distinct adsorption sites for NH 3 and NO x result in a close contact between ads-NH 3 /NH 4 + and ads-NO 3 − /NO 2 − species on ZP/CZ catalyst, which can react with NO rapidly with the participation of active surface lattice oxygen.
研究领域:
环境科学
·
催化化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·
IF 3.5
Kangkang Yuan,Chen Shu,Kexin Meng,Wenjun Zhao,Guosheng Sun,Jien Zhu,Jin Chen,Yunlong Huang,Chengshun Li,Xiaotong Jin
Calcium zirconate (CaZrO 3 )-based fibrous membrane is a promising candidate in high-temperature areas for its high melting point, good phase stability up to 1900°C, low thermal conductivity, and low cost. To further enhance the high temperature flexibility of CaZrO 3 -based fibrous membrane without sacrificing stability, modification methods should be conducted. In the present work, a CaZrO 3 -BaZrO 3 dual-phasic structure was proposed to modify the high-temperature properties from the standpoint of phase competition. CaZrO 3 -BaZrO 3 fibrous membranes were prepared with the combination of the electrospinning method and pyrolysis process. The decomposition process, phase transformation, crystallize size, and microstructure evolution of CaZrO 3 -BaZrO 3 precursor fibrous membrane were characterized. The grain size, particle size, NIR reflectivity, high-temperature stability, fire retardancy, and high-temperature flexibility were also characterized and compared with other CaZrO 3 -based fibrous membranes. The higher thermal stability and flexibility of the CaZrO 3 -BaZrO 3 fibrous membrane at 1200°C would make it a good candidate for high-temperature insulating, high-temperature supporting, and high-temperature filtration.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Shaolong Li,Yusi Che,Jianxun Song,Yongchun Shu,Jilin He,Baoqiang Xu,Bin Yang
A single phase zirconium oxycarbonitride was prepared through a carbothermal reduction route at 1600 °C in nitrogen atmosphere using ZrO 2 and graphite powder as raw materials. The hot-pressed zirconium oxycarbonitride block has good stability in the NaCl-KCl melt. The anodic dissolution behavior of zirconium oxycarbonitride and the reduction mechanism of zirconium ion in NaCl-KCl melt were studied by linear sweep voltammetry, electrochemical impedance spectroscopy, cyclic voltammetry and square wave voltammetry. The results show that zirconium in the anode is oxidized to Zr 2+ ions and dissolved in the molten salt. The zirconium ions diffuse to the cathode and are reduced to zirconium metal by transferring two electrons in one step. Potentiostatic electrolysis at −2.9 V was performed between a Mo rod cathode and ZrC x O y N z anode. The cathode product was detected to be zirconium metal, which indicated that zirconium oxycarbonitride was a suitable consumable anode for the electrolytic preparation of zirconium metal.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
Xi-Fei Ma,Xiao Huang,Zhuang Kang,Guo-Jun Zhang,Hongjie Luo
Due to the extremely harsh reaction conditions, it is very difficult to control the particle morphology during the synthesis of ZrC , a well-known ultra high temperature ceramic material. In this paper, carbon encapsulated zirconia microspheres (ZrO 2 @C) are synthesized via two consecutive hydrothermal reactions in one pot. After carbothermal reduction, ZrC particles with controlled spherical morphology can be prepared. The spherical morphology suggests that carbon diffuses into zirconia during carbothermal reduction. The influences of reactant concentrations, reaction time and temperature on the microencapsulation process are also investigated. Meanwhile, as a comparison, zirconia coated carbon microspheres (C@ZrO 2 ) are also prepared, which results in ZrC particles with layered structure.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2017
·
IF 2.572
Wang Ning,Chen Xueyan,Lu Kezhen,Zhang Xingxiang,Xiaofei Ma
Zirconium-based carbon nanofibrous mats (ZrCFs) with three-dimensional macrostructures were prepared by the carbonization of the Polyacrynitrile (PAN) nonwoven mats containing zirconium oxychloride from air jet spinning. ZrCFs exhibited the elastic, flexible and fluffy characteristics, much different from the carbon nanofibres without zirconium. Nano zirconium compounds were uniformly distributed in carbon nanofibres, ascribed to the chelation interaction between Zr + and PAN precursor. XRD showed that the ZrO 2 , ZrC and ZrN structures formed in carbon nanofibres of ZrCFs, which could prevent carbon nanofibres from fusing and shrinking. When nitrogen was introduced, ZrCFs could further reduce the charge transfer resistance. The flexible ZrCFs have the potential electric application, which can also be extended to the functional textiles and catalysis.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2021
·Vol. 52
·期 5
·3276-3287
·
IF 2.47
Li Shaolong,Che Yusi,Song Jianxun,Shu Yongchun,Xu Baoqiang,He Jilin,Yang Bin
A single-phase zirconium oxycarbide was successfully synthesized by carbothermal reduction route at 1600 °C for 8 hours under argon atmosphere using ZrO 2 and graphite powder as raw materials (the molar ratio of ZrO 2 to graphite is 1:2.6). Effects of temperature, reaction time and molar ratio of ZrO 2 to graphite on zirconium oxycarbide preparation were also investigated. The microstructure and composition of the products were characterized by X-ray diffraction, scanning electron microscopy, energy spectroscopy X-ray and ONH analyzer. The hot-pressed single-phase zirconium oxycarbide has good stability in molten NaCl–KCl. Subsequently, anodic dissolution of zirconium oxycarbide and the reduction mechanism of the dissolved zirconium ion in molten NaCl–KCl were investigated by a series of electrochemical technologies. The results show that the zirconium ion species dissolved in molten NaCl–KCl is Zr(II). Zr(II) is transferred from the anode to the cathode in the molten salt and is reduced to zirconium metal. Potentiostatic electrolysis at − 2.9 V was carried out using ZrC x O y as anode. CO gas was detected in the exhaust gas during the electrolysis, which can be explained as the combination of C and O atoms in ZrC x O y . The cathode deposit was detected to be zirconium metal. The results show that zirconium oxycarbide was a suitable anode material for the electrolytic synthesis of zirconium metal.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）