JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Liyu Chen,Jiaxin Yang,Youjian Yang,Jiangyu Yu,Xianwei Hu,Wenju Tao,Zhaowen Wang
The fluorine salt system is a potential electrolyte for the preparation of metals and alloys from metal oxides via molten salt electrolysis. The solubility of ZrO 2 in KF–AlF 3 –Al 2 O 3 molten salts (KF/AlF 3 molar ratio = 2.1–2.8, Al 2 O 3 content = 0–9 wt%) was measured using the isothermal saturation method in this study. The influence of temperature and electrolyte composition on ZrO 2 solubility was analyzed. The dissolution mechanism of ZrO 2 was then determined based on the analysis of X–ray diffraction and Raman spectroscopy results. The experimental results show that the solubility of ZrO 2 in the 2.4KF–AlF 3 molten salt at 1233 K could reach up to 6.62 wt%. Besides, the solubility of ZrO 2 increase with the increase of temperature, the decrease of KF/AlF 3 molar ratio and Al 2 O 3 content. X-ray diffraction and Raman spectroscopy analyses show that the dissolved ZrO 2 in KF–AlF 3 molten salts existed in the form of [Zr 2 O 2 F 6 ] 2− and [ZrF 6 ] 2− complex ions under melting and cooling conditions, respectively. And the dissolution process of ZrO 2 in KF–AlF 3 molten salts can be described using a mass transfer control model.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOM
·
2019
·Vol. 72
·期 1
·247-252
·
IF 2.305
Yan Hengwei,Liu Zhanwei,Ma Wenhui,Huang Liqiang,Wang Chengzhi,Liu Yingxin
The development of low-temperature aluminum electrolysis makes it possible to reduce energy consumption and greenhouse gas emissions. The KF-NaF-AlF 3 -based electrolyte is a promising low-temperature electrolyte for aluminum reduction. The liquidus temperatures of KF-NaF-AlF 3 electrolytes with a total cryolite ratio (CR t ) fixed at 1.3–2.0, and with different concentrations of NaF (with a step change of 5 mol.%), were investigated by the cooling curve method. The results showed that the liquidus temperature of KF-NaF-AlF 3 mixtures increases with the increase of the CR t , which has a bigger influence on the liquidus temperature than the traditional NaF-AlF 3 electrolyte currently used in aluminum smelters. When the content of NaF is 10–20 mol.%, the curves of the liquidus temperature vs. NaF content reach a peak. When the NaF content ranges from 30 to 40 mol.%, the liquidus temperature is relatively low (695–900°C). The precipitated order of the compounds in molten KF-NaF-AlF 3 electrolytes with a CR t of 1.3 is as follows: K 2 NaAlF 6 (or K 3 AlF 6 ) → Na 3 Al 5 F 14 → K 2 NaAl 3 F 12 → KAlF 4 .
研究领域:
材料科学
·
冶金学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 16
·12782-12787
·
IF 3.289
Ye-Min Lu,Hu Li,Jian He,Yan-Xiu Liu,Zhi-Bing Wu,De-Yu Hu,Song Yang
Partially hydroxylated AlF3 (denoted as AlF3) was synthesized by using a sol–gel method, and unambiguously characterized by FT-IR, XRD, NH3-TPD, SEM, TEM, N2 adsorption–desorption, and FTIR (pyridine-adsorption) techniques. The resulting mesoporous material (AlF3) simultaneously bearing Lewis and Brønsted acid sites was efficient for producing 5-hydroxymethylfurfural (HMF) from glucose, and an optimized HMF yield of 57.3% at a glucose conversion of 95.5% was obtained within 10 h at 140 °C. The effects of reaction temperature, time, catalyst amount, solvent and substrate type, and the amount of Brønsted/Lewis acid sites on conversion of glucose to HMF were also investigated. The existence of both Lewis and Brønsted acid sites in AlF3 was found to play a key role in glucose-to-HMF conversion.
研究领域:
化学工程
·
催化化学
✓ 已验证
DOI
高影响因子
Nature Communications
·
2022
·Vol. 13
·期 1
·1-9
·
IF 17.694
Cao Peisheng,Zheng Haoyue,Wu Peng
Designing organic fluorescent and phosphorescent materials based on various core fluorophore has gained great attention, but it is unclear whether similar luminescent units exist for inorganic materials. Inspired by the BX 6 octahedral structure of luminescent metal halide perovskites (MHP), here we propose that the BX 6 octahedron may be a core structure for luminescent inorganic materials. In this regard, excitation-dependent color-tunable phosphorescence is discovered from α-AlF 3 featuring AlF 6 octahedron. Through further exploration of the BX 6 unit by altering the dimension and changing the center metal (B) and ligand (X), luminescence from KAlF 4 , (NH 4 ) 3 AlF 6 , AlCl 3 , Al(OH) 3 , Ga 2 O 3 , InCl 3 , and CdCl 2 are also discovered. The phosphorescence of α-AlF 3 can be ascribed to clusterization-triggered emission, i.e., weak through space interaction of the n electrons of F atoms bring close proximity in the AlF 6 octahedra (inter/intra). These discoveries will deepen the understanding and contribute to further development of BX 6 octahedron-based luminescent materials.
研究领域:
材料科学
·
光学材料
·
无机化学
✓ 已验证
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2018
·Vol. 49
·期 4
·2071-2076
·
IF 1.834
Yan Hengwei,Yang Jianhong,Liu Zhanwei,Wang Chengzhi,Ma Wenhui
The cryolite ratio (CR) is an important parameter for the electrolyte in aluminum reduction cells. The measurement method for the CR of the KF-NaF-AlF 3 system acid (CR < 3) electrolyte by means of electrical conductivity was initially developed, and the formula for calculating the CR was deduced. This method has the advantages of simple operation and high precision. In addition, the relative standard deviations (RSD) of the measurement are < 1.2 pct, and the analysis error of the NaF or KF content has little effect on the determination of the CR.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Yiwei Sun,Xiaoli Wei,Wei Zhang,Zhen Wang,Jianhai Jiang,Fangcao Liu,Bing Liu,Wenfeng Han
Conversion of potent greenhouse gases, hydrofluorocarbons (HFCs), to value-added hydrofluoroolefins (HFOs) is of great importance. AlF3 catalysts play a major role in this process. Formation and maintenance under coordinated Al are the key to prepare efficient catalysts. Herein, carbon interacted AlF3 nanoclusters catalyst (AlF3–SAPO-5) was effectively achieved with SAPO-5 molecular sieves as precursors via pyrolysis followed by in situ fluorination. This process results in a strong interaction between the carbonaceous material and active aluminum (Al) species. The results show that AlF3–SAPO-5 possesses both high activity and thermal stability. For 1,1-difluoroethane (HFC-152a) dehydrofluorination, the conversion can reach up to 95% at a reaction temperature of 350 °C. The reaction rate is almost 4 times higher than that of AlF3 prepared by traditional pyrolysis (AlF3-py). It implies that the confinement effect contributes to the formation of AlF3 nanoclusters with abundant 4- and 5-coordinated Al species stabilized by the F–Al–O–C structure. In addition, the carbon-interacted AlF3 nanoclusters exhibit superb sintering resistance. Given its fantastic activity and thermal stability, the carbon-interacted AlF3 nanoclusters show great potential for the catalytic dehydrofluorination of fluorinated alkanes.
研究领域:
化学工程
·
材料科学
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Yifan Zhang,Xianwei Hu,Jiaxin Yang,Liyu Chen,Wenju Tao,Fengguo Liu,Zhongning Shi,Zhaowen Wang
Aluminum-vanadium intermediate alloy is a significant raw material for the fabrication of high-performance titanium alloys . In the present study, the electrochemical behavior of NaVO 3 on a solid molybdenum and liquid aluminum electrode is systematically investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) in the NaF-KF-AlF 3 molten salt and the formation mechanism of Al-V intermetallic compounds is emphatically analyzed. The results show that the electrochemical reduction of VO 3 − on the solid molybdenum electrode is a multi-step process and low-valence vanadium oxide (V 2 O 3 ) is obtained. In contrast, the electrochemical reduction of VO 3 − to V 2 O 3 on liquid aluminum electrode is through one-step process and the deposition potential is more positive than that on molybdenum electrode owing to the depolarization effect of the liquid aluminum electrode. In addition, Al-V intermetallic compounds are obtained on the liquid aluminum electrode by potentiostatic electrolysis. The reduction process of VO 3 − on the liquid aluminum electrode is described as: the electrochemical process is started by the direct electro-reduction of VO 3 − to V 2 O 3 , which is further converted to Al-V intermetallic compounds under the combined effect of electrochemical and aluminothermic reduction, with the latter playing a dominant role.
研究领域:
冶金学
·
材料科学
✓ 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
·3490-3496
·
IF 2.47
Yan Hengwei,Huang Liqiang,Ma Wenhui,Liu Zhanwei,Qin Bo
The NaF-KF-AlF 3 -based electrolyte is a promising low-temperature electrolyte for aluminum reduction. The solubility and dissolution rate of alumina in NaF-KF-AlF 3 -LiF-CaF 2 melt with a cryolite ratio (CR) ranging from 1.5 to 1.8 were investigated by the rotating corundum disk method at 1073 K to 1153 K. The effect of the composition and temperature of the melt on the solubility and dissolution rate of alumina were discussed. The results show that the solubility and dissolution rate of alumina in the melt decrease with the increase of LiF and CaF 2 content, and the effect of LiF on the alumina solubility is greater than that of CaF 2 . The decrease of the CR and temperature lead to a marked reduction of the alumina solubility and alumina dissolution rate. The dissolution rate of alumina depends on the dissolution rate in the first 5 minutes. The alumina dissolution is a zero-order reaction in the first 5 minutes, and a first-order reaction in the next 30 minutes.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
Silicon
·
2025
·
IF 3.3
Yang Yonghui,Fan Chao,Yang Pengchen,Liu Zhanwei,Yan Hengwei
This study investigated the effect of aluminum oxide (Al 2 O 3 ) additives on the properties of NaF-AlF 3 -SiO 2 melts. The liquid-phase line temperature was determined through thermal analysis, while the solubility and volatilization loss of silicon dioxide (SiO 2 ) were evaluated using the rotating quartz disk method and volatilization experiments. The dissolution mechanism of Al 2 O 3 in the melt was explored through thermodynamic analysis and experimental validation. The results indicated that Al 2 O 3 addition significantly decreased liquid-phase line temperature, enhanced SiO 2 solubility, and reduced volatilization losses. These findings provide a theoretical basis for optimizing the electrolysis process of Al–Si alloys, which contribute to improved melt performance, enhanced energy efficiency, and reduced volatilization losses, thereby promoting increased efficiency in industrial applications.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Haiping Zhou,Gang Wang,Liping Wang,Zhenhua Zhang,Huiliang Hou,Qifan Zhong,Jin Xiao
Industrial alumina was used as raw material in the high-temperature calcination process, and AlF 3 was introduced to promote mass transfer in the gas phase. The calcination environment, such as sealing, calcination temperature, and holding time, was analyzed to enhance the effect of AlF 3 to promote the crystal growth of alumina. Here, round-like flake α-Al 2 O 3 with an average particle size (D50) of about 18–38 μm were obtained at low dosages (0.1–0.4 wt%) of AlF 3 . The morphology and particle size of α-Al 2 O 3 were further adjusted by introducing different types of micron-scaled nuclei as template inducers. Round-like flake and spherical-like large single crystals α-Al 2 O 3 with an average particle size greater than 35 μm were obtained, respectively, with 65 wt% of 15 μm flake and 10 μm bulk α-Al 2 O 3 nuclei added. In addition, the regulation mechanism of AlF 3 and nuclei on alumina crystal growth was also discussed. Finally, a theoretical basis and technical support for preparing high-performance, low-cost, and high thermal conductivity alumina fillers was provided.
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
CERAMICS INTERNATIONAL
·
2015
·
IF 2.605
Shengli Pang,Yonggang Wang,Tao Chen,Xiangqian Shen,Xiaoming Xi,Daqian Liao
Lithium (Li)-rich layered oxides are considered promising cathode materials for Li-ion batteries because of their favorable properties. Here, we report our recent finding in the novel oxide, aluminum fluoride (AlF 3 )-modified Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNCAF), which was synthesized via a facile, cost-effective and readily scalable solid-state reaction. LMNCAF possess an F and Al co-doped core structure with a LiF nano-coating on its surface which leads to considerably enhancement in the electrochemical performance of the oxide. The initial discharge capacity (at 0.05 C) increased from 212 mA h g −1 for Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 to 291 mA h g −1 for LMNCAF. A much higher discharge capacity of 211 mA h g −1 was obtained for LMNCAF after 99 charge/discharge cycles at 0.2 C compared with that of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (160 mA h g −1 ). Our preliminary results suggest that AlF 3 modification is an effective strategy to tailor the physicochemical and electrochemical properties of Li-rich layered oxides.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2019
·Vol. 72
·期 1
·239-246
·
IF 2.305
Peng Jianping,Wei Zheng,Di Yuezhong,Wang Yaowu,Sun Ting
NaF-KF-LiF-AlF 3 -based low-temperature electrolytes have attracted great interest because of their potential to optimize and improve current industrial aluminum production methods. In the present study, the saturated alumina solubility in quaternary NaF-KF-LiF-AlF 3 -based melts (total cryolite molar ratio \( {\text{CR}} = \left( {n_{\text{NaF}} + n_{\text{KF}} + n_{\text{LiF}} } \right)/n_{{{\text{AlF}}_{3} }} \) of 1.3) with both KF and LiF content of 0 mol.% to 20 mol.% were evaluated by measuring the weight loss of a rotating corundum disk over the temperature range of 800–920°C. The effects of the KF content, LiF content, and temperature on alumina solubility are discussed in detail. The results fit well with the following empirical equation within the temperature of 830–890°C: ω (Al 2 O 3 ) sat = A × ( t /1000) B , where A = 0.3101[KF] − 0.1254[LiF] − 0.0057[KF] 2 + 0.0028[LiF] 2 + 4.486, B = 0.3839[KF] + 0.0368[LiF] − 0.0140[KF] 2 + 0.0057[LiF] 2 + 4.913, and t is the temperature in Celsius. Alumina solubility diagrams at various temperatures are illustrated based on the empirical regression equation obtained. Finally, some problems and challenges preventing the application of these low-temperature melts in industry are discussed.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
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