CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Zhixin Wang,Yaowu Wei,Huayun Sun,Junfeng Chen,Bingqiang Han
ZrC was synthesized using sol-gel-like methods and carbothermic reduction techniques, employing Zr(OPr n ) 4 and carbon black as raw materials and CaF 2 as catalyst. High-crystallinity ZrC were obtained after a 20-minute hold at 1550°C. The effects of CaF 2 content and heat treatment temperature on structural transformation of the precursor, phase evolution, microstructural evolution and elemental composition analysis, as well as to analyze the catalytic mechanism of CaF 2 were investigated. The results indicated that this method enables effective and uniform mixing of ZrO 2 and carbon black. Adding CaF 2 promoted the deoxygenation of ZrO 2 and ZrC x O 1-x to ZrC, reducing the initial formation temperature of ZrC to 1300°C. The carbothermal reaction was nearly complete at 1500°C, yielding a composition of ZrC 0.951 O 0.049 at 1600°C. Thermodynamic calculations showed that CaF 2 react with ZrO 2 to form an intermediate phase of ZrF 4 , altering the reaction mechanism and reducing the theoretical initial synthesis temperature of ZrC to 1000°C.
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
Mineral Processing and Extractive Metallurgy Review
·
2017
·
IF 1.219
Zijian Su,Yuanbo Zhang,Bingbing Liu,Yingming Chen,Guanghui Li,Tao Jiang
A selective reduction volatilization (SRV) process developed by the authors was effective to remove tin from the complex tin-bearing iron concentrates. It is reported that many gangue minerals of quartz, calcite, and fluorite are existent in the concentrates. Our previous studies investigated the effect of quartz and calcite on the removal of tin. In this study, the effect of fluorite (calcium fluoride) was conducted, and pure CaF2 was added into the tin-bearing iron concentrates to investigate how CaF2 affected the tin volatilization behavior under different roasting conditions. The effect of CaF2 on the phase transformation of SnO2 was also determined using SEM-EDS and XRD. The results indicated that SnF2 was much easier to volatilize than SnO under CO-CO2 atmosphere in the presence of CaF2, so the calcium fluoride in the concentrates was beneficial to promote the tin removal during the SRV process.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2021
·
IF 7.267
Ping Hu,Yang Feng,Qi Li,Chuan-Huang Lin,Yu-Hao Ning,Yi-Ting Li,Lin-Ping Yu,Zhong Cao,Ju-Lan Zeng
Microencapsulation of phase change materials (PCMs) with functional shell materials such as luminescent material could endow the obtained microencapsulated PCMs (MPCMs) with improved latent heat storage properties. The PCM core in turn could protect the luminescence shell from large temperature shifting and thus improve its performance. In this work, a series of MPCMs derived from n -octadecane (ODE) core and CaF 2 shell were synthesized via a self-assembly method. The effects of the preparation conditions, including the core/shell mass ratio, the dosage of the emulsifier (styrene-maleic anhydride copolymer , SMA) and the dosage of the chelator (Na 3 Cit), on the properties of the prepared ODE@CaF 2 MPCMs were investigated and the optimal preparation condition was obtained. The MPCM obtained according to the optimal procedure (MPCM1) exhibited an encapsulation ratio of 54.02% and a latent heat of 131 J/g with negligible leakage. It also possessed excellent thermal reliability and significantly improved thermal conductivity . The MPCM1 could not only be utilized as good latent heat storage material and thermal regulation material, but also provided one new idea to prevent the thermal quenching of luminescence materials. In addition, this work could shed some light on the high-value utilization of recovered fluorine resources.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jianfeng Wu,Xinxin Shi,Shaoheng Liu,Xiaohong Xu,Yaqiang Shen,Deng Zhang
The absorptivity of endothermic materials serves as a critical index for solar thermal power photothermal conversion systems, and ceramic-based endothermic materials characterized by high absorptivity also exhibit elevated sintering temperatures. In this study, CaF 2 was employed as an additive to investigate its effects on the physical properties and microstructure of the samples, with a particular focus on the mechanism by which CaF 2 reduces the sintering temperature of corundum-based endothermic ceramics. The results showed that the G2 sample (1 wt% CaF 2 ), sintered at 1650 °C, displayed the best physical properties, including 93 % absorptivity, 165.43 MPa bending strength. The sintering temperature of the CaF 2 -doped G-series samples was around 60 °C lower due to liquid-phase calcium hexaaluminate formation from CaF 2 and Al 2 O 3 , which enhanced atomic migration and facilitated ceramic matrix sintering. Additionally, the capillary forces of the liquid-phase calcium hexaaluminate promoted ceramic matrix shrinkage and accelerated corundum-based grain growth through the dissolution-precipitation mechanism, leading to densification. Moreover, the G2 sample exhibited excellent durability, with absorptivity decreasing by only 1.9 % after 100 h at 1000 °C.
研究领域:
材料科学
·
太阳能技术
✓ 已验证
产品关联
DOI
高影响因子
Environmental Science-Nano
·
2025
·
IF 5.1
Guangxin Liao,Li Li,Zeyu Kang,Xibing Zhou,Jie Li,Zhulin Xue,Huiqin Gao,Zhang Lin,Weizhen Liu
Fluorine-containing sludge (FCS), an industrial hazardous waste generated during processes such as fluorine chemical production and solar cell manufacturing, is highly toxic and challenging to degrade, posing significant environmental threats. In this study, we developed a promising new method to convert FCS into monodisperse, highly crystalline, and high-purity CaF2 nanomaterials using low-concentration inorganic or organic acids as regulators under hydrothermal conditions. This method involved regulating the dissolution–deposition behaviours of the CaF2 matrix, controlling impurity transformation, promoting the growth of CaF2 crystals and achieving deep removal of impurities. Under optimized conditions (0.5 M hydrofluoric acid, liquid-to-solid ratio of 10 : 1, 180 °C, and 24 h), the produced CaF2 exhibited 98% purity, 99% crystallinity and excellent monodispersity. The purification and impurity separation mechanism of CaF2 in FCS was studied by analysing the dissolution–deposition process, the crystal growth behavior of CaF2, and the migration and transformation of impurities under the treatment. It was revealed that hydrofluoric acid, as a regulator, plays the following important roles: (i) targeted conversion of calcium in sludge into CaF2 and enhancement of its purity, (ii) regulation of the digestive ripening process of fine CaF2 particles and enhancement of the dispersity and crystallinity of the CaF2 product, and (iii) release of encapsulated and lattice-doped impurities and dissolution of other solid impurities into the liquid phase. Ultimately, this process yielded monodisperse, high-crystallinity, acid-grade CaF2 nanomaterials. This study provided critical insights into the nano-structure control and transformation of hazardous FCS, thereby developing a sustainable approach to fluorine resource recovery.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE-POLAND
·
2016
·Vol. 32
·期 3
·358-363
·
IF 0.533
Zhou W. B.,Cai F. F.,Zhi G. L.,Mei B. C.
Highly-transparent trivalent erbium ion doped calcium fluoride (5 mol % Er:CaF 2 ) ceramics were fabricated by a hotpressing (HP) method using high-purity Er:CaF 2 nanoparticles, which were synthesized by co-precipitation method. The mean grain size of the nanoparticles was about 24.7 nm. The nanoparticles were sintered at 600 °C, 700 °C, 800 °C and 900 °C, respectively, for 30 min under a uniaxial pressure of 30 MPa and vacuum of 10 −3 Pa with 1 mol % lithium fluoride (LiF) as sintering additive. The 5 mol % Er:CaF 2 ceramics sintered at 800 °C exhibits high density and pore-free microstructure with an average grain size of about 8 μm. The optical transmittance of the transparent ceramics is close to 85 % at visible and nearinfrared wavelengths. The strong and broad absorptions peaks corresponding to characteristic absorption of trivalent erbium ions make the ceramics a potential candidate for infrared and upconversion laser operating.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2017
·Vol. 52
·期 10
·5857-5870
·
IF 2.599
Zhao Bei,Shen Dingyi,Tan Qinyue,Tang Jianfeng,Zhou Xianju,Hu Shanshan,Yang Jun
CaF 2 :Ln 3+ (Ln = Ce, Tb, Eu) phosphors with highly uniform shapes have been successfully synthesized by a simple hydrothermal method directly. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) and lifetime. The results indicated that the pH values, organic additive and reaction time have a significant effect on the morphology and dimensions of CaF 2 microcrystals and the possible formation mechanism was also proposed. Furthermore, the energy transfer from Ce 3+ to Tb 3+ and from Tb 3+ to Eu 3+ and from Ce 3+ to Tb 3+ to Eu 3+ was observed and the corresponding mechanisms were discussed in detail. The CaF 2 :Ln 3+ phosphors may have potential optical applications in near-UV and violet LEDs.
研究领域:
材料科学
·
无机化学
·
光学材料
·
纳米技术
·
固体化学
✓ 已验证
DOI
高影响因子
Micro & Nano Letters
·
2018
·Vol. 13
·期 3
·393-396
·
IF 0.841
Ting Fan,Jiantao Lü,Yongfa Huang,Guoji Li
Monodisperse oleic acid (OA) modified Eu 3+ and Li + codoped CaF 2 nanoparticles are presented in this work. The as-obtained nanoparticles, with a hexagonal shape, can be well-dispersed in organic apolar solvents. The incorporation of Li + ions in CaF 2 :Eu 3+ does not lead to new crystalline phases. The main diffraction peaks are found to shift to small angles when codoped with 7 mol% Li + , while a reverse shift can be noted with the codoping amount increasing to 9 mol% Li + , indicating that the codoped Li + enables the crystal field environment of Eu 3+ to be changed. The excitation and luminescence intensities of all peaks indexed to Eu 3+ have enhanced apparently when codoped with 7 mol% Li + ions. The lifetime of the 5 D 0 state of Eu 3+ ions is also increased by introducing 7 mol% of Li + ions.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
WATER SCIENCE AND TECHNOLOGY
·
2024
·Vol. 90
·期 1
·32-44
·
IF 2.5
Cao Shuqin,Li Yubiao,Wu Xiaoyong,Li Wanqing,Yang Xu
View large Download slide View large Download slide Close modal Developing a feasible and low-cost strategy for the recovery of calcium fluoride efficiently from fluoride-containing wastewater is very essential for the recycle of fluoride resources. Herein, a modified lime precipitation method was employed to recover CaF 2 from fluorinated wastewater using a special icy lime solution. Intriguingly, the highest F – removal was greater than 95% under the optimal condition, leaving a fluoride concentration from 200 to 8.64 mg/L, while the lime dosage was much lower than that of industry. Importantly, spherical-shaped CaF 2 particles with a 93.47% purity and size smaller than 600 nm were recovered, which has a high potential for the production of hydrofluoric acid. Besides, the precipitation was significantly affected by Ca/F molar ratio, stirring time, temperature, and solution pH. Furthermore, the thermodynamics and kinetics were investigated in detail to reveal the crystallization process. As a result, the defluorination reaction followed the pseudo-second order reaction kinetics model. Also, CO 2 in the air adversely influenced the CaF 2 purity. Based on this facile method, a high lime utilization efficiency was applied to defluorination, which contributed to protecting the environment and saving costs. This study, therefore, provides a feasible approach for the green recovery of fluorine resources and has significance for related research. A facile icy lime precipitation method was employed to remove F − . Highly pure spherical particles with CaF 2 of more than 93% were recovered. Thermodynamics implied that CO 2 had an inhibitory effect on the purity of CaF 2 . Change in F fitted well with the pseudo-second order reaction kinetics model. The co-precipitation of CaF 2 and CaCO 3 occurred.
研究领域:
环境工程
·
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
OPTICAL ENGINEERING
·
2017
·
IF 1.082
Ting Fan,Jiantao Lü,Guoji Li,Yongfa Huang
Polyvinyl pyrrolidone- (PVP) and ethylene glycol- (EG) coated water dispersible mesoporous CaF2:Eu3+,Li+ nanocrystals were synthesized by a simple one-pot hydrothermal method. The role of Li+ ions on the morphology and spectra in the CaF2 nanocrystals have been reported. The synthesized nanocrystals were monodisperse with regular sphere-like shapes and exhibited obvious hollow mesoporous structure. The results from x-ray photoelectron spectroscopy determined the successful incorporation of Eu3+ ions and Li+ ions into the CaF2 host lattice. The excitation and emission intensity of Eu3+ enhanced with Li+ concentration until 7 mol.%. The nanocrystals could disperse in water for more than a month due to the EG and PVP molecules coated over the nanocrystals.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2016
·Vol. 16
·期 4
·3679-3683
·
IF 1.338
Li Suwen,Huang Qingqing,Jiang Yi,Hu Min
A series of Ce3+-Yb3+ co-doped CaF2 nanoparticles were prepared by a hydrothermal synthesis method. The structure, morphology, photoluminescence properties, and fluorescence dynamics were studied systemically. Under the excitation of the 5d level of
Ce3+, an efficient energy transfer from Ce3+ to Yb3+ occurred, and the efficient near-infrared emission at 900–1050 nm matching to the energy of Si band gap of Si-based solar cells was observed. The lifetime of Ce3+ decreased, and the inner
quantum efficiency increased with increasing Yb3+ concentration. The quantum efficiency dependent on Yb3+ concentration was calculated, and the maximum efficiency approached 186%. As a down-conversion luminescent convertor, this kind of material can be used in front of
Si-based solar cells to reduce thermalization loss and enhance conversion efficiency of solar cells.
研究领域:
材料科学
·
光物理学
✓ 已验证
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2025
·
IF 4.2
Jinjie Zheng,Honglie Shen,Yufang Li,Huanlun Tong,Jingzhe Zhang,Zhihong Xie
In this study, a novel fabrication method for a bilayer film consisting of the Bi 2 Mo 3 O 12 :Eu 3+ and CaF 2 was developed. Bi 2 Mo 3 O 12 :Eu 3+ film was prepared using the chemical solution method, eliminating the need for separate phosphor preparation. The excitation spectra of Bi 2 Mo 3 O 12 :Eu 3+ displayed a broad band within the range of 300 and 420 nm. Under ultraviolet (UV) excitation, the material emitted strong red luminescence, with a dominant peak around 615 nm, which coincides with the absorption range of silicon solar cells. Additionally, a CaF 2 anti-reflection layer was introduced to enhance optical transmittance. The average transmittance of the Bi 2 Mo 3 O 12 :Eu 3+ @CaF 2 bilayer film reached 92.3%, representing a 0.7% increase compared to the bare glass substrate (91.6%). As a proof-of-concept, applying Bi 2 Mo 3 O 12 :Eu 3+ @CaF 2 to this bilayer film on photovoltaic modules resulted in an absolute enhancement of 0.19% in power conversion efficiency.
✓ 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）