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Academic literature on the topic 'Fluorapatite'

Author: Grafiati

Published: 4 June 2021

Last updated: 29 January 2023

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Journal articles on the topic "Fluorapatite"

Wang, Xianchen, Qin Zhang, Song Mao, and Wei Cheng. "A Theoretical Study on the Electronic Structure and Floatability of Rare Earth Elements (La, Ce, Nd and Y) Bearing Fluorapatite." Minerals 9, no. 8 (August 20, 2019): 500. http://dx.doi.org/10.3390/min9080500.

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Calcium atoms are often replaced by rare earth elements (REEs) in the lattice of fluorapatite (Ca10F2(PO4)6), making the phosphate ore an important potential rare earth resource. In this paper, the electronic properties of REEs (La, Ce, Nd and Y) bearing fluorapatite crystals have been investigated by density functional theory. Results of calculation indicated that the existence of REEs increased the cell parameters of fluorapatite in varying degrees. The REEs substitution made the Fermi level of fluorapatite to move to higher energy levels, making it easier to accept electrons. Except for Y, all the other REEs (La, Ce and Nd) showed that the electronic state mainly exists in the valence band. The Fermi level of REEs were mainly contributed by La5d, Ce4f, Nd4f and Y4d, respectively. The Mulliken values of REE–F and REE–O bonds in REEs-bearing fluorapatites were larger than those of Ca–F and Ca–O bonds in the perfect crystal, and the values of Y–F and Y–O bonds were the largest. The results of interaction between fluorapatite and oleic acid by frontier molecular orbital analysis suggested that the substitution of REEs can improve the reactivity of fluorapatite with oleic acid.

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Zhang, Jingkun, Zhiyun Xiao, and Hongbo Zhang. "Selective Flotation Behavior of Dolomite from Fluorapatite Using Hydroxy Ethylene Diphosphonic Acid as High-Efficiency Depressant." Minerals 12, no. 12 (December 19, 2022): 1633. http://dx.doi.org/10.3390/min12121633.

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In the reverse flotation of fluorapatite and dolomite, high-efficiency depressors of fluorapatite have received considerable attention. In this paper, the depression mechanism of hydroxy ethylene diphosphonic acid (HEDP) was studied for the first time as a novel fluorapatite depressant on the surface of fluorapatite. The effect of HEDP on the flotation behavior of the two minerals was studied by single and mixed minerals in flotation tests. HEDP exhibited an excellent depression effect on fluorapatite flotation, whereas its adsorption on dolomite surface was minimal. Fluorapatite and dolomite were effectively separated by applying sodium oleate as a collector and HEDP as a depressant at pH 6.0. The depression mechanism of HEDP on fluorapatite was further analyzed via contact angle measurement, zeta potential and X-ray photoelectron spectroscopic (XPS) analysis. We found that HEDP seriously hindered the adsorption of sodium oleate (NaOL) on the fluorapatite surface and had a minimal effect on the dolomite surface. XPS analysis results indicate that the strong adsorption of HEDP on the fluorapatite surface can be attributed to the strong chelation between the electron-rich groups of HEDP and Ca ions on the fluorapatite surface. Therefore, HEDP is used as a selective depressant of fluorapatite in the fluorapatite–dolomite flotation–separation process.

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Ghaemi, Mohammad, Sergiy Sayenko, Volodymyr Shkuropatenko, Anna Zykova, Kateryna Ulybkina, Olena Bereznyak, Andrzej Krupa, and Mirosław Sawczak. "The effect of Sr and Mg substitutions on structure, mechanical properties and solubility of fluorapatite ceramics for biomedical applications." Processing and Application of Ceramics 16, no. 3 (2022): 218–29. http://dx.doi.org/10.2298/pac2203218g.

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Ionic substitutions play important role in the modifications of biological apatites. Recently, the attention has been focused on the co-doping effects on functional properties of apatite based biomaterials. In this research work, the dense samples of fluorapatites, Ca10(PO4)6F2 and Ca8MgSr(PO4)6F2, were produced after sintering at 1250?C for 6 h in air. Structural characterization, carried out with XRD, IR, Raman and SEM, confirmed the formation of dense and homogeneous structure with main fluorapatite and small amount of Ca3(PO4)2 phase. The presented results also demonstrate the stability of structural and mechanical properties of fluorapatites after immersion tests in saline and buffer solutions. The durability of mechanical properties and biocompatibility of the Ca10(PO4)6F2 and Ca8MgSr(PO4)6F2 fluorapatites make these materials highly attractive for biomedical application.

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Kuo, Tsung-Yuan, Chi-Sheng Chien, Cheng-Wei Liu, and Tzer-Min Lee. "Comparative investigation into effects of ZrO2 and Al2O3 addition in fluorapatite laser-clad composite coatings on Ti6Al4V alloy." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 233, no. 2 (December 10, 2018): 157–69. http://dx.doi.org/10.1177/0954411918816113.

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Composite coatings consisting of fluorapatite mixed with 20 wt% yttria (3 mol%) stabilized cubic phase zirconia (c-ZrO2, 3Y-TZP) or 20 wt% alumina (α-Al2O3) were deposited on Ti6Al4V substrates using a Nd:YAG laser cladding system. The interface morphology, phase composition, micro-hardness and biological properties of the two coatings were examined and compared. The results showed that the fluorapatite/Al2O3 specimen underwent a greater inter-diffusion at the interface between the coating layer and the transition layer than the fluorapatite/ZrO2 specimen. During the cladding process, the ZrO2 and Al2O3 components of the coating were completely decomposed or underwent phase transformation. In addition, the fluorapatite was partially decomposed. For both specimens, the coating layers contained fluorapatite, CaF2 and CaTiO3 phases. The coating layer of the fluorapatite/ZrO2 specimen additionally contained TTCP, CaO, CaZrO3 and m-ZrO2 (monoclinic phase), while that of the fluorapatite/Al2O3 specimen contained β-TCP, CaAl2O4 and θ-Al2O3. The average micro-hardness of the fluorapatite/ZrO2 coating layer (1300 HV) was approximately 200 HV higher than that of the fluorapatite/Al2O3 coating layer (1100 HV). Both specimens generated dense bone-like apatite following immersion in simulated body fluid for 3 days. In other words, both specimens had a good in vitro bioactivity. However, the fluorapatite/ZrO2 specimen showed a better initial attachment and spread of osteoblast-like osteosarcoma MG63 cells than the fluorapatite/Al2O3 specimen in in vitro biocompatibility tests performed for 24 h.

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Myšľan, Pavol, Peter Ružička, Tomáš Mikuš, and Miroslav Hain. "3D distribúcia minerálnych inklúzií v granátoch z lokalít Lesné - Potičky a Beňatinská voda (Slovenská republika)." Bulletin Mineralogie Petrologie 28, no. 2 (2020): 246–60. http://dx.doi.org/10.46861/bmp.28.246.

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Visualization of garnets and their mineral inclusions was performed by X-ray microtomography by reconstructing 3D image from 1800 measured 2D X-ray projections. Visualization procedure of 3D distribution of mineral inclusions was based on the different absorption of X-ray radiation between the host garnet and mineral inclusions. 3D visualization provided a realistic picture of a distribution of the 126 identified mineral inclusions in garnet from rhyolite and rhyodacite Beňatinská voda and 21 inclusions in garnet from Lesné - Potičky (Slovak Republic). Composition of garnet from locality Lesné - Potičky is Alm71.0-73.7Prp8.3-9.0Grs14.7-16.6 and from locality Beňatinská voda is Alm72.1-73.2 Prp5.5-5.9Grs18.3-19.4. Mineral inclusions in garnets from locality Lesné - Potičky are represented by fluorapatite, zircon, ilmenite, annite and magmatic melts preserved in the form of glass inclusions trapped in apatite inclusions. Mineral inclusions in garnets from locality Beňatinská voda are represented by fluorapatite, zircon and plagioclase An78.53-57.12. Chemical composition of zircons and fluorapatites are similar from both localities. Based on the chemical composition, the high-pressure origin of garnets associated with I-type magmas was confirmed.

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Gall, Quentin, William J. Davis, David G. Lowe, and Quinn Dabros. "Diagenetic apatite character and in situ ion microprobe U–Pb age, Keeseville Formation, Potsdam Group, New York State." Canadian Journal of Earth Sciences 54, no. 7 (July 2017): 785–97. http://dx.doi.org/10.1139/cjes-2016-0195.

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An occurrence of diagenetic fluorapatite cement is documented within the Cambro-Ordovician Keeseville Formation, Potsdam Group, near Chateaugay in New York State. The fluorapatite cement occurs as stratiform layers within ephemeral fluvial quartz arenites, which have been reworked by aeolian processes prior to burial. The paragenetic sequence includes the following: compaction of dust-rimmed grains → quartz cementation → minor kaolinite → fluorapatite cementation followed by secondary dissolution porosity and telogenetic hematite cementation. Mesogenetic illitization of kaolinite may have taken place prior to or following fluorapatite cementation. The fluorapatite occurs as elongated bladed crystals that characteristically contain ladder-like, inclusion-rich cores running parallel to crystal length, surrounded by clearer rims, and larger blocky crystals towards the middle of interstices. In situ SHRIMP analyses of blocky fluorapatite crystals yield a U–Pb age of 486 ± 29 Ma, indicating that the cement formed during mesogenetic burial processes and (or) during fluid flow driven by Taconic orogenic events. There is no obvious source of phosphorous for the fluorapatite cement within the Potsdam Group, but phosphorous-rich lithologies are known from the adjacent basement of the Adirondack Dome. Phosphorous-rich fluids may have been derived from these basement lithologies. The occurrence of the rare fluorapatite cement in the Keeseville Formation adjacent to the Chateaugay Lake Fault raises the possibility that alkaline phosphatic fluids were focused within the fault and migrated laterally away from the fault into the host Keeseville Formation to form stratiform fluorapatite cement in the sandstone.

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Zheng, Huifang, Yingxin Chen, Xiaoqing Weng, Yanfeng Jin, Richard M. Kasomo, and Shunfu Ao. "Flotation Separation of Dolomite from Fluorapatite Using Sodium Dodecyl Benzene Sulfonate as the Efficient Collector under Low Temperature." Minerals 12, no. 2 (February 10, 2022): 228. http://dx.doi.org/10.3390/min12020228.

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Flotation is the most often employed process to achieve the selective removal of contaminants from the raw materials used in the manufacturing of phosphate fertilizer. However, sodium oleate (NaOL), as a typical collector, is ineffective because of its low collecting ability under low temperature. As a result, developing and implementing feasible alternatives is critical for the long-term output of mines. In this study, sodium dodecyl benzene sulfonate (SDBS), a low-cost and freely soluble reagent under low temperature was used to examine its collecting ability and selectivity in a fluorapatite-dolomite system by means of single and artificially mixed minerals flotation. The adsorption mechanism was evaluated with the help of XPS analyses. The flotation results demonstrate that SDBS could float both fluorapatite and dolomite, but show a higher affinity towards fluorapatite instead of dolomite. Moreover, SDBS could preferred adsorb onto fluorapatite surface when fluorapatite and dolomite coexist. SDBS is more suitable than NaOL for satisfactory recovery of fluorapatite under low temperature in terms of the higher recovery obtained. The XPS analyses results demonstrate that the adsorption of SDBS on fluorapatite surface was more intensively as opposed to that on dolomite surface and Ca active sites on fluorapatite surface are supposed to be the main location for SDBS attachment.

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Thủy, Nguyễn Thị, and Nguyễn Thị Hồng Nụ. "Characteristics of phosphate phase (fluorapatite and monazite) in the South Nam Xe carbonatites, Northwest Vietnam." Hue University Journal of Science: Earth Science and Environment 126, no. 4B (June 2, 2017): 97. http://dx.doi.org/10.26459/hueuni-jese.v126i4b.4293.

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This paper presents characteristics of appearance and mineral chemistry of phosphate phase, including fluorapatite and monazite in the South Nam Xe carbonatite dykes in Northwest Vietnam. These minerals occur in both calcio- and ferrocarbonatites in various modes. Most of the fluorapatites in the calciocarbonatites are oblong to elongated, and have sharp contacts with calcite, aegirine and phlogopite suggesting their primary origin; whereas those in the ferrocarbonatites are commonly present in forms of stubby to perfect hexagonal prismatic crystals, which partly replaced by the monazite. The monazites in the ferrocarbonatites also occur as hundreds micro isolated crystals, which associated with ankerite, feldspar, magnetite and phlogopite.Contents of fluor and rare earth elements (REE) are relatively high (F up to 4.26 wt.%; REE up to 5.19 wt.%) indicating a F- and REE-enriched precipitation for the carbonatites. The enrichment in light REEs in the fluorapatite is paired with an enrichment in Na, varying from 0.25 wt.% to 0.89 wt.%. The replacement of REE and Na for Ca in the fluorapatites, which leads to change in CaO/P2O5 ratios might show an open system where Ca and P are added to areas of the fluorapatite depleted in light REE (LREE). REE contents in the monazite show a very limited variation, and are mainly composed of La, Ce and Nd (La2O3 = 21.09-22.72 wt.%, Ce2O3 = 32.82-33.35 wt.%, Nd2O3 = 6.96-8.20 wt.% in calciocarbonatite; La2O3 = 16.61-17.39 wt.%, Ce2O3 = 32.07-33.52 wt.%, Nd2O3 = 8.92-10.94 wt.% in ferrocarbonatite).

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Tulyaganov, D. U., and R. Ya Khodakovskaya. "Glass-ceramic biomaterials based on the fluorapatite-anorthite and fluorapatitie-diopside systems." Glass and Ceramics 48, no. 5 (May 1991): 221–22. http://dx.doi.org/10.1007/bf00676772.

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Cook, Robert B. "Connoisseurs's Choice: Fluorapatite." Rocks & Minerals 68, no. 2 (April 1993): 112–14. http://dx.doi.org/10.1080/00357529.1993.9926537.

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Dissertations / Theses on the topic "Fluorapatite"

Moorehead, Robert David. "Crystallisation in fluorapatite-fluorphlogopite glass ceramics." Thesis, University of Salford, 2011. http://usir.salford.ac.uk/26825/.

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Apatite based glass-ceramics are some of the most bioactive materials found to date. They do not require fibrous encapsulation and bond to bone directly through an apatite layer. Apatite based glass-ceramics exhibit relatively poor biaxial flexural strength, hence limiting their applications to non-load bearing implants. The addition of mica results in a material that is highly machinable, and provided that a suitable interlocking microstructure can be produced, the strength will be increased. The aim of this work is to investigate how altering the heat treatment affects the crystallisation and the final mechanical properties of three different compositions of glass-ceramic. The glass system studied is the ternary glass system; barium fluorphlogopite (Bao.sMgafSiaAlOiojFz), fluorapatite (CaiofPO^eFz) and cordierite (MgzAUSisOis). The three compositions differ by the mol% of fluorapatite forming feedstock in the precursor glass. Glass-ceramics formed by heat-treating a glassy precursor are investigated using differential scanning calorimetry, kinetic neutron diffraction and scanning electron microscopy. The mechanical properties of the samples are characterised by their biaxial flexural strength and Vickers hardness. The phases formed and the microstructures of the samples are linked to the mechanical properties and an assessment of the final material's implant suitability is made.

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Kansal, Ishu. "Diopside-fluorapatite-wollastonite based bioactive glasses and glass-ceramics." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/14827.

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Doutoramento em Ciência e Engenharia dos Materiais
Bioactive glasses and glass–ceramics are a class of biomaterials which elicit special response on their surface when in contact with biological fluids, leading to strong bonding to living tissue. This particular trait along with good sintering ability and high mechanical strength make them ideal materials for scaffold fabrication. The work presented in this thesis is directed towards understanding the composition-structure-property relationships in potentially bioactive glasses designed in CaOMgOP2O5SiO2F system, in some cases with added Na2O. The main emphasis has been on unearthing the influence of glass composition on molecular structure, sintering ability and bioactivity of phosphosilicate glasses. The parent glass compositions have been designed in the primary crystallization field of the pseudo-ternary system of diopside (CaO•MgO•2SiO2) – fluorapatite (9CaO•3P2O5•CaF2) – wollastonite (CaO•SiO2), followed by studying the impact of compositional variations on the structure-property relationships and sintering ability of these glasses. All the glasses investigated in this work have been synthesized via melt-quenching route and have been characterized for their molecular structure, sintering ability, chemical degradation and bioactivity using wide array of experimental tools and techniques. It has been shown that in all investigated glass compositions the silicate network was mainly dominated by Q2 units while phosphate in all the glasses was found to be coordinated in orthophosphate environment. The glass compositions designed in alkali-free region of diopside – fluorapatite system demonstrated excellent sintering ability and good bioactivity in order to qualify them as potential materials for scaffold fabrication while alkali-rich bioactive glasses not only hinder the densification during sintering but also induce cytotoxicity in vitro, thus, are not ideal candidates for in vitro tissue engineering. One of our bioglass compositions with low sodium content has been tested successfully both in vivo and in preliminary clinical trials. But this work needs to be continued and deepened. The dispersing of fine glass particles in aqueous media or in other suitable solvents, and the study of the most important factors that affect the rheology of the suspensions are essential steps to enable the manufacture of porous structures with tailor-made hierarchical pores by advanced processing techniques such as Robocasting.
Os vidros e vitrocerâmicos bioactivos são uma classe de biomateriais que induzem uma resposta especial à sua superfície quando em contacto com fluidos biológicos que conduz a uma forte ligação ao tecido vivo. Esta característica particular conjugada com uma boa aptidão para a sinterização e elevada resistência mecânica torna estes materiais ideais para a fabricação de estruturas de suporte à regeneração óssea. O trabalho apresentado nesta tese pretende dar um contributo para uma melhor compreensão das relações entre composição-estrutura-propriedades em vidros potencialmente bioactivos com composições no sistema CaOMgOP2O5SiO2F, em alguns casos com a adição de Na2O. O estudo da influência exercida pela composição do vidro na estrutura molecular, capacidade de sinterização e nível de bioactividade dos vidros fosfosilicatados foi objecto de especial atenção. As composições vítreas foram concebidas no campo da cristalização primária do pseudo sistema ternário do diópsido (CaO•MgO•2SiO2) – fluorapatite (9CaO•3P2O5•CaF2) – wollastonite, e estudou-se o impacto das variações composicionais na estrutura, nas propriedades e na capacidade de sinterização destes vidros. Todos os vidros investigados neste trabalho foram preparados por fusão e fritagem e caracterizados quanto à sua estrutura molecular, capacidade de sinterização, degradação química e bioactividade, usando uma grande variedade de técnicas experimentais. Ficou demonstrado que em todas as composições de vidro investigadas a rede de silicato era dominada principalmente por unidades Q2 enquanto o fosfato se encontrava coordenado em ambiente de ortofosfato. As composições de biovidros isentas de alcalinos do sistema diópsido–fluorapatite demonstram possuir excelente capacidade de sinterização e elevados níveis de bioactividade, atributos que os qualificam como materiais promissores para a fabricação de estruturas de suporte à regeneração de tecidos ósseos, enquanto os vidros bioactivos contendo alcalinos foram mais difíceis de densificar durante a sinterização e induziram citotoxicidade in vitro, não sendo candidatos ideais para a engenharia de tecidos. Uma das nossas composições de biovidro com um baixo teor de sódio foi testada com sucesso tanto in vivo como em ensaios clínicos preliminares. Mas este trabalho precisa de ser continuado e aprofundado. A dispersão de fritas moídas em meio aquoso ou outros solventes adequados, e o estudo dos factores mais relevantes que condicionam a reologia das suspensões são etapas essenciais para viabilizar o processo de fabrico de suportes porosos com estruturas hierárquicas de poros feitas por medida através de técnicas de processamento avançadas tais como o Robocasting.

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Jarlbring, Mathias. "Surface reactions in aqueous suspensions of fluorapatite and iron oxides /." Luleå : Luleå University of Technology, 2006. http://epubl.ltu.se/1402-1544/2006/05/index.html.

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Al-Taie, Asmaa Mohammed Basil Jasim. "Development and characterisation of novel fluorapatite containing dental composite materials." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/17910/.

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Objectives: The objectives of this study were to develop model dental composites incorporating fluorapatite (FA) as secondary filler and to characterise their physical and mechanical properties and fluoride ion release. Methods: Experimental composites were formulated containing BisGMA/TEGDMA/BisEMA and barium aluminium silicate glass as the primary filler. FA rod-like crystals and bundles were synthesised using a hydrothermal method and incorporated at 0 (0FA), 10 (10FA), 20 (20FA), 30 (30FA) and 40% (40FA) by mass into the previously identified optimum experimental composite, maintaining an overall filler content of 80%wt. 0FA and TetricEvoCeram (TC) were used for comparison as the experimental and the commercial controls, respectively. Two-body wear, Vickers Hardness (HV), Degree of Conversion (DC), Flexural strength (FS), Flexural modulus (FM), Fracture Toughness (K1C) and fluoride ion release were measured for each composition. Quantitative analysis of wear volume was carried out using a noncontact profilometer. Qualitative imaging of wear and fracture surfaces was undertaken using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). Statistical analysis was conducted using SPSS version 21. Results: All experimental composites showed similar wear resistance (p > 0.05) and enhanced microhardness compared to TC (p < 0.05). DC for all composites ranged between 56-60% at 20s polymerisation (p > 0.05). FA composites showed higher FM (p < 0.05) and similar FS (p > 0.05) to TC but lower FM and FS when compared to 0FA. 30FA and 40FA showed similar K1C to TC and 0FA (p > 0.05), whereas 10FA and 20FA showed lower K1C when compared to the other groups (p < 0.05). Under neutral pH, no fluoride release was detected from FA containing composites. However, under acidic conditions (pH 4), FA containing composites released fluoride when compared to the controls (p < 0.05), the amount of which was proportional to the amount of FA incorporated within the samples, i.e. 40FA> 30FA > 20FA > 10FA (p < 0.05). Conclusions: Experimental dental composites were successfully produced incorporating FA as secondary filler. The addition of FA did not affect the key physical and mechanical properties when compared to the commercial control. FA composites showed short and long term fluoride release under acidic conditions showing a promising step towards a potential “smart” fluoride releasing dental composite.

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Selvaratnam, Prashant. "Radiation damage and plutonium solid-solubility in fluorapatite nuclear waste forms." Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708106.

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Tredwin, C. J. "Sol-gel derived hydroxyapatite, fluorhydroxyapatite and fluorapatite coatings for titanium implants." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/18785/.

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Currently, most titanium implant coatings are made using hydroxyapatite and a plasma-spraying technique. There are however limitations associated with the plasma-spraying process including; poor adherence, high porosity and cost. An alternative - the sol-gel technique offers many potential advantages but is currently lacking research data for this application. Hydroxyapatite (HA), fluorhydroxyapatite (FHA) and fluorapatite (FA) have been synthesised by a sol-gel method. Calcium nitrate and triethyl phosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride (NH4F) were incorporated for the preparation of the FHA and FA sol-gels. Optimisation and characterisation of the sol-gels was carried out using, X-ray Diffraction (XRD), High Temperature X-Ray Diffraction (HTXRD), Fourier Transform Infrared Analysis (FTIR) and Differential Thermal Analysis (DTA). Rheology and hydrophilicity of the sol-gels showed that increasing fluoride ion substitution caused an increase in viscosity and contact angle. The dissolution (Ca2+ and PO4 3-rates) rates of the fluoride-substituted powders from the sol-gels were considerably lower than that of HA and all rates could be decreased by increasing the sintering temperature. This suggests the possibility of tailoring the solubility of any coatings made from the sol-gels through fluoride ion substitution and increased sintering temperature. A spin coating protocol has been established for coating the sol-gels onto titanium. Increasing the coating speed decreased the porosity and thickness of the coatings. Bond strengths to titanium were investigated. Fluoride substitution and sintering temperature were shown to be important factors. Cellular proliferation studies revealed that increasing the level of fluoride substitution in the apatite structure significantly increased the biocompatibility of the material. The sol-gel technique may be an alternative to plasma spraying for coating titanium implants. Furthermore it may also be suitable for producing HA, FHA and FA as bone grafting materials.

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Jarlbring, Mathias. "Characterisation and surface reactions of iron oxides and fluorapatite in aqueous suspensions." Licentiate thesis, Luleå, 2004. http://epubl.luth.se/1402-1757/2004/02.

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Chappell, Joseph Caleb. "CHEMICAL AND STRUCTURAL CHARACTERIZATION OF FLUORAPATITE FROM THE POUDRETTE PEGMATITE, MONT SAINT-HILAIRE, QUEBEC, CANADA." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1547221806721972.

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Bandara, A. M. T. S. "Comparative solubility and leaching studies relevant to hydrometallurgical processing of rare earth phosphate concentrates containing fluorapatite." Thesis, Bandara, A.M.T.S. (2017) Comparative solubility and leaching studies relevant to hydrometallurgical processing of rare earth phosphate concentrates containing fluorapatite. PhD thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/38248/.

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Highly technological applications and scarcity of supply have inspired the recovery of rare earth elements (REEs) from various resources. Many rare earth phosphate mineral concentrates are associated with fluorapatite (FAP). An acid pre-leach is required to selectively leach the FAP fraction as calcium salts, phosphoric acid and hydrofluoric acid prior to the sulphuric acid digestion to avoid the interference of calcium and other impurities in the downstream processing steps of the acid baked product, rich in REEs. Hence, investigation of the dissolution kinetics of FAP and solubility of trivalent rare earth metal ions and other major and minor impurities in different acid-sulphate solutions systems are important areas of current research. This thesis focused on (i) the solubility of REEs using pure perchlorate/sulphate and mixed RE-carbonate salts in acid-salt mixtures and synthetic process liquors and (ii) dissolution kinetics of phosphate, fluoride and major, minor and trace metal ions from a rotating disc of FAP and particles of FAP and a RE-phosphate concentrate. The strong and weak acids tested included perchloric, hydrochloric, sulphuric, nitric and phosphoric acids as well as weak organic acids. The feed materials, leach liquors and residues were characterized using standard analytical methods and the results were explained on the basis of reaction stoichiometry, equilibria and kinetic models. The main findings from the solubility studies are: (i) the precipitation of hydrated RE(III)-sulphate and Na-RE(III)-sulphate salts in different solution media, (ii) the formation of sulphate complexes of RE(III), aluminium and iron(III) based on Raman spectroscopic studies, and (iii) the negative impact of high pH and high temperature on the solubility of REEs in sulphate media. The rotating disc dissolution of FAP and particle leaching of FAP and RE-phosphate concentrate highlighted that the FAP dissolution is affected by the proton activity and the association of calcium ions with anions to form complex species and insoluble product layers, which in turn affect the diffusion or chemically controlled dissolutions of cations and anions from FAP and the phosphate concentrate. The comparative study based on different acid concentrations, temperatures and pulp density showed the advantages of using phosphoric acid for pre-leaching FAP from the phosphate concentrate to minimize REE leaching. Keywords: Rare earth phosphate, natural fluorapatite, characterization, acid pre-leach, solubility, complex species, kinetic models

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ALVES, Luana Cristina Feitosa. "Estudo da influência do fluoreto de cálcio na bioatividade de vidros borato." Universidade Federal do Maranhão, 2017. https://tedebc.ufma.br/jspui/handle/tede/tede/1939.

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Bioactive borate glass has presented superior results then bioactive silicate glasses, when compared its conversion rates in apatite and its potential of bioactivity. In this work, new Borate glasses with the basic 60B2O3 - 4P2O5 - 18Na2O – xCaF2 – (18-xCaO), com x = 0, 5 e 10 % wt were synthesized, and investigated the influence of CaF2 addition on bioactivity of samples in vitro, in a period of 28 days in a simulator of the body fluid (SBF). This bioactivity was investigated by means of X-ray diffraction (DRX), Raman Spectroscopy, FTIR and by the measure of pH. DRX measures, prior to immersion, presented wide bands, evidencing the amorphous structure of glasses. The results of density, thermal analysis, XRD, Raman and FTIR show that the addition of CaF2, until 10 % wt, did not cause significant changes in samples network structure. The thermal stability for all samples was calculated from DSC data and all presented values up to 120°C. The results of pH of SBF solution show increase from for 24 hours, which contributes to the dissolution of the outermost layer of the glass and the precipitation of apatite. In XRD data for 60B sample soaked in SBF for 7 days, there was formation of crystalline peaks, at 26° and 32° (2ϴ), in all measures. These peaks correspond to patterns of hydroxyapatite (HA). The XRD spectra in 60B5CaF and 60B10CaF, soaked in SBF for 7 days, presented peaks in 28°(2ϴ) corresponding to fluorapatite (FA), due to the presence of CaF2 in these glasses. Raman and FTIR measurements confirmed what was measured by XRD, showing characteristic peaks of HA and FA for all the samples. Results show that the prepared samples present potential for being used as biomaterials in biomedical applications, such as orthopedics, dentistry and tissue engineering.
Vidros boratos bioativos têm apresentado resultados superiores aos vidros silicatos bioativos, quando comparamos suas taxas de conversão em apatita e seu potencial de bioatividade. Neste trabalho sintetizamos novos vidros boratos com a composição básica 60B2O3 - 4P2O5 - 18Na2O – xCaF2 – (18-xCaO), com x = 0, 5 e 10 % em massa, e investigamos a influência da adição de CaF2 na bioatividade das amostras in vitro, em um período de 28 dias, em um simulador do fluído corporal (SBF). As medidas de DRX, antes da imersão, apresentaram bandas largas, comprovando a estrutura amorfa dos vidros. E verificou-se por meio das análises de Densidade, análise térmica, DRX, Raman e FTIR, que a adição de CaF2 até 10%, em massa, não provocou grandes mudanças estruturais na amostras. Por meio da calorimetria exploratória diferencial, determinamos a estabilidade térmica dos vidros que apresentaram valores acima de 120°C. A bioatividade foi investigada por meio das técnicas de difração de raios-X (DRX), espectroscopia Raman e FTIR, e pela medida do pH da solução SBF. Os resultados obtidos mostraram que, em 24h, houve um aumento no pH da solução SBF, o que contribui para a dissolução da camada mais externa do vidro e sua conversão em apatita. Nos difratogramas (DRX) para as amostras imersas por 7 dias, houve a formação de picos cristalinos, em 26° e 32° (2ϴ), em todas as amostras medidas. Esses picos correspondem aos padrões de hidroxiapatita. A presença de CaF2 na composição das amostras imersas por 7 dias apresentou picos em 28° (2ϴ) correspondendo a fluorapatita. A intensidade destes picos apresentou um aumento em função do tempo de imersão, durante todo período estudado. As medidas de Raman confirmaram os resultados do DRX, apresentando para todas as amostras espectros característicos da hidroxiapatita em 960 cm-1 . As amostras preparadas com CaF2 apresentaram picos em 965 cm-1 , que corresponde a fluorapatita. O FTIR confirmou os resultados apresentados no DRX e Raman, em que todas as amostras apresentaram um pico centrado em 1041 cm-1 para a hidroxiapatita e 1042 cm-1 característico para a fluorapatita. Os resultados demonstram que as amostras preparadas apresentam potencial para serem usados como biomateriais em aplicações biomédicas, como ortopedia, odontologia e engenharia de tecidos.

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Book chapters on the topic "Fluorapatite"

Chow, Laurence C., and Milenko Markovic. "Physicochemical Properties of Fluorapatite." In Calcium Phosphates in Biological and Industrial Systems, 67–83. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5517-9_4.

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Fong, Shirley K., Lee A. Gerrard, Brian L. Metcalfe, and Ian W. Donald. "Immobilization of Hafnium Surrogates in Fluorapatite." In Advances in Science and Technology, 2018–23. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/3-908158-01-x.2018.

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Kalinichenko, Elena A., Aleksandr B. Brik, Valentin V. Radchuk, Olga V. Frank-Kamenetskaya, and Oleksii Dubok. "Computer Simulation of Defects in Carbonate Fluorapatite and Hydroxyapatites." In Lecture Notes in Earth System Sciences, 461–77. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-24987-2_35.

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Denissen, H. W., H. M. De Nieuport, W. Kalk, H. G. Schaeken, and A. Van Den Hooff. "Fluorapatite and Hydroxyapatite Heat-Treated Coatings for Dental Implants." In Bioceramics and the Human Body, 130–40. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2896-4_17.

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Zimehl, R., S. F. Willigeroth, M. Hannig, and H. Frahm. "Nano-sized fluorapatite particles by controlled precipitation from heterogeneous systems." In Mesophases, Polymers, and Particles, 110–18. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/b100311.

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Kalinichenko, Elena A., Aleksandr B. Brik, Valentin V. Radchuk, Olga V. Frank-Kamenetskaya, and Oleksii Dubok. "Erratum to: Computer Simulation of Defects in Carbonate Fluorapatite and Hydroxyapatites." In Lecture Notes in Earth System Sciences, E1. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-24987-2_41.

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Gunduz, Oguzhan, S. Salman, S. Kayali, Gultekin Goller, I. Goker, Simeon Agathopoulos, L. S. Ozyegin, and Faik N. Oktar. "Improvement of Microstructure of Bovine Hydroxyapatite (BHA) with Machineable Fluorapatite Glass (MFG)." In Bioceramics 20, 495–98. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-457-x.495.

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Goller, Gultekin, Can Cekli, Ipek Akin, and Erdem Demirkesen. "In-Vitro Bioactivity Characterization of Sodium-Potassium Mica and Fluorapatite Containing Glass Ceramics." In Key Engineering Materials, 185–88. Stafa: Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-422-7.185.

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Holmgren, Allan, Willis Forsling, and Liuming Wu. "An FT-IR Study of Alizarin Red S Adsorbed at the Fluorapatite-Water Interface." In Progress in Fourier Transform Spectroscopy, 197–99. Vienna: Springer Vienna, 1997. http://dx.doi.org/10.1007/978-3-7091-6840-0_31.

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Hill, Robert G., Adam Calver, Stephen Skinner, Adam Stamboulis, and Robert V. Law. "A MAS-NMR and Combined Rietveldt Study of Mixed Calcium/Strontium Fluorapatite Glass-Ceramics." In Bioceramics 18, 305–8. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-992-x.305.

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Conference papers on the topic "Fluorapatite"

Bonner, Jr., Carl E., Chahn C. Chess, Chandana Meegoda, Sennay Stefanos, George B. Loutts, and George E. Miller III. "Raman spectroscopic study of barium fluorapatite." In Optoelectronics '99 - Integrated Optoelectronic Devices, edited by Kathleen I. Schaffers and Lawrence E. Myers. SPIE, 1999. http://dx.doi.org/10.1117/12.349236.

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Payne, Stephen A., William F. Krupke, Larry K. Smith, Laura D. DeLoach, and Wayne L. Kway. "Laser Properties of Yb-doped Fluorapatite." In Advanced Solid State Lasers. Washington, D.C.: OSA, 1992. http://dx.doi.org/10.1364/assl.1992.dl14.

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Arzakantsyan, M., J. Akiyama, Y. Sato, and T. Taira. "Optical Characterization of Yb Doped Fluorapatite Anisotropic Ceramics." In Advanced Solid State Lasers. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/assl.2013.am1a.4.

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Loutts, G. B., C. Bonner, C. Meegoda, H. Ries, M. A. Noginov, N. Noginova, M. Curley, P. Venkateswarlu, A. Rapaport, and M. Bass. "Neodymium Doped Barium Fluorapatite: A New Efficient Laser Material." In Advanced Solid State Lasers. Washington, D.C.: OSA, 1997. http://dx.doi.org/10.1364/assl.1997.sc8.

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Zhu, Yaxin, Chunhua Bai, and Guanghui Li. "Effect of initial pH value and atmosphereon fluorapatite preparation." In 2021 3rd International Academic Exchange Conference on Science and Technology Innovation (IAECST). IEEE, 2021. http://dx.doi.org/10.1109/iaecst54258.2021.9695723.

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Nuzulia, Nur Aisyah, Yessie Widya Sari, and Desi Riah Sari. "Synthesis of Duck Eggshells-based Fluorapatite by Using Microwave Irradiation." In 2018 1st International Conference on Bioinformatics, Biotechnology, and Biomedical Engineering (BioMIC). IEEE, 2018. http://dx.doi.org/10.1109/biomic.2018.8610626.

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Singer, Jared W., and Marian V. Lupulescu. "REE-RICH FLUORAPATITE TEXTURES FROM EASTERN ADIRONDACK IRON ORE DEPOSITS." In 51st Annual Northeastern GSA Section Meeting. Geological Society of America, 2016. http://dx.doi.org/10.1130/abs/2016ne-272533.

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Chappell, J. Caleb, and John Rakovan. "UNIQUE CRYSTAL CHEMICAL ASPECTS OF FLUORAPATITE FROM MONT SAINT-HILAIRE." In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-317652.

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Singh, Abhas, Aravinth Ekamparam, and Surya Sujathan. "Kinetics of Transformation of Calcite to Fluorapatite Under Flow Conditions." In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.8017.

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Peng, Kai, Jinhua Li, peng zou, Qinhan Zhang, and Yue Wang. "Synthesis and luminescent properties of rare earth doped upconversion nano-fluorapatite." In CIOP100, edited by Yue Yang. SPIE, 2018. http://dx.doi.org/10.1117/12.2506547.

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Reports on the topic "Fluorapatite"

Bayramian, Andrew J. Development of Trivalent Ytterbium Doped Fluorapatites for Diode-Pumped Laser Applications. Office of Scientific and Technical Information (OSTI), June 2000. http://dx.doi.org/10.2172/791656.

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Desbarats, A. J., and J. B. Percival. Hydrogeochemistry of mine tailings from a carbonatite-hosted Nb-REE deposit, Oka, Quebec, Canada. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331256.

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Environmental impacts associated with the mining of carbonatite deposits are an emerging concern due to the demand for critical metals. This study investigates the chemistry of tailings seepage at the former Saint Lawrence Columbium mine near Oka, Québec, Canada, which produced pyrochlore concentrate and ferroniobium from a carbonatite-hosted Nb-REE deposit. Its objectives are to characterize the mineralogy of the tailings and their pore water and effluent chemistries. Geochemical mass balance modeling, constrained by aqueous speciation modeling and mineralogy, is then used to identify reactions controlling the chemical evolution of pore water along its flow path through the tailings impoundment. The tailings are composed mainly of REE-enriched calcite (82 wt. %), biotite (12 wt. %) and fluorapatite (4 wt. %). Minor minerals include chlorite, pyrite, sphalerite, molybdenite and unrecovered pyrochlore. Secondary minerals include gypsum, barite and strontianite. Within the unsaturated zone, pore water chemistry is controlled by sulfide oxidation and calcite dissolution with acid neutralization. With increasing depth below the water table, pore water composition reflects gypsum dissolution followed by sulfate reduction and FeS precipitation driven by the oxidation of organic carbon in the tailings. Concomitantly, incongruent dissolution of biotite and chlorite releases K, Mg, Fe, Mn, Ba and F, forming kaolinite and Ca-smectite. Cation exchange reactions further remove Ca from solution, increasing concentrations of Na and K. Fluoride concentrations reach 23 mg/L and 8 mg/L in tailings pore water and effluent, respectively. At a pH of 8.3, Mo is highly mobile and reaches an average concentration of 83 µg/L in tailings effluent. Although U also forms mobile complexes, concentrations do not exceed 16 µg/L due to the low solubility of its pyrochlore host. Adsorption and the low solubility of pyrochlore limit concentrations of Nb to less than 49 µg/L. Cerium, from calcite dissolution, is strongly adsorbed although it reaches concentrations (unfiltered) in excess of 1 mg/L and 100 µg/L in pore water and effluent, respectively. Mine tailings from carbonatite deposits are enriched in a variety of incompatible elements with mineral hosts of varying reactivity. Some of these elements, such as F and Mo, may represent contaminants of concern because of their mobility in alkaline tailings waters.

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