Physics and Chemistry of Minerals最新文献

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Temperature and pressure effects on the structural and vibrational properties of forsterite from density functional theory studies 从密度泛函理论研究看温度和压力对绿柱石结构和振动特性的影响
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-08-08 DOI: 10.1007/s00269-024-01287-4
Sha Chen, Udo Becker
{"title":"Temperature and pressure effects on the structural and vibrational properties of forsterite from density functional theory studies","authors":"Sha Chen,&nbsp;Udo Becker","doi":"10.1007/s00269-024-01287-4","DOIUrl":"10.1007/s00269-024-01287-4","url":null,"abstract":"<div><p>Due to experimental challenges and computational complexities, limited research has explored high-temperature and high-pressure conditions on mineral vibrations. This study employs the quasi-harmonic approximation (QHA) and density functional theory (DFT) to investigate the impact of temperature and pressure on the structural properties and infrared and Raman vibrational modes of forsterite. The computational process involves determining lattice parameters, optimizing the internal crystal structure, and calculating IR and Raman spectra at various temperature and pressure values, both separately and combined. Results highlight significant anisotropy in forsterite, with the b-axis being most sensitive to temperature and pressure, followed by the c-axis, while the a-axis exhibits greater stiffness. The positions of vibrational modes typically shift to higher frequencies with increasing pressure (average shift of 2.70 ± 1.30 cm<sup>−1</sup>/GPa) or to lower frequencies with increasing temperature (average shift of − 0.017 ± 0.018 cm<sup>−1</sup>/K). Modes associated with SiO<sub>4</sub> stretching and bending are less affected by temperature or pressure than translational and rotational modes. A brief investigation into isotope and chemical substitution, as well as cation distribution, in the solid solution (Mg, Fe)<sub>2</sub>SiO<sub>4</sub> reveals lower wavenumbers in fayalite modes compared to forsterite modes, attributed to the heavier Fe mass and larger cell parameters. This study establishes a methodology for computing vibrational frequencies under simultaneous temperature and pressure and emphasizes the significant impact of various factors on vibrational modes. Caution is advised when using vibrational modes for identifying compositions within solid solutions.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141929260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Characterization of the lattice preferred orientation of hcp iron transformed from the single-crystal bcc phase in situ at high pressures up to 80 GPa 在高达 80 GPa 的高压下,由单晶 bcc 相原位转变而来的 hcp 铁的晶格优选取向表征
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-08-05 DOI: 10.1007/s00269-024-01293-6
Yohan Park, Tatsuya Wakamatsu, Shintaro Azuma, Yu Nishihara, Kenji Ohta
{"title":"Characterization of the lattice preferred orientation of hcp iron transformed from the single-crystal bcc phase in situ at high pressures up to 80 GPa","authors":"Yohan Park,&nbsp;Tatsuya Wakamatsu,&nbsp;Shintaro Azuma,&nbsp;Yu Nishihara,&nbsp;Kenji Ohta","doi":"10.1007/s00269-024-01293-6","DOIUrl":"10.1007/s00269-024-01293-6","url":null,"abstract":"<div><p>Studying the anisotropic physical properties of hexagonal closed-packed (hcp) iron is essential for understanding the properties of the Earth’s inner core related to the preferred orientation of the inner core materials suggested by seismic observations. Investigating the anisotropic physical properties of hcp iron requires (1) the synthesis of hcp iron samples that exhibit several distinctive types of strong lattice preferred orientation (LPO) and (2) the quantitative LPO analysis of the samples. Here, we report the distinctive LPO of hcp iron produced from single-crystal body-centered cubic (bcc) iron compressed along three different crystallographic orientations ([100], [110], and [111]) in a diamond anvil cell based on synchrotron multiangle X-ray diffraction measurements up to 80 GPa and 300 K. The orientation relationships between hcp iron and bcc iron are consistent with the Burgers orientation relationship with variant selection. We show that the present method is a way to synthesize hcp iron with strong and characteristic LPO, which is beneficial for experimentally evaluating the anisotropic physical properties of hcp iron.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00269-024-01293-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The thermal expansion of Ti-substituted CaAl12O19 钛取代 CaAl12O19 的热膨胀率
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-08-05 DOI: 10.1007/s00269-024-01286-5
Paul F. Schofield, Andrew J. Berry, Patricia M. Doyle, Kevin S. Knight
{"title":"The thermal expansion of Ti-substituted CaAl12O19","authors":"Paul F. Schofield,&nbsp;Andrew J. Berry,&nbsp;Patricia M. Doyle,&nbsp;Kevin S. Knight","doi":"10.1007/s00269-024-01286-5","DOIUrl":"10.1007/s00269-024-01286-5","url":null,"abstract":"<div><p>CaAl<sub>12</sub>O<sub>19</sub>, which can incorporate Ti as both Ti<sup>3+</sup> and Ti<sup>4+</sup> (charge coupled substitution with Mg<sup>2+</sup>), is one of the first minerals to condense from a gas of solar composition and is used as a ceramic. It is variously known as hibonite, calcium hexaluminate (CaO.6Al<sub>2</sub>O<sub>3</sub>), and CA<sub>6</sub>. The lattice parameters and unit cell volumes of Ti-substituted hibonite (<i>P</i>6<sub>3</sub>/<i>mmc</i>) with the formulae CaAl<sub>11.8</sub>Ti<sup>3+</sup><sub>0.2</sub>O<sub>19</sub> and CaAl<sub>9.8</sub>Ti<sup>3+</sup><sub>0.54</sub>Mg<sub>0.83</sub>Ti<sup>4+</sup><sub>0.83</sub>O<sub>19</sub> were determined as a function of temperature from ~ 10 to 275 K by neutron powder diffraction. The thermal expansion is highly anisotropic with the expansion in <i>c</i> a factor of ~ 5 greater than that in <i>a</i>. The change in <i>a</i> is approximately equal for the two compounds whereas the change in <i>c</i> is almost 50% larger for CaAl<sub>11.8</sub>Ti<sup>3+</sup><sub>0.2</sub>O<sub>19</sub>. CaAl<sub>11.8</sub>Ti<sup>3+</sup><sub>0.2</sub>O<sub>19</sub> also exhibits negative thermal expansion between 10 and 70 K. The change in unit cell volume with temperature of both compositions is well described by a two term Einstein expression. The large change in <i>c</i> is consistent with substitution of Ti onto the M2 and M4 sites of the R-block structural unit.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00269-024-01286-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141944977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Influence of grain size and plastic deformation on the phase transformation of enstatite: insights from microstructures produced during the back-transformation of protoenstatite to clinoenstatite 晶粒尺寸和塑性变形对恩氏铁锂辉石相变的影响:从原恩氏铁锂辉石向克氏铁锂辉石逆变过程中产生的微观结构中获得的启示
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-08-05 DOI: 10.1007/s00269-024-01294-5
Miki Tasaka, Maya Iwago
{"title":"Influence of grain size and plastic deformation on the phase transformation of enstatite: insights from microstructures produced during the back-transformation of protoenstatite to clinoenstatite","authors":"Miki Tasaka,&nbsp;Maya Iwago","doi":"10.1007/s00269-024-01294-5","DOIUrl":"10.1007/s00269-024-01294-5","url":null,"abstract":"<div><p>Enstatite (Mg<sub>2</sub>Si<sub>2</sub>O<sub>6</sub>) is a member of the pyroxene group and an important mineral in the lower crust and upper mantle. Enstatite has three phases at ambient pressure: protoenstatite, orthoenstatite, and clinoenstatite. Previously, the polymorphic transformation of pyroxene has been characterized using bulk techniques such as X-ray diffraction of powders. Given that rocks are crystal aggregates, it is important to use aggregates to understand phase transformations. We therefore conducted grain growth and deformation experiments using aggregates of enstatite to investigate phase transformations. Grain growth experiments were conducted at temperatures (<i>T</i>) of 1345 and 1360 °C under a vacuum of ≈ 10 Pa using an alumina tube furnace. Deformation experiments were conducted at <i>T</i> = 1310 °C and room pressure, a strain rate of ≈ 10<sup>–4</sup> s<sup>–1</sup>, and a resulting stress of ≈ 150 MPa. The samples were analyzed using a scanning electron microscope, electron backscatter diffraction (EBSD), and X-ray diffraction. The results indicate that the grain size affects the transformation from protoenstatite to clinoenstatite, whereas deformation by diffusion creep does not. The EBSD analyses show that the volume fraction of clinoenstatite increases with increasing grain size. The samples underwent diffusion creep during the deformation experiments, and there were no distinct microstructural differences between deformed and undeformed samples. The EBSD analyses show that the transformed clinoenstatite has a characteristic twin structure with a misorientation angle of 180° and a rotation axis of [100] or [001]. Grain sizes become smaller during the phase transformation, even if the mechanism can be characterized as a second-order transformation.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00269-024-01294-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141945026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Crystallographic mechanism of the elastic behaviour of synthetic bütschliite K2Ca(CO3)2 on compression to 20 GPa 压缩至 20 GPa 时合成菱镁矿 K2Ca(CO3)2 弹性行为的晶体学机制
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-07-28 DOI: 10.1007/s00269-024-01291-8
Anna Yu. Likhacheva, Alexandr V. Romanenko, Sergey V. Rashchenko, Sofija Miloš, Paolo Lotti, Ronald Miletich, Anton Shatskiy
{"title":"Crystallographic mechanism of the elastic behaviour of synthetic bütschliite K2Ca(CO3)2 on compression to 20 GPa","authors":"Anna Yu. Likhacheva,&nbsp;Alexandr V. Romanenko,&nbsp;Sergey V. Rashchenko,&nbsp;Sofija Miloš,&nbsp;Paolo Lotti,&nbsp;Ronald Miletich,&nbsp;Anton Shatskiy","doi":"10.1007/s00269-024-01291-8","DOIUrl":"10.1007/s00269-024-01291-8","url":null,"abstract":"<div><p>Bütschliite, K<sub>2</sub>Ca(CO<sub>3</sub>)<sub>2</sub>, occurring as inclusions in mantle minerals, is regarded as one of the key phases to understand phase relationships of dense potassium carbonates and thus to evaluate their potential role within the Earth’s deep carbon cycle. Accordingly, the high-pressure behavior of synthetic bütschliite has been investigated by in-situ single-crystal X-ray diffraction under isothermal compression up to 20 GPa at <i>T</i> = 298 K. The compression mechanism before and after the trigonal-to-monoclinic (<i>R</i>-3<i>m</i> to <i>C</i>2/<i>m</i>) phase transition at ∼6 GPa, found previously, is characterized in terms of the evolution of the cation polyhedra and carbonate groups. On this basis, the modulation of the axial compression is interpreted, and the contribution of the cation polyhedra into the bulk compression is estimated. The refined compressibility of the monoclinic phase (<i>K</i><sub>0</sub> = 44(2) GPa) fits to the trend of the carbonate bulk modulus <i>versus</i> average non-carbon cation radius. The analysis of the obtained and literature structural data suggests the distortion of a large cation polyhedron to be an effective tool to strengthen the carbonate structure at high pressure. On the other hand, the observed symmetrization of the cation polyhedra in trigonal bütschliite is apparently a crucial factor of its stabilization at high pressure upon the temperature rise observed previously. The structural crystallography provided in this study supports the enhanced stability of trigonal bütschliite at high <i>P</i>,<i> T</i> conditions and its significance of being considered as a constituent of the inclusions in deep minerals.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00269-024-01291-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
High-pressure structural behavior of α-K2Ca3(CO3)4 up to 20 GPa 高达 20 GPa 的 α-K2Ca3(CO3)4 高压结构行为
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-07-28 DOI: 10.1007/s00269-024-01292-7
Mark A. Ignatov, Sergey V. Rashchenko, Anna Yu Likhacheva, Alexandr V. Romanenko, Anton F. Shatskiy, Anton V. Arefiev, Konstantin D. Litasov
{"title":"High-pressure structural behavior of α-K2Ca3(CO3)4 up to 20 GPa","authors":"Mark A. Ignatov,&nbsp;Sergey V. Rashchenko,&nbsp;Anna Yu Likhacheva,&nbsp;Alexandr V. Romanenko,&nbsp;Anton F. Shatskiy,&nbsp;Anton V. Arefiev,&nbsp;Konstantin D. Litasov","doi":"10.1007/s00269-024-01292-7","DOIUrl":"10.1007/s00269-024-01292-7","url":null,"abstract":"<div><p>K-Ca double carbonates recently identified in inclusions in diamonds, as well as associated alkali-carbonate melts can play an important role in the deep carbon cycle. We studied pressure-induced changes in the crystal structure of high-pressure α-K<sub>2</sub>Ca<sub>3</sub>(CO<sub>3</sub>)<sub>4</sub> phase up to 20 GPa using synchrotron single-crystal x-ray diffraction in diamond anvil cell. At ~ 7 GPa at room temperature the orthorhombic <i>P</i>2<sub>1</sub>2<sub>1</sub>2<sub>1</sub> phase of α-K<sub>2</sub>Ca<sub>3</sub>(CO<sub>3</sub>)<sub>4</sub> undergoes displacive phase transition into monoclinic <i>P</i>112<sub>1</sub> phase. Despite the phase transition, <i>PV</i>-curve does not demonstrate any irregularities so that both phases can be described by the same 4th order Birch-Murnaghan equation of state with <i>V</i><sub>0</sub> = 1072.5(3) Å<sup>3</sup>, <i>K</i><sub>0</sub> = 51.1(8) GPa, <i>K</i>’<sub>0</sub>=3.7(3), <i>K</i>’’<sub>0</sub>=0.12(6).</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
New insight into the phase transition and kinetics of the dehydroxylation of bulk-to-nano chrysotile 大块温石棉到纳米温石棉脱羟基的相变和动力学新见解
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-07-23 DOI: 10.1007/s00269-024-01288-3
Jifa Long, Wentao Liu, Ningbo Zhang, Hanting Zhang, Qi Xiao, Suping Huang
{"title":"New insight into the phase transition and kinetics of the dehydroxylation of bulk-to-nano chrysotile","authors":"Jifa Long,&nbsp;Wentao Liu,&nbsp;Ningbo Zhang,&nbsp;Hanting Zhang,&nbsp;Qi Xiao,&nbsp;Suping Huang","doi":"10.1007/s00269-024-01288-3","DOIUrl":"10.1007/s00269-024-01288-3","url":null,"abstract":"<div><p>In this work, the self-made chrysotile fiber membrane (CFM) and raw chrysotile fiber (CF) were calcined in air from 500 to 800 °C. The XRD pattern of CFM showed that the diffraction peak of chrysotile weakened when the temperature was from room temperature to 550 °C, and CFM had a shorter amorphous interval at 600–700 °C. While, no amorphous phase appeared in CF during calcination, and forsterite begined to appear at 650 °C. SEM images showed that CFM could still maintain the integrity of the network structure at 600–800 °C, while CF gradually melted into coarse fiber bundles with the increase of calcination temperature, and sintering traces appeared. After that,the kinetics of the dehydroxylation of chrysotile in CFM and CF was studied. The dehydroxylation of CFM is a one-step reaction, the calculated activation energy is 243.33 kJ mol<sup>−1</sup>, which conforms to the two-dimensional ‘Valensi’ model with mechanism function G(α) = (1−α)ln(1−α) + α. The dehydroxylation of CF is divided into two stages, the activation energy are 222.87 kJ mol<sup>−1</sup> and 316.04 kJ mol<sup>−1</sup>. The first stage of CF conforms to two-dimensional ‘Jander’ model (n = 2) with mechanism function G(α) = [1−(1−α)<sup>1/2</sup>]<sup>2</sup>, the second stage of CF conforms to the random nucleation and subsequent growth ‘Avrami-Erofeev’ model (n = 3/2) with mechanism function G(α) = [−ln(1−α)]<sup>2/3</sup><i>.</i></p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141783927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Theoretical infrared signature of OH defects in Fe3+, Cr3+ and Al3+-doped enstatite 掺杂 Fe3+、Cr3+ 和 Al3+ 的芒硝中 OH 缺陷的理论红外特征
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-07-20 DOI: 10.1007/s00269-024-01289-2
Etienne Balan, Jannick Ingrin
{"title":"Theoretical infrared signature of OH defects in Fe3+, Cr3+ and Al3+-doped enstatite","authors":"Etienne Balan,&nbsp;Jannick Ingrin","doi":"10.1007/s00269-024-01289-2","DOIUrl":"10.1007/s00269-024-01289-2","url":null,"abstract":"<div><p>The infrared spectroscopic properties of selected defects involving one proton and one nearby M<sup>3+</sup> (M = Al, Cr, Fe) substitution in orthoenstatite are investigated by first-principles calculations. Based on the theoretical results, the absorption bands experimentally observed on synthetic samples with high crystalline quality and low doping levels can be assigned to specific defect configurations. Most of them correspond to Mg vacancies at M2 sites locally compensated by one proton and one M<sup>3+</sup> cation at a nearby M1 site. This confirms that the M<sup>3+</sup> + H<sup>+</sup> = 2 Mg<sup>2+</sup> exchange mechanism is the dominant hydrogen incorporation mechanism at the lowest concentration levels in doped enstatite. At higher concentration levels, more complex incorporation mechanisms could become dominant in Al-bearing samples.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141739897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Pressure–volume equation of state of Fe18Pt82 Fe18Pt82 的压力-体积状态方程
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-07-20 DOI: 10.1007/s00269-024-01275-8
Meryem Berrada, Siheng Wang, Bin Chen, Vitali Prakapenka, Stella Chariton, Marc M. Hirschmann, Jie Li
{"title":"Pressure–volume equation of state of Fe18Pt82","authors":"Meryem Berrada,&nbsp;Siheng Wang,&nbsp;Bin Chen,&nbsp;Vitali Prakapenka,&nbsp;Stella Chariton,&nbsp;Marc M. Hirschmann,&nbsp;Jie Li","doi":"10.1007/s00269-024-01275-8","DOIUrl":"10.1007/s00269-024-01275-8","url":null,"abstract":"<div><p>Platinum-iron (Pt-Fe) alloys have long served as oxygen fugacity sensors in high-temperature experiments investigating Earth and planetary interiors, relying on the equilibrium between Fe within the alloy and FeO in coexisting oxides or silicates. Despite their significance, studies on intermediate compositions remain limited. This investigation focuses on compressibility of Fe<sub>18</sub>Pt<sub>82</sub> up to <span>(sim)</span> 40 GPa at ambient temperature and explores the pressure-dependent characteristics of the oxygen fugacity relationship. In-situ X-ray diffraction measurements confirm the stability of the <i>fcc</i> phase in Fe<sub>18</sub>Pt<sub>82</sub> across the pressure range. The fit to the compression data by the third-order Birch–Murnaghan equation of state results in <span>({V}_{0}=59.14 pm 0.08)</span>Å<sup>3</sup>, <span>({K}_{0}=266 pm 13)</span> GPa, and <span>({K}_{0}^{prime}=4.7 pm 0.7)</span>. The differences between this fit and the Vinet and Kunc equations of state fall within the range of uncertainty. Comparing results with reported data for other Pt-Fe alloys reveals a nearly linear trend between volume and the Fe content in Pt-Fe alloys at ambient pressure. Unlike more iron-rich alloys, the excess volume of mixing of Fe<sub>18</sub>Pt<sub>82</sub> (<span>(sim)</span> 0.21 cm<sup>3</sup>/mol) remains nearly constant across the examined pressure range. Estimates of the excess Gibbs free energy suggest diminishing non-ideal contributions to thermodynamic activities as pressure increases.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":"51 3","pages":""},"PeriodicalIF":1.2,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141739898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Purification mechanism of microcrystalline graphite and dissolution of non-carbon impurity during alkali autoclave-acid leaching 碱高压釜-酸浸出过程中微晶石墨的净化机理和非碳杂质的溶解
IF 1.2 4区 地球科学
Physics and Chemistry of Minerals Pub Date : 2024-07-18 DOI: 10.1007/s00269-024-01290-9
Zhang Xiyue, Sun Hongjuan, Peng Tongjiang, Zeng Li, Liu Bo
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