scholarly journals In situ Observations of the Crystallization of Beryl and Phenakite in Aqueous Solutions in a Hydrothermal Diamond-Anvil Cell

2020 ◽  
Author(s):  
Jiankang Li ◽  
Xian Wang ◽  
I-Ming Chou
Keyword(s):  
Aqueous Solutions ◽  
Diamond Anvil Cell ◽  
Diamond Anvil ◽  
In Situ Observations

scholarly journals Homogenization Experiments of Crystal-Rich Inclusions in Spodumene from Jiajika Lithium Deposit, China, under Elevated External Pressures in a Hydrothermal Diamond-Anvil Cell

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Jiankang Li ◽  
I-Ming Chou
Keyword(s):  
Diamond Anvil Cell ◽  
Aqueous Fluid ◽  
Formation Mechanisms ◽  
External Pressures ◽  
Sample Chamber ◽  
New Type ◽  
Diamond Anvil ◽  
In Situ Observations ◽  
Total Dissolution

Extensive studies of the crystal-rich inclusions (CIs) hosted in minerals in pegmatite have resulted in substantially different models for the formation mechanism of the pegmatite. In order to evaluate these previously proposed formation mechanisms, the total homogenization processes of CIs hosted in spodumene from the Jiajika pegmatite deposit in Sichuan, China, were observed in situ under external H2O pressures in a new type of hydrothermal diamond-anvil cell (HDAC). The CIs in a spodumene chip were loaded in the sample chamber of HDAC with water, such that the CIs were under preset external H2O pressures during heating to avoid possible decrepitation. Our in situ observations showed that the crystals within the CIs were dissolved in carbonic-rich aqueous fluid during heating and that cristobalite was usually the first mineral being dissolved, followed by zabuyelite and silicate minerals until their total dissolution at temperatures between 500 and 720°C. These observations indicated that the minerals within the CIs were daughter minerals crystallized from an entrapped carbonate- and silica-rich aqueous solution and therefore provided useful information for evaluating the formation models of granitic pegmatites.

scholarly journals The Solubility of Tugarinovite (MoO2) in H2O at Elevated Temperatures and Pressures

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Pritam Saha ◽  
Alan J. Anderson ◽  
Thomas Lee ◽  
Matthias Klemm
Keyword(s):  
Aqueous Solutions ◽  
Diamond Anvil Cell ◽  
Elevated Temperatures ◽  
Pure Water ◽  
Bearing Steel ◽  
Steel Alloys ◽  
X Ray ◽  
Diamond Anvil ◽  
Increasing Temperature

The solubility of tugarinovite (MoO2) in pure water was investigated at temperatures between 400 and 800°C and at pressures ranging between 95 and 480 MPa by using in situ synchrotron X-ray fluorescence (SXRF) to separately analyze high temperature aqueous solutions in a hydrothermal diamond anvil cell (HDAC). The concentration of molybdenum in the fluid at 400 and 500°C was below detection; however, at temperatures between 600 and 800°C, the solubility of tugarinovite increased with increasing temperature by two orders of magnitude. The molybdenum concentration at 600°C and 800°C is 44 ppm and 658 ppm, respectively. The results complement the data of Kudrin (1985) and provide the first measurement of MoO2 solubility at pressure and temperature conditions comparable to intrusion-related Mo deposit formation. The data are also relevant to the study of water chemistry and corrosion product transport in supercritical-water-cooled reactors, where Mo-bearing steel alloys interact with aqueous solutions at temperatures greater than 600°C. The application of in situ SXRF to solubility measurements of sparingly soluble minerals is recommended because it circumvents analytical uncertainties inherent in determinations obtained by quenching and weight loss measurements.

PHASE TRANSITION IN LAYERED PEROVSKITE LIKE MANGANATE Ca3Mn2O7 UNDER HIGH PRESSURE

2001 ◽  
Vol 15 (18) ◽  
pp. 2491-2497 ◽  
Author(s):  
J. L. ZHU ◽  
L. C. CHEN ◽  
R. C. YU ◽  
F. Y. LI ◽  
J. LIU ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
The Other ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Diamond Anvil

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.

Construction of laser-heated diamond anvil cell system for in situ x-ray diffraction study at SPring-8

2001 ◽  
Vol 72 (2) ◽  
pp. 1289 ◽  
Author(s):  
Tetsu Watanuki ◽  
Osamu Shimomura ◽  
Takehiko Yagi ◽  
Tadashi Kondo ◽  
Maiko Isshiki
Keyword(s):  
Diffraction Study ◽  
Diamond Anvil Cell ◽  
Cell System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Anvil ◽  
Laser Heated

Infrared Microspectroscopy in Earth and Planetary Science: Recent Developments, Including In Situ High-Pressure, High-Temperature Techniques

1997 ◽  
Vol 3 (S2) ◽  
pp. 857-858
Author(s):  
A.M. Hofmeister
Keyword(s):  
Diamond Anvil Cell ◽  
Earth Science ◽  
Interplanetary Dust ◽  
Diffraction Limit ◽  
Planetary Science ◽  
Infrared Microspectroscopy ◽  
High Pressure High Temperature ◽  
Recent Developments ◽  
Diamond Anvil

Vibrational spectroscopy is used in Earth science for both quantitative and qualitative analysis. This report focuses on infrared (IR) spectroscopy, although similar efforts are on-going in Raman spectroscopy.Qualitative studies utilize the fact that the vibrational spectrum is a characteristic of a material: hence comparison to a set of standards allows for identification of the phase. Most of these types of studies in Earth science involve macrosamples, but measurements of microsamples from meteorites are on interest in order to identify the structure of SiC inclusions and the type of organic compounds in interplanetary dust. As most of these samples are micron sized, which is below the diffraction limit for the mid-IR, the approach has been to compress the sample using a diamond anvil cell (DAC) into a disk of sub-micron thickness, adhere the sample to a KBr plate, and to subsequently remove the disk from the DAC and obtain spectra with the aid of an FTIR microscope.

scholarly journals Reliability of multigrain indexing for orthorhombic polycrystals above 1 Mbar: application to MgSiO3 post-perovskite

2017 ◽  
Vol 50 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Christopher Langrand ◽  
Nadège Hilairet ◽  
Carole Nisr ◽  
Mathieu Roskosz ◽  
Gábor Ribárik ◽  
...  
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Grain Orientation ◽  
Diamond Anvil Cell ◽  
Polycrystalline Material ◽  
Data Set ◽  
Grain Orientations ◽  
Diamond Anvil ◽  
Diffraction Peaks

This paper describes a methodology for characterizing the orientation and position of grains of an orthorhombic polycrystalline material at high pressure in a diamond anvil cell. The applicability and resolution of the method are validated by simulations and tested on an experimental data set collected on MgSiO3 post-perovskite at 135 GPa. In the simulations, ∼95% of the grains can be indexed successfully with ∼80% of the peaks assigned. The best theoretical average resolutions in grain orientation and position are 0.02° and 1.4 µm, respectively. The indexing of experimental data leads to 159 grains of post-perovskite with 30% of the diffraction peaks assigned with a 0.2–0.4° resolution in grain orientation. The resolution in grain location is not sufficient for in situ analysis of spatial relationships at high pressure. The grain orientations are well resolved and sufficient for following processes such as plastic deformation or phase transformation. The paper also explores the effect of the indexing parameters and of experimental constraints such as rotation range and step on the validity of the results, setting a basis for optimized experiments.

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