Ultrahigh purity CaCO3 whiskers derived from the enhanced diffusion of carbonate ions from a larger liquid–gas interface through porous quartz stones

CrystEngComm ◽  
2020 ◽  
Vol 22 (38) ◽  
pp. 6407-6414
Author(s):  
Qinglei Li ◽  
Zhengguan Dai ◽  
Dengkui Shang ◽  
Chong Yin ◽  
Piyi Du ◽  
...  
Keyword(s):  
High Purity ◽  
Interface Area ◽  
Enhanced Diffusion ◽  
Carbonation Process ◽  
Carbonate Ions ◽  
Porous Quartz

A larger liquid–gas interface area during the carbonation process for preparing high-purity aragonite CaCO3 whiskers by using porous quartz stones was developed.

scholarly journals Effect of Methane on the Synthesis of Precipitated Calcium Carbonate via Carbonation Process

2019 ◽  
Vol 7 (4.14) ◽  
pp. 163
Author(s):  
H M. Lahuri ◽  
N H. Berahim ◽  
M S. Onn ◽  
M G.M. Noh ◽  
R Othman
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
High Purity ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Ambient Conditions ◽  
Mixing Rate ◽  
Precipitated Calcium Carbonate ◽  
X Ray ◽  
Carbonation Process

Precipitated calcium carbonate (PCC) is synthetic calcium carbonate that has high purity of more than 98 wt% of CaCO3 content.  Owing to its unique characteristic whereby its shape and size can be controlled to tailor to various applications, PCC has seen great demands in many industries such as paper, paint, plastic, food, ceramics, cosmetics, pharmaceutical, and many others.  PCC can be synthesized via various methods and the most often used method in industry is via carbonation process.  This process has caught interest of the oil and gas industry for utilizing existing carbon dioxide waste from plant processes.  Precipitation of PCC is carried out using hydrated lime under various conditions at different gas purity (1 mol% CH4 + 99 mol% CO2 , 40 mol% CH4  + 60 mol% CO2 ), different gas flowrate, and different stirring rate.  All experiments are carried out using 1 litre of ionic solution at ambient conditions.  All samples are characterized using Field Emission Scanning Electron Microscopy (FESEM), Particle Size Distribution, X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF).  FESEM analysis shows different surface morphology for different methane content with calcite formation.  The particle size for all PCC produced at different parameters are comparable at the range 5-9 microns depending on the mixing rate used whereas XRF results indicate very high purity of CaCO3 of more than 99 wt%. 

scholarly journals Effect of Methane on the Synthesis of Precipitated Calcium Carbonate via Carbonation Process

2019 ◽  
Vol 7 (4.14) ◽  
pp. 163
Author(s):  
H M. Lahuri ◽  
N H. Berahim ◽  
M S. Onn ◽  
M G.M. Noh ◽  
R Othman
Keyword(s):  
Particle Size ◽  
Calcium Carbonate ◽  
High Purity ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Ambient Conditions ◽  
Mixing Rate ◽  
Precipitated Calcium Carbonate ◽  
X Ray ◽  
Carbonation Process

Precipitated calcium carbonate (PCC) is synthetic calcium carbonate that has high purity of more than 98 wt% of CaCO3 content.  Owing to its unique characteristic whereby its shape and size can be controlled to tailor to various applications, PCC has seen great demands in many industries such as paper, paint, plastic, food, ceramics, cosmetics, pharmaceutical, and many others.  PCC can be synthesized via various methods and the most often used method in industry is via carbonation process.  This process has caught interest of the oil and gas industry for utilizing existing carbon dioxide waste from plant processes.  Precipitation of PCC is carried out using hydrated lime under various conditions at different gas purity (1 mol% CH4 + 99 mol% CO2 , 40 mol% CH4  + 60 mol% CO2 ), different gas flowrate, and different stirring rate.  All experiments are carried out using 1 litre of ionic solution at ambient conditions.  All samples are characterized using Field Emission Scanning Electron Microscopy (FESEM), Particle Size Distribution, X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF).  FESEM analysis shows different surface morphology for different methane content with calcite formation.  The particle size for all PCC produced at different parameters are comparable at the range 5-9 microns depending on the mixing rate used whereas XRF results indicate very high purity of CaCO3 of more than 99 wt%. 

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

High-purity Ge x-ray detectors: Sensitivity factors and usefulness

1990 ◽  
Vol 48 (2) ◽  
pp. 548-548
Author(s):  
E. B. Steel
Keyword(s):  
High Purity ◽  
High Energy ◽  
Quantitative Chemical Analysis ◽  
Detector Performance ◽  
X Ray ◽  
Detector Sensitivity ◽  
Specimen Holder ◽  
Many Instruments ◽  
Charge Resolution ◽  
Sensitivity Factors

High Purity Germanium (HPGe) x-ray detectors are now commercially available for the analytical electron microscope (AEM). The detectors have superior efficiency at high x-ray energies and superior resolution compared to traditional lithium-drifted silicon [Si(Li)] detectors. However, just as for the Si(Li), the use of the HPGe detectors requires the determination of sensitivity factors for the quantitative chemical analysis of specimens in the AEM. Detector performance, including incomplete charge, resolution, and durability has been compared to a first generation detector. Sensitivity factors for many elements with atomic numbers 10 through 92 have been determined at 100, 200, and 300 keV. This data is compared to Si(Li) detector sensitivity factors.The overall sensitivity and utility of high energy K-lines are reviewed and discussed. Many instruments have one or more high energy K-line backgrounds that will affect specific analytes. One detector-instrument-specimen holder combination had a consistent Pb K-line background while another had a W K-line background.

Ion Beam Mixing of Ni-Ti Bilayered Thin Films

1985 ◽  
Vol 43 ◽  
pp. 290-291
Author(s):  
A. K. Rai ◽  
R. S. Bhattacharya ◽  
M. H. Rashid
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Amorphous Alloys ◽  
Ion Beam ◽  
Ion Bombardment ◽  
High Energy ◽  
Mixing Efficiency ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Binary Metal

Ion beam mixing has recently been found to be an effective method of producing amorphous alloys in the binary metal systems where the two original constituent metals are of different crystal structure. The mechanism of ion beam mixing are not well understood yet. Several mechanisms have been proposed to account for the observed mixing phenomena. The first mechanism is enhanced diffusion due to defects created by the incoming ions. Second is the cascade mixing mechanism for which the kinematicel collisional models exist in the literature. Third mechanism is thermal spikes. In the present work we have studied the mixing efficiency and ion beam induced amorphisation of Ni-Ti system under high energy ion bombardment and the results are compared with collisional models. We have employed plan and x-sectional veiw TEM and RBS techniques in the present work.

TEM characterization of WSix films

1994 ◽  
Vol 52 ◽  
pp. 848-849
Author(s):  
V. C. Kannan ◽  
S. M. Merchant ◽  
R. B. Irwin ◽  
A. K. Nanda ◽  
M. Sundahl ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Vapor Deposition ◽  
High Purity ◽  
Physical Vapor Deposition ◽  
Thermal Treatments ◽  
Rapid Thermal Anneal ◽  
Tungsten Silicide ◽  
Tem Characterization ◽  
Metal Silicides

Metal silicides such as WSi2, MoSi2, TiSi2, TaSi2 and CoSi2 have received wide attention in recent years for semiconductor applications in integrated circuits. In this study, we describe the microstructures of WSix films deposited on SiO2 (oxide) and polysilicon (poly) surfaces on Si wafers afterdeposition and rapid thermal anneal (RTA) at several temperatures. The stoichiometry of WSix films was confirmed by Rutherford Backscattering Spectroscopy (RBS). A correlation between the observed microstructure and measured sheet resistance of the films was also obtained.WSix films were deposited by physical vapor deposition (PVD) using magnetron sputteringin a Varian 3180. A high purity tungsten silicide target with a Si:W ratio of 2.85 was used. Films deposited on oxide or poly substrates gave rise to a Si:W ratio of 2.65 as observed by RBS. To simulatethe thermal treatments of subsequent processing procedures, wafers with tungsten silicide films were subjected to RTA (AG Associates Heatpulse 4108) in a N2 ambient for 60 seconds at temperatures ranging from 700° to 1000°C.

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