scholarly journals Incorporation of Incompatible Strontium and Barium Ions into Calcite (CaCO3) through Amorphous Calcium Carbonate

Minerals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 270 ◽  
Author(s):  
Ayaka Saito ◽  
Hiroyuki Kagi ◽  
Shiho Marugata ◽  
Kazuki Komatsu ◽  
Daisuke Enomoto ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Room Temperature ◽  
Barium Carbonate ◽  
X Ray Diffraction ◽  
Amorphous Calcium Carbonate ◽  
Static Disorder ◽  
Ionic Radii ◽  
Barium Ions ◽  
Alkaline Earth Elements ◽  
Xrd Patterns

Calcite is a ubiquitous mineral in nature. Heavy alkaline-earth elements with large ionic radii such as Sr2+ and Ba2+ are highly incompatible to calcite. Our previous study clarified that incompatible Sr2+ ions can be structurally incorporated into calcite through crystallization from amorphous calcium carbonate (ACC). In this study, we synthesized Sr-doped calcite with Sr/(Sr + Ca) up to 30.7 ± 0.6 mol% and Ba-doped calcite with Ba/(Ba + Ca) up to 68.6 ± 1.8 mol%. The obtained Ba-doped calcite samples with Ba concentration higher than Ca can be interpreted as Ca-containing barium carbonates with the calcite structure which have not existed so far because barium carbonate takes the aragonite structure. X-ray diffraction (XRD) patterns of the Sr-doped and Ba-doped calcite samples obtained at room temperature showed that reflection 113 gradually weakened with increasing Sr/(Sr + Ca) or Ba/(Ba + Ca) ratios. The reflection 113 disappeared at Ba/(Ba + Ca) higher than 26.8 ± 1.6 mol%. Extinction of reflection 113 was reported for pure calcite at temperatures higher than 1240 K, which was attributed to the rotational (dynamic) disorder of CO32− in calcite. Our Molecular Dynamics (MD) simulation on Ba-doped calcite clarified that the CO32− ions in Ba-doped calcites are in the static disorder at room temperature. The CO32− ions are notable tilted and displaced from the equilibrium position of pure calcite.

STUDY OF THE INFLUENCE BETWEEN BARIUM IONS AND CALCIUM IONS ON MORPHOLOGY AND SIZE OF COPRECIPITATION IN MICROEMULSION

2015 ◽  
Vol 22 (03) ◽  
pp. 1550036 ◽  
Author(s):  
NONG WANG ◽  
QING LUO MENG
Keyword(s):  
Calcium Carbonate ◽  
Barium Carbonate ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Barium Ions ◽  
Molar Ratios ◽  
Measurement Results ◽  
Inverse Microemulsion ◽  
Barium Ion ◽  
System Phase

In this paper, we systematically drew a series of inverse-microemulsion quasi-ternary system phase diagrams of OP -10+ C 8 H 17 OH + C 6 H 12+ brine  ( CaCl 2/ BaCl 2) by adjusting the ratio of CaCl 2 and BaCl 2. On this basis, microemulsions have been prepared with seven different molar ratios of Ca 2+/ Ba 2+, and calcium carbonate and barium carbonate coprecipitation products were obtained by reaction with an equimolar amount of sodium carbonate. The influence of barium ion to morphology and composition of nanometer calcium carbonate were studied. These samples were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The SEM photographs indicated that when the content of Ca 2+ was higher, some incomplete large cube of coprecipitation particles were formed in solution, but with the content of Ba 2+ increased gradually, they formed a large number of small spherical particles, with the further increase of Ba 2+ concentration, the particles mainly had structures of irregular polyhedron eventually. The measurement results of FTIR and XRD indicated that CaCO 3 coprecipitation products gradually changed from calcite to the vaterite, eventually turned into being aragonite with the further increase of Ba 2+ concentration.

scholarly journals Pure hydroxyapatite synthesis originating from amorphous calcium carbonate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michika Sawada ◽  
Kandi Sridhar ◽  
Yasuharu Kanda ◽  
Shinya Yamanaka
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Room Temperature ◽  
Molar Ratio ◽  
Final Phase ◽  
Amorphous Calcium Carbonate ◽  
Phosphate Compound ◽  
Synthesis Strategy ◽  
Phosphorylation Reaction ◽  
Subsequent Calcination

AbstractWe report a synthesis strategy for pure hydroxyapatite (HAp) using an amorphous calcium carbonate (ACC) colloid as the starting source. Room-temperature phosphorylation and subsequent calcination produce pure HAp via intermediate amorphous calcium phosphate (ACP). The pre-calcined sample undergoes a competitive transformation from ACC to ACP and crystalline calcium carbonate. The water content, ACC concentration, Ca/P molar ratio, and pH during the phosphorylation reaction play crucial roles in the final phase of the crystalline phosphate compound. Pure HAp is formed after ACP is transformed from ACC at a low concentration (1 wt%) of ACC colloid (1.71 < Ca/P < 1.88), whereas Ca/P = 1.51 leads to pure β-tricalcium phosphate. The ACP phases are precursors for calcium phosphate compounds and may determine the final crystalline phase.

STRUCTURE AND MAGNETIC PROPERTIES OF MECHANICAL ALLOYED Mn-15at.%Al

2013 ◽  
Vol 12 (01) ◽  
pp. 1350006
Author(s):  
AHMED E. HANNORA ◽  
FARIED F. HANNA ◽  
LOTFY K. MAREI
Keyword(s):  
Thermal Analysis ◽  
Room Temperature ◽  
Average Crystallite Size ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Milled Sample ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Method Analysis

Mechanical alloying (MA) method has been used to produce nanocrystallite Mn -15at.% Al alloy. X-ray diffraction (XRD) patterns for the as-milled elemental α- Mn and aluminum powder samples show a mixture of α + β- MnAl phases after 20 h of milling and changes to a dominant β- MnAl phase structure after 50 h. An average crystallite size of 40 nm was determined from Hall–Williamson method analysis after 5 h of milling. Moreover, the thermal analysis results using differential thermal analysis (DTA), suggested a possible phase transformation after 20 h of milling. Isothermal treatments are carried in the temperature range of 450°C to 1000°C. Room-temperature vibrating sample magnetometer (VSM) measurements of the hysteretic response revealed that the saturation magnetization Bs and coercivity Hc for 10 h ball milled sample are ~ 2.1 emu/g and ~ 92 Oe, respectively.

An X-ray diffraction system with controlled relative humidity and temperature

1996 ◽  
Vol 11 (4) ◽  
pp. 288-289 ◽  
Author(s):  
H. Hashizume ◽  
S. Shimomura ◽  
H. Yamada ◽  
T. Fujita ◽  
H. Nakazawa ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Room Temperature ◽  
Control Unit ◽  
Saturated Water Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Saturated Water ◽  
Sample Chamber ◽  
Diffraction Patterns ◽  
Xrd Patterns

A system enabling X-ray diffraction patterns under controlled conditions of relative humidity and temperature has been devised and combined with an X-ray powder diffractometer. Relative humidity in the sample space is controlled by mixing dry N2 gas with saturated water vapor. Temperatures of the sample and inner wall of the sample chamber are monitored by two attached thermocouples and the information was fed back to the control unit. Relative humidity between 0% and the 95%, and temperature between room temperature and 60 °C can be controlled. All parameters including those for XRD are programmable and the system runs automatically. The function of the system was checked by recording the XRD patterns of montmorillonite (a clay mineral) and NaCl under increasing and decreasing relative humidity.

scholarly journals Structural, magnetic and electrical properties of a new double-perovskite LaNaMnMoO 6 material

2017 ◽  
Vol 4 (11) ◽  
pp. 170920 ◽  
Author(s):  
Sameh Megdiche Borchani ◽  
Wissem Cheikh-Rouhou Koubaa ◽  
Makrem Megdiche
Keyword(s):  
Applied Field ◽  
Room Temperature ◽  
Double Perovskite ◽  
Entropy Change ◽  
Cooling Power ◽  
Room Temperature Resistivity ◽  
Ferromagnetic Transition ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Xrd Patterns

Structural, magnetic, magnetocaloric, electrical and magnetoresistance properties of an LaNaMnMoO 6 powder sample have been investigated by X-ray diffraction (XRD), magnetic and electrical measurements. Our sample has been synthesized using the ceramic method. Rietveld refinements of the XRD patterns show that our sample is single phase and it crystallizes in the orthorhombic structure with Pnma space group. Magnetization versus temperature in a magnetic applied field of 0.05 T shows that our sample exhibits a paramagnetic–ferromagnetic transition with decreasing temperature. The Curie temperature T C is found to be 320 K. Arrott plots show that all our double-perovskite oxides exhibit a second-order magnetic phase transition. From the measured magnetization data of an LaNaMnMoO 6 sample as a function of the magnetic applied field, the associated magnetic entropy change |−ΔSM| and the relative cooling power (RCP) have been determined. In the vicinity of T C , |−ΔSM| reached, in a magnetic applied field of 8 T, a maximum value of ∼4 J kg −1  K −1 . Our sample undergoes a large magnetocaloric effect at near-room temperature. Resistivity measurements reveal the presence of an insulating-metal transition at Tρ = 180 K. A magnetoresistance of 30% has been observed at room temperature for 6 T, significantly larger than that reported for the A 2 FeMoO 6 (A = Sr, Ba) double-perovskite system.

scholarly journals XRD and TG-DTA Study of New Phosphate-Based Geopolymers with Coal Ash or Metakaolin as Aluminosilicate Source and Mine Tailings Addition

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 202
Author(s):  
Dumitru Doru Burduhos Nergis ◽  
Petrica Vizureanu ◽  
Andrei Victor Sandu ◽  
Diana Petronela Burduhos Nergis ◽  
Costica Bejinariu
Keyword(s):  
Mine Tailings ◽  
Room Temperature ◽  
Raw Materials ◽  
Coal Ash ◽  
Water Evaporation ◽  
Oxidation Reactions ◽  
X Ray Diffraction ◽  
Xrd Patterns ◽  
First Time ◽  
Alkali Activated

Coal ash-based geopolymers with mine tailings addition activated with phosphate acid were synthesized for the first time at room temperature. In addition, three types of aluminosilicate sources were used as single raw materials or in a 1/1 wt. ratio to obtain five types of geopolymers activated with H3PO4. The thermal behaviour of the obtained geopolymers was studied between room temperature and 600 °C by Thermogravimetry-Differential Thermal Analysis (TG-DTA) and the phase composition after 28 days of curing at room temperature was analysed by X-ray diffraction (XRD). During heating, the acid-activated geopolymers exhibited similar behaviour to alkali-activated geopolymers. All of the samples showed endothermic peaks up to 300 °C due to water evaporation, while the samples with mine tailings showed two significant exothermic peaks above 400 °C due to oxidation reactions. The phase analysis confirmed the dissolution of the aluminosilicate sources in the presence of H3PO4 by significant changes in the XRD patterns of the raw materials and by the broadening of the peaks because of typically amorphous silicophosphate (Si–P), aluminophosphate (Al–P) or silico-alumino-phosphate (Si–Al–P) formation. The phases resulted from geopolymerisation are berlinite (AlPO4), brushite (CaHPO4∙2H2O), anhydrite (CaSO4) or ettringite as AFt and AFm phases.

Controlling nucleation in giant liposomes

2014 ◽  
Vol 50 (42) ◽  
pp. 5619-5622 ◽  
Author(s):  
Chantel C. Tester ◽  
Michael L. Whittaker ◽  
Derk Joester
Keyword(s):  
Calcium Carbonate ◽  
Barium Carbonate ◽  
Strontium Carbonate ◽  
Confinement Effects ◽  
Amorphous Calcium Carbonate

Confinement effects in giant liposomes lead to dramatic stabilization of amorphous calcium carbonate (ACC), intermediate stabilization of amorphous strontium carbonate (ASC), but has no effect on the precipitation of barium carbonate.

Solvothermal Synthesis and Magnetic Properties of Fe3O4 Microspheres

2011 ◽  
Vol 393-395 ◽  
pp. 947-950
Author(s):  
De Hui Sun ◽  
Ji Lin Zhang ◽  
De Xin Sun
Keyword(s):  
Room Temperature ◽  
Size Range ◽  
Solvothermal Method ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Magnetic Investigation ◽  
Xrd Patterns ◽  
Fe3o4 Microspheres ◽  
Ftir Absorption Spectra

We synthesized Fe3O4 microspheres using a solvothermal method and characterized their morphologies, structures, surface property and magnetism by field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD) patterns, Fourier transform infrared (FTIR) absorption spectra, and vibrating sample magnetometer (VSM). The results showed that the synthesized Fe3O4 microspheres with a tunable size range of ca. 80–200 nm are composed of many Fe3O4 collective nanoparticles. XRD pattern confirmed that the Fe3O4 microspheres belong to cubic structure. Magnetic investigation reveals that the Fe3O4 microspheres have higher saturation magnetization and negligible coercivity at room temperature.

Influence of Inorganic Ion on the Synthesis of Hollow Calcium Carbonate

2006 ◽  
Vol 11-12 ◽  
pp. 677-680 ◽  
Author(s):  
Gunawan Hadiko ◽  
Yong Sheng Han ◽  
Masayoshi Fuji ◽  
Minoru Takahashi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Room Temperature ◽  
Hollow Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inorganic Ion ◽  
Potential Component ◽  
Scanning Electron

Hollow calcium carbonate (CaCO3) particles were synthesized by bubbling CO2 in the solution of calcium chloride (CaCl2) with the presence of ammonia at room temperature. Hollow calcium carbonate is a potential component to be used as pharmaceuticals, agrochemicals, and catalysis. This paper investigated the effect of additive on the hollow structure. In this study was used vanadate ion as additive agent. Physical characteristics of precipitate were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD).

Synthesis of La10Si6-2xBi2xO27-x as Possible Electrolyte Materials for Solid Oxide Fuel Cells

2017 ◽  
Vol 889 ◽  
pp. 173-177
Author(s):  
Hidayatul Qayyimah Hj Hairul Absah ◽  
Afizul Hakem Karim ◽  
Muhammad Saifullah Abu Bakar ◽  
Lim Chee Ming ◽  
Abul Kalam Azad
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Room Temperature ◽  
Solid State Reaction Method ◽  
Oxide Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heating And Cooling ◽  
Secondary Compound ◽  
Xrd Patterns ◽  
Primary Compound

La10Si6-2xBi2xO27-x (x = 0.22, 0.46 and 0.72) ceramics have been synthesized by the solid-state reaction method. The calcination temperature of La10Si6-2xBi2xO27-x was 900°C for 4 hours and the sintering temperature was 1500°C for 5 hours with the heating and cooling rates of 10°C per minute. Crystal structures of La10Si6-2xBi2xO27-x have been characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Room temperature XRD patterns of La10Si6-2xBi2xO27-x ceramics doped with Bi3+ show hexagonal apatite structure with space group P63/m as the primary compound with minor appearance of La2SiO5 impurity as the secondary compound. As the bismuth oxide content increased the La2SiO5 impurity also increased. La10Si5.56Bi0.44O26.78 has the highest bulk density of 5.2 gcm-3 and good microstructure compared to La10Si5.08Bi0.92O26.54 and La10Si4.56Bi1.44O26.28.

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