scholarly journals Thermal Annealing and Phase Transformation of Serpentine-like Garnierite

2021 ◽  
Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Thermal Annealing ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Microraman Spectroscopy

This study deals with vibrational and crystallographic aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite have been annealed in static air between room temperature and 1000 °C. The resulting products from the transformations detected based on thermogravimetric and differential thermal analysis, have been extensively characterized via microRaman spectroscopy, and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.

scholarly journals Thermal Annealing and Phase Transformation of Serpentine-Like Garnierite

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 188
Author(s):  
Arun Kumar ◽  
Michele Cassetta ◽  
Marco Giarola ◽  
Marco Zanatta ◽  
Monique Le Guen ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Raman Spectroscopy ◽  
Phase Transformation ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Thermally Induced ◽  
X Ray ◽  
Micro Raman Spectroscopy

This study is focused on the vibrational and microstructural aspects of the thermally induced transformation of serpentine-like garnierite into quartz, forsterite, and enstatite occurring at about 620 °C. Powder specimens of garnierite were annealed in static air between room temperature and 1000 °C. The kinetic of the transformation was investigated by means of thermogravimetric and differential thermal analysis, and the final product was extensively characterized via micro-Raman spectroscopy and X-ray diffraction. Our study shows that serpentine-like garnierite consists of a mixture of different mineral species. Furthermore, these garnierites and their composition can provide details based on the mineralogy and the crystalline phases resulting from the thermal treatment.

Study on Character of Ilmenite Modified by Thermal Treatment

2011 ◽  
Vol 284-286 ◽  
pp. 2090-2093 ◽  
Author(s):  
Xue Liang Xiong ◽  
Zhi Yang ◽  
Hong Yong Ouyang
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Oxidation Temperature ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray

The character of ilmenite was modified by pretreatment, the effect of pre-oxidation temperature and time on structure of ilmenite were investigated by X-ray diffraction(XRD) and Thermo-gravimetric/differential thermal analysis. The results indicated that new microcrystal rutile and FeTiO3·Fe2O3 solid solution were appeared on the surface of mineral below 800°C, but evident rutile crystals and pseudobrookite Fe2O3·TiO2 were appeared above 850°C with the structure of ilmenite disrupting simultaneously. The preoxidation time increased from 15min to 60min, evident microcrystal rutile and FeTiO3·Fe2O3 solid solution were appeared by degrees without structure of ilmenite breaking.

Structural, kinetic and thermodynamic aspects of the conformational dimorphism of diethyl 3,6-dibromo-2,5-dihydroxyterephthalate

1996 ◽  
Vol 52 (4) ◽  
pp. 697-706 ◽  
Author(s):  
C. Näther ◽  
N. Nagel ◽  
H. Bock ◽  
W. Seitz ◽  
Z. Havlas
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Room Temperature ◽  
Molecular Conformation ◽  
Local Energy ◽  
X Ray Diffraction ◽  
Ethanolic Solution ◽  
Crystal Forms ◽  
X Ray ◽  
Ethanol Solvate

The crystal structures of the title compound and of its ethanol solvate have been determined by X-ray diffraction. The compound crystallizes in two different crystal forms (I: P21/n, high-temperature stable modification, II: P21/c, room-temperature stable modification), which differ in molecular conformation and hydrogen bonding. Ab initio calculations show that both observed conformations correspond to local energy minima and predict the conformation in polymorph (II) to be energetically more favourable. Packing energy calculations confirm that form (II) should be more stable than form (I). Crystals of both modifications and a solvate, containing 2 equiv, of ethanol, can be obtained by slow crystallization from ethanolic solution. Modification (II) transforms to (I) at 391 K, as shown by optical microscopy, powder diffraction and differential thermal analysis (DTA), whereas (I) melts at 429 K without previous transformation.

GRAFTING INTERLAYER MoO42- IN Mg/Al LAYERED DOUBLE HYDROXIDE BY THERMAL TREATMENT BELOW COLLAPSING THE LAYERED STRUCTURE

2012 ◽  
Vol 06 ◽  
pp. 127-132
Author(s):  
Kennichi Muranishi ◽  
Akihiro Shimamura ◽  
Masashi Kurashina ◽  
Eiji Kanezaki
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermal Treatment ◽  
Layered Double Hydroxide ◽  
Interlayer Spacing ◽  
Basal Spacing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Interlayer Anion ◽  
Double Hydroxide

Some kinds of Mg / Al layered double hydroxide (LDH) with oxometalate have been prepared by mean of anion exchange. Products were characterized by powder X-ray diffraction (XRD), chemical analysis and Thermogravimetry - Differential Thermal Analysis (TG-DTA). Results showed that the basal spacing of heated LDH decreased with heating to 300 °C. This revealed the decrease of interlayer spacing and the interlayer anion being grafted to the layer of LDH because the decreased interlayer spacing of the heated LDH was smaller than the size of the interlayer anion.

A tetranuclear copper (II) complex with pyrazole-3,5-dicarboxylate ligands: synthesis, characterization and electrochemical properties

2016 ◽  
Vol 71 (4) ◽  
pp. 305-310 ◽  
Author(s):  
Selçuk Demir ◽  
Hamide Merve Çepni ◽  
Małgorzata Hołyńska ◽  
Muammer Kavanoz
Keyword(s):  
Crystal Structure ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Magnetic Measurements ◽  
Metal Oxidation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complex Anions

AbstractA tetranuclear copper (II) complex with pyrazole-3,5-dicarboxylate ligands (pdc3−), [Me2NH2]4[Cu4(pdc)4], was synthesized using solvothermal and metal oxidation routes and characterized by elemental analysis, infrared, thermogravimetry/differential thermal analysis, and room-temperature magnetic measurements. The structure of the complex was determined by single-crystal X-ray diffraction. It comprises dimethylammonium cations and complex anions containing four Cu2+ cations. The crystal structure is stabilized by N–H···O hydrogen bonds. In addition, the electrochemical behavior was studied.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

scholarly journals The Potential for Natural Stones from Northeastern Brazil to Be Used in Civil Construction

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 440
Author(s):  
Fabiana Pereira da Costa ◽  
Jucielle Veras Fernandes ◽  
Luiz Ronaldo Lisboa de Melo ◽  
Alisson Mendes Rodrigues ◽  
Romualdo Rodrigues Menezes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Resistance ◽  
Mechanical Analysis ◽  
Northeastern Brazil ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Agents ◽  
Natural Stones

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.

scholarly journals X-Ray Investigations of the Low-Temperature Phases of the Organic Metals α- and β-(BEDT-TTF)2I3

1986 ◽  
Vol 41 (11) ◽  
pp. 1319-1324 ◽  
Author(s):  
H. Endres ◽  
H. J. Keller ◽  
R. Swietlik ◽  
D. Schweitzer ◽  
K. Angermund ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Room Temperature ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
Slight Variation ◽  
X Ray ◽  
Organic Metals ◽  
Β Phase ◽  
Α Phase

The structure of single crystals of the organic metals α- and β-(BEDT-TTF)2I3* was determined at 100 K, well below the phase transitions indicated by resistivity and thermopower measurements as well as by differential thermal analysis. In the α-phase no unusual change of the room temperature unit cell but a slight variation in the triiodide network and especially a more pronounced dimerization in one of the two donor stacks have been found. The β-phase develops a superstructure with a unit cell volume three times as large as that at room temperature and with pronounced distortions of the I3--ions.

The Roman Ceramics of Salobrena (Granada-Spain) and their Raw Materials

1992 ◽  
Vol 267 ◽  
Author(s):  
Ana M De Andres ◽  
Isabel MuÑOZ
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Raw Materials ◽  
Third Century ◽  
Western Coast ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Third ◽  
Good Number ◽  
Scanning Electron

ABSTRACTNineteen roman ceramic sherds found near Salobreña (Granada, Spain), in the western coast of the Mediterranean Sea, as well as different ceramic clays from the surroundingsare studied. Both clays and ceramic sherds are characterizad by X-ray diffraction and spectrometry, differential thermal analysis, and scanning electron and optical microscopies. A good number of the ceramic pieces, among which some “Terrae Sigillatae”, have a composition similar to that of the local clays and, thus, have been probably manufactured at Salobreña. Only a few of them have a foreign origin. For most of them, the firing temperature was about 800-850 °C, although some have been produced at 900-1000 °C, and some others at 1000-1100 °C. It is concluded that Salobreña appearsto have been an important settlement just in the third century of the Christian era.

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.

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