scholarly journals Differential thermal analysis of Kharidhunga magnesite

1991 ◽  
Vol 7 ◽  
Author(s):  
Vishnu Dangol
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Analysis ◽  
The Other ◽  
Sharp Rise ◽  
Magnesite Deposit ◽  
Dta And Tg ◽  
Dta Curves ◽  
Representative Samples

The DTA curves of seven representative samples from the Kharidhunga Magnesite Deposit arc asymmetric and show a sharp rise after attaining the maxima between 670 and 700 oC, which indicates the siliceous nature of the magnesite. The overlapped endothermic peaks al 770 oC and 860 oC characterize the presence of calcite and dolomite respectively as the other impurities. The results of DTA and TG are also compared with the available data of chemical analysis.

Preparation of Glass-Ceramics Using Molybdenum Tailings

2011 ◽  
Vol 284-286 ◽  
pp. 1431-1434 ◽  
Author(s):  
Jin Rui Zhang ◽  
Ru Wang
Keyword(s):  
Heat Treatment ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Crystalline Phase ◽  
Glass Ceramics ◽  
Chemical Properties ◽  
The Other ◽  
Raw Material ◽  
Physical Chemical ◽  
Nucleation Agents

In order to utilization the molybdenum tailings which be deposited in large quantities. Test used it to prepare glass-ceramics as main raw material, TiO2 as nucleation agents and CaO-Al2O3-SiO2 system and wollastonite as the principal crystalline phase. Heat treatment system of glass-ceramics was based on the differential thermal analysis. The crystalline phase, microstructure and characteristics of glass-ceramics were analysis by XRD, SEM and physical, chemical properties test. The result shows that the performance of glass-ceramics was superior to the other types of building decoration stone.

scholarly journals Primary Bud Hardiness of Four Genotypes of Grapes in Arkansas

1991 ◽  
Vol 116 (5) ◽  
pp. 835-837 ◽  
Author(s):  
Timothy F. Bourne ◽  
J.N. Moore ◽  
Milon F. George
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Cold Hardiness ◽  
Training System ◽  
The Other ◽  
Training Systems ◽  
Freeze Damage ◽  
Vitis Spp

Four interspecific grape hybrids (Vitis spp.) developed in Arkansas were evaluated for primary bud hardiness by differential thermal analysis. Buds from two locations were analyzed over 2 years for acclimation, midwinter hardiness, and deacclimation. In addition, effects of two training systems on cold hardiness of buds were evaluated in one location. The buds of the two genotypes with the greatest component of V. vinifera in their ancestry acclimated more slowly than did the other genotypes. Ultimate midwinter bud hardiness was greater in the genotypes possessing less V. vinifera than other parentage. No effect on cold hardiness due to training system was noted. No natural winter freeze damage was observed on any of the genotypes in the period of observation.

Purification of Bentonite Clays from Cubati, PB, Brazil, for Diversified Applications

2014 ◽  
Vol 805 ◽  
pp. 486-491
Author(s):  
J.M.R. Figueirêdo ◽  
Juliana Melo Cartaxo ◽  
I.A. Silva ◽  
C.D. Silva ◽  
Gelmires Araújo Neves ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Analysis ◽  
Laser Diffraction ◽  
The State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Granulometric Analysis ◽  
Bentonite Clays

The State of Paraíba, Brazil, retains about 88.5% of all Brazilian bentonite, and much of this production comes from deposits in the District of Boa Vista, PB. Nevertheless, the deposits are almost depleted. Recently, new deposits were found, which will increases the reserves of the State, in the regions of Cubati and Pedra Lavrada, PB. The objective of this work is to characterize and develop purified clays, through sieving and hydrocycloning techniques, from those recently discovered bentonites for several applications. The characterization of the sample was done through granulometric analysis by laser diffraction, X-ray diffraction, chemical analysis by X-ray fluorescence, and thermogravimetric and differential thermal analysis. The results show that the samples are typical of bentonite clays, and that the purification solely by hydrocyclone presents the best results.

Vacuum Carburization of Nanometer Tungsten Powder with Carbon Black

2007 ◽  
Vol 534-536 ◽  
pp. 165-168 ◽  
Author(s):  
Luo Ji ◽  
Lin Tao ◽  
Zhi Meng Guo ◽  
Cheng Chang Jia
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Surface Area ◽  
Tungsten Powder ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Vacuum Carburization ◽  
Dta Curves

Vacuum carburization of nanometer tungsten powder was investigated in a simple designed apparatus. An X-Y recorder was used to plot differential thermal analysis (DTA) curves to determine the starting temperature of carburization of four samples with different specific surface area. The product was characterized by X-ray Diffraction (XRD) and small angle X-ray scattering (SAXS). The results show that finer tungsten powder has lower starting temperature of carburization. Tungsten powder, the BET surface area of which is 32.97m2/g, was completely carburized to tungsten carbide at 1050°C, even though the starting temperature was 890°C. The particle was found to grow sharply before carburization.

Crystal Growth in Amorphous Binary Alloys of Zr-Ni System

2007 ◽  
Vol 26-28 ◽  
pp. 675-678 ◽  
Author(s):  
Takeshi Fukami ◽  
I. Noda ◽  
M. Asada ◽  
D. Okai ◽  
T. Yamasaki
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Crystal Growth ◽  
Crystallization Process ◽  
Isothermal Annealing ◽  
Binary Alloys ◽  
Isothermal Condition ◽  
Amorphous State ◽  
Dta Curves

A crystallization process in an amorphous state under isothermal condition is examined for binary alloys ZrNi and ZrNi2 by differential thermal analysis (DTA). Time dependence of DTA curves is measured at several constant temperatures just below crystallization temperature. The fraction of crystallized volume in amorphous state and its time evolution during isothermal annealing are measured. These data are analyzed by the Johnson-Mehl–Avrami formula. The Avrami exponent is 2.4±0.1 for ZrNi and 3~4 depending on the set temperature for ZrNi2. The activation energy for crystallization of amorphous ZrNi and ZrNi2 was estimated by plots of lnt1/2 vs. 1/T.

Phase studies on the iron–selenium system

1968 ◽  
Vol 46 (8) ◽  
pp. 1171-1174 ◽  
Author(s):  
J. E. Dutrizac ◽  
M. B. I. Janjua ◽  
J. M. Toguri
Keyword(s):  
Thermal Analysis ◽  
Phase Diagram ◽  
Differential Thermal Analysis ◽  
The Other ◽  
Sampling Techniques ◽  
Liquid Region ◽  
Consolute Temperature ◽  
Liquid Sampling

The quasi-reduced iron–selenium phase diagram has been determined by a combination of differential thermal analysis, visual polythermal, and liquid sampling techniques. Iron and selenium form two compounds: FeSe2 with a broad stoichiometry range and FeSe2 with a much narrower composition field. The former compound was found to melt congruently at 1070 °C and 53.5 atomic % selenium, while the latter melted incongruently at 585 °C. Two liquid–liquid regions were observed in this system. One occurred above 790 °C from 73.9 atomic % selenium to about 99.92% selenium with a consolute temperature of 1070 °C at approximately 93 atomic % selenium. The other liquid–liquid region extends upwards from 1520 °C and lies between 3 and 39.5 atomic % selenium.

Sepiolite at a locality in the Keuper Marl of the Midlands

1956 ◽  
Vol 31 (235) ◽  
pp. 328-332 ◽  
Author(s):  
P. S. Keeling
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Analysis ◽  
Diffraction Data ◽  
Ferric Oxide ◽  
X Ray Diffraction ◽  
X Ray

SummarySepiolite has been identified in the Keuper Marl at a Midlands locality by X-ray diffraction data, electron microscopy, differential thermal analysis, and chemical analysis. It has been calculated that a sample representing 30 ft. thickness of clay may contain as much as 39 % sepiolite. Apart from sepiolite, the Keuper Marl in the area examined consists mainly of mica, quartz, calcite, and ferric oxide.

scholarly journals Synthesis and thermal studies of solid state 2-chloro-benzylidenepyruvic acid and its compounds with sodium, aluminium (III), gallium (III) and indium (III) cations

2004 ◽  
Vol 29 (1) ◽  
pp. 31-40 ◽  
Author(s):  
G. Bannach ◽  
E. Schnitzler ◽  
C. B. Melios ◽  
M. Ionashiro
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Differential Thermal Analysis ◽  
Solid State ◽  
Chemical Analysis ◽  
Thermal Behaviour ◽  
Thermal Studies ◽  
X Ray ◽  
Derivative Thermogravimetry

The synthesis of sodium 2-chlorobenzylidenepyruvate and its corresponding acid as well as binary, binary together with it's acid or hydroxo-2-chorobenzylidenepyruvate of aluminium (III), gallium (III) and indium (III), were isolated. Chemical analysis, thermogravimetry, derivative thermogravimetry (TG/DTG), simultaneous thermogravimetry-differential thermal analysis (TG-DTA) and X-ray powder diffractometry have been employed to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the stoichiometry, crystallinity, thermal stability and thermal decomposition.

scholarly journals Determination of the Order of Kinetics of a DTA Curve by Using the Concept of Skewness

2020 ◽  
Vol 36 (6) ◽  
pp. 1235-1239
Author(s):  
BIKASH KUMAR SARKAR ◽  
INDRANIL BHATTACHARYYA ◽  
ANANDA SARKAR ◽  
PARTHA SARATHI MAJUMDAR
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
First Order ◽  
Positive Skewness ◽  
Order Of Kinetics ◽  
Negative Skewness ◽  
Dta Curves ◽  
Dta Curve ◽  
Kinetics Of

In the present paper, a novel way of finding out the order of kinetics of differential thermal analysis (DTA) curves by using the concept of skewness (Sk) has been investigated. It is found that for a particular DTA peak, skewness is a function of both the order of kinetics and the quantity, First order DTA peaks are characterized by negative skewness whereas those for the second order are characterized by positive skewness. Therefore, skewness can be used as an indicator of the order of kinetics of a DTA peak. We have evaluated and compared the orders of kinetics of some reported DTA peaks using the concept of skewness and found that the resulting values of the orders of kinetics are in fair agreement with those reported in literature.

Interaction of Kaolinite with Calcite on Heating: III. Effect of Different Kaolinites

Clay Minerals ◽  
1988 ◽  
Vol 23 (2) ◽  
pp. 191-203 ◽  
Author(s):  
R. C. Mackenzie ◽  
L. Heller-Kallai ◽  
A. A. Rahman ◽  
H. M. Moir
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
High Temperature ◽  
Room Temperature ◽  
General Relationship ◽  
Experimental Conditions ◽  
Tentative Explanation ◽  
General Locality ◽  
Dta Curves

AbstractThe degree of distortion of the calcite endotherm on differential thermal analysis (DTA) curves for kaolinite-calcite mixtures depends on the kaolinite sample used as well as on the factors previously established. Although no two of the ten kaolinite samples employed, even if from the same general locality, produced identical effects under all experimental conditions, a general relationship between locality of origin and degree of distortion was noted. The crystalline species detected in the products of heating, after standing in air at room temperature, included portlandite, calcite, aragonite, vaterite and the high-temperature phases gehlenite, α′-Ca2SiO4, and 12CaO. 7Al2O3. The actual species present again depended on the kaolinite sample. Although the results cannot be directly related to the volatiles evolved along with water on dehydroxylation of the different kaolinites, a tentative explanation is offered on the basis of the effects of the volatiles on the surfaces of the particles present.

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