Obradović, Nina

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orcid::0000-0002-7993-293X
  • Obradović, Nina (7)
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Author's Bibliography

Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics

Terzić, Anja; Obradović, Nina; Kosanović, Darko; Stojanović, Jovica; Đorđević, Antonije; Andrić, Ljubiša; Pavlović, Vladimir

(Elsevier Sci Ltd, Oxford, 2019)

TY  - JOUR
AU  - Terzić, Anja
AU  - Obradović, Nina
AU  - Kosanović, Darko
AU  - Stojanović, Jovica
AU  - Đorđević, Antonije
AU  - Andrić, Ljubiša
AU  - Pavlović, Vladimir
PY  - 2019
UR  - http://rims.institutims.rs/handle/123456789/373
AB  - Steatite, as ceramic with composition predominantly resting on magnesium silicate, was produced from economic resources - talc, aluminosilicate clays, and either BaCO3 or feldspar as flux. Titanium dioxide was a doping agent. Four steatite mixtures were mechanically activated in a planetary ball mill for 30, 45 or 60 min, prior to the thermal treatment. Two-step sintering with initial phase set at 1350 degrees C and holding period conducted at 1250 degrees C was applied to initiate diffusion and prevent grain growth. Thereby, a high density ceramic material with low-porous submicron structure was acquired. The effects of TiO2 addition on densification, microstructure, and dielectric characteristics of steatites were monitored. The thermal stability of green mixtures was tested by differential thermal and thermogravimetric analyses. Changes in crystallinity and mineral phase composition were observed by the X-ray diffraction technique. Microstructural visualization with spatial arrangements of individual chemical elements on surface of the sintered ceramics was acquired by scanning electron microscopy accompanied with EDS mapping. In order to test the possibility of employment of the obtained steatites in insulation materials, electrical measurements were conducted by recording variations of the dielectric constant and loss tangent as a function of alternations in the mix-design and the mechanical activation period.
PB  - Elsevier Sci Ltd, Oxford
T2  - Ceramics International
T1  - Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics
EP  - 3022
IS  - 3
SP  - 3013
VL  - 45
DO  - 10.1016/j.ceramint.2018.10.120
ER  - 
@article{
author = "Terzić, Anja and Obradović, Nina and Kosanović, Darko and Stojanović, Jovica and Đorđević, Antonije and Andrić, Ljubiša and Pavlović, Vladimir",
year = "2019",
abstract = "Steatite, as ceramic with composition predominantly resting on magnesium silicate, was produced from economic resources - talc, aluminosilicate clays, and either BaCO3 or feldspar as flux. Titanium dioxide was a doping agent. Four steatite mixtures were mechanically activated in a planetary ball mill for 30, 45 or 60 min, prior to the thermal treatment. Two-step sintering with initial phase set at 1350 degrees C and holding period conducted at 1250 degrees C was applied to initiate diffusion and prevent grain growth. Thereby, a high density ceramic material with low-porous submicron structure was acquired. The effects of TiO2 addition on densification, microstructure, and dielectric characteristics of steatites were monitored. The thermal stability of green mixtures was tested by differential thermal and thermogravimetric analyses. Changes in crystallinity and mineral phase composition were observed by the X-ray diffraction technique. Microstructural visualization with spatial arrangements of individual chemical elements on surface of the sintered ceramics was acquired by scanning electron microscopy accompanied with EDS mapping. In order to test the possibility of employment of the obtained steatites in insulation materials, electrical measurements were conducted by recording variations of the dielectric constant and loss tangent as a function of alternations in the mix-design and the mechanical activation period.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Ceramics International",
title = "Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics",
pages = "3022-3013",
number = "3",
volume = "45",
doi = "10.1016/j.ceramint.2018.10.120"
}
Terzić, A., Obradović, N., Kosanović, D., Stojanović, J., Đorđević, A., Andrić, L.,& Pavlović, V.. (2019). Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics. in Ceramics International
Elsevier Sci Ltd, Oxford., 45(3), 3013-3022.
https://doi.org/10.1016/j.ceramint.2018.10.120
Terzić A, Obradović N, Kosanović D, Stojanović J, Đorđević A, Andrić L, Pavlović V. Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics. in Ceramics International. 2019;45(3):3013-3022.
doi:10.1016/j.ceramint.2018.10.120 .
Terzić, Anja, Obradović, Nina, Kosanović, Darko, Stojanović, Jovica, Đorđević, Antonije, Andrić, Ljubiša, Pavlović, Vladimir, "Effects of mechanical-activation and TiO2 addition on the behavior of two-step sintered steatite ceramics" in Ceramics International, 45, no. 3 (2019):3013-3022,
https://doi.org/10.1016/j.ceramint.2018.10.120 . .
1
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2

Microstructure and Phase Composition Of Steatite Ceramics Sintered by Traditional and Spark Plasma Sintering

Terzić, Anja; Obradović, Nina; Pouchly, Vaclav; Stojanović, Jovica; Maca, Karel; Pavlović, Vladimir

(Međunarodni Institut za nauku o sinterovanju, Beograd, 2018)

TY  - JOUR
AU  - Terzić, Anja
AU  - Obradović, Nina
AU  - Pouchly, Vaclav
AU  - Stojanović, Jovica
AU  - Maca, Karel
AU  - Pavlović, Vladimir
PY  - 2018
UR  - http://rims.institutims.rs/handle/123456789/340
AB  - The influence of the sintering method on the mineral phase transformations and development of the crystalline microstructure of steatite ceramics was investigated. The steatite samples were fabricated from talc and bentonite as low-cost raw materials. Feldspar and barium carbonate, as fluxing agents, were altered in the steatite composition. Dilatometric analysis was applied in the monitoring of the dimensional changes and thereby densification of steatite during the traditional sintering (TS) procedure up to 1200 degrees C. Spark plasma sintering (SPS) method was used under the following sintering conditions: 100 degrees C/min heating rate, uniaxial pressure of 50 MPa; sintering temperature 800 degrees C/1 min or 1000 degrees C/2 min. Crystallinity changes and mineral phase transition during sintering were observed by X-ray diffraction technique. Microstructural visualization of the samples and the spatial arrangements of individual chemical elements were achieved via scanning electron microscopy equipped with the EDS mapping. It was found that SPS sintering facilitated all microstructural changes during high temperature treatment and shifted them to lower temperatures. SPS treatment conducted at 1000 degrees C resulted in maximum densification of the steatite powder compacts and the formation stabilized protoenstatite structure.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Microstructure and Phase Composition Of Steatite Ceramics Sintered by Traditional and Spark Plasma Sintering
EP  - 312
IS  - 3
SP  - 299
VL  - 50
DO  - 10.2298/SOS1803299T
ER  - 
@article{
author = "Terzić, Anja and Obradović, Nina and Pouchly, Vaclav and Stojanović, Jovica and Maca, Karel and Pavlović, Vladimir",
year = "2018",
abstract = "The influence of the sintering method on the mineral phase transformations and development of the crystalline microstructure of steatite ceramics was investigated. The steatite samples were fabricated from talc and bentonite as low-cost raw materials. Feldspar and barium carbonate, as fluxing agents, were altered in the steatite composition. Dilatometric analysis was applied in the monitoring of the dimensional changes and thereby densification of steatite during the traditional sintering (TS) procedure up to 1200 degrees C. Spark plasma sintering (SPS) method was used under the following sintering conditions: 100 degrees C/min heating rate, uniaxial pressure of 50 MPa; sintering temperature 800 degrees C/1 min or 1000 degrees C/2 min. Crystallinity changes and mineral phase transition during sintering were observed by X-ray diffraction technique. Microstructural visualization of the samples and the spatial arrangements of individual chemical elements were achieved via scanning electron microscopy equipped with the EDS mapping. It was found that SPS sintering facilitated all microstructural changes during high temperature treatment and shifted them to lower temperatures. SPS treatment conducted at 1000 degrees C resulted in maximum densification of the steatite powder compacts and the formation stabilized protoenstatite structure.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Microstructure and Phase Composition Of Steatite Ceramics Sintered by Traditional and Spark Plasma Sintering",
pages = "312-299",
number = "3",
volume = "50",
doi = "10.2298/SOS1803299T"
}
Terzić, A., Obradović, N., Pouchly, V., Stojanović, J., Maca, K.,& Pavlović, V.. (2018). Microstructure and Phase Composition Of Steatite Ceramics Sintered by Traditional and Spark Plasma Sintering. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 50(3), 299-312.
https://doi.org/10.2298/SOS1803299T
Terzić A, Obradović N, Pouchly V, Stojanović J, Maca K, Pavlović V. Microstructure and Phase Composition Of Steatite Ceramics Sintered by Traditional and Spark Plasma Sintering. in Science of Sintering. 2018;50(3):299-312.
doi:10.2298/SOS1803299T .
Terzić, Anja, Obradović, Nina, Pouchly, Vaclav, Stojanović, Jovica, Maca, Karel, Pavlović, Vladimir, "Microstructure and Phase Composition Of Steatite Ceramics Sintered by Traditional and Spark Plasma Sintering" in Science of Sintering, 50, no. 3 (2018):299-312,
https://doi.org/10.2298/SOS1803299T . .
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Influence of different bonding and fluxing agents on the sintering behavior and dielectric properties of steatite ceramic materials

Terzić, Anja; Obradović, Nina; Stojanović, Jovica; Pavlović, Vladimir; Andrić, Ljubiša; Olcan, Dragan; Đorđević, Antonije

(Elsevier Sci Ltd, Oxford, 2017)

TY  - JOUR
AU  - Terzić, Anja
AU  - Obradović, Nina
AU  - Stojanović, Jovica
AU  - Pavlović, Vladimir
AU  - Andrić, Ljubiša
AU  - Olcan, Dragan
AU  - Đorđević, Antonije
PY  - 2017
UR  - http://rims.institutims.rs/handle/123456789/314
AB  - The focus of the study was on providing insights into interconnections between sintering and development of the crystalline microstructure, and consequently variations in dielectric behavior of four steatites fabricated from a low-cost raw material, i.e. talc. The changes, induced by the alternations of the binders (bentonite, kaolin clay) and fluxing agents (BaCO3, feldspar), were monitored in the temperature range 1000 degrees to 1250 degrees C in which complete densification and re-crystallization of the investigated structures were accomplished. The critical points in the synthesis of steatite materials were assessed by instrumental analyses. Crystallinity changes and mineral phase transition during sintering were monitored by X-ray diffraction technique. Microstructural visualization of the samples and the spatial arrangements of individual chemical elements were achieved via scanning electron microscopy accompanied with EDS mapping. The thermal stability was observed on the green mixtures using differential thermal and thermo gravimetric analyses. Electrical measurements recorded variations of the dielectric constant (epsilon(r)) and loss tangent (tan delta) as a function of the sintering temperature. The investigation highlighted critical design points, as well as the optimal combinations of the raw materials for production of the steatite ceramics for advanced electrical engineering applications.
PB  - Elsevier Sci Ltd, Oxford
T2  - Ceramics International
T1  - Influence of different bonding and fluxing agents on the sintering behavior and dielectric properties of steatite ceramic materials
EP  - 13275
IS  - 16
SP  - 13264
VL  - 43
DO  - 10.1016/j.ceramint.2017.07.024
ER  - 
@article{
author = "Terzić, Anja and Obradović, Nina and Stojanović, Jovica and Pavlović, Vladimir and Andrić, Ljubiša and Olcan, Dragan and Đorđević, Antonije",
year = "2017",
abstract = "The focus of the study was on providing insights into interconnections between sintering and development of the crystalline microstructure, and consequently variations in dielectric behavior of four steatites fabricated from a low-cost raw material, i.e. talc. The changes, induced by the alternations of the binders (bentonite, kaolin clay) and fluxing agents (BaCO3, feldspar), were monitored in the temperature range 1000 degrees to 1250 degrees C in which complete densification and re-crystallization of the investigated structures were accomplished. The critical points in the synthesis of steatite materials were assessed by instrumental analyses. Crystallinity changes and mineral phase transition during sintering were monitored by X-ray diffraction technique. Microstructural visualization of the samples and the spatial arrangements of individual chemical elements were achieved via scanning electron microscopy accompanied with EDS mapping. The thermal stability was observed on the green mixtures using differential thermal and thermo gravimetric analyses. Electrical measurements recorded variations of the dielectric constant (epsilon(r)) and loss tangent (tan delta) as a function of the sintering temperature. The investigation highlighted critical design points, as well as the optimal combinations of the raw materials for production of the steatite ceramics for advanced electrical engineering applications.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Ceramics International",
title = "Influence of different bonding and fluxing agents on the sintering behavior and dielectric properties of steatite ceramic materials",
pages = "13275-13264",
number = "16",
volume = "43",
doi = "10.1016/j.ceramint.2017.07.024"
}
Terzić, A., Obradović, N., Stojanović, J., Pavlović, V., Andrić, L., Olcan, D.,& Đorđević, A.. (2017). Influence of different bonding and fluxing agents on the sintering behavior and dielectric properties of steatite ceramic materials. in Ceramics International
Elsevier Sci Ltd, Oxford., 43(16), 13264-13275.
https://doi.org/10.1016/j.ceramint.2017.07.024
Terzić A, Obradović N, Stojanović J, Pavlović V, Andrić L, Olcan D, Đorđević A. Influence of different bonding and fluxing agents on the sintering behavior and dielectric properties of steatite ceramic materials. in Ceramics International. 2017;43(16):13264-13275.
doi:10.1016/j.ceramint.2017.07.024 .
Terzić, Anja, Obradović, Nina, Stojanović, Jovica, Pavlović, Vladimir, Andrić, Ljubiša, Olcan, Dragan, Đorđević, Antonije, "Influence of different bonding and fluxing agents on the sintering behavior and dielectric properties of steatite ceramic materials" in Ceramics International, 43, no. 16 (2017):13264-13275,
https://doi.org/10.1016/j.ceramint.2017.07.024 . .
10
4
10

Investigation of thermally induced processes in corundum refractory concretes with addition of fly ash

Terzić, Anja; Obradović, Nina; Andrić, Ljubiša; Stojanović, Jovica; Pavlović, Vladimir

(Springer, Dordrecht, 2015)

TY  - JOUR
AU  - Terzić, Anja
AU  - Obradović, Nina
AU  - Andrić, Ljubiša
AU  - Stojanović, Jovica
AU  - Pavlović, Vladimir
PY  - 2015
UR  - http://rims.institutims.rs/handle/123456789/266
AB  - The effects that the fly ash addition has on the behavior of thermally resistant corundum concrete were discussed. Experimental program implied production of two refractory composites: "referent" concrete from 20 % of high-aluminate cement and 80 % of corundum aggregate, "recycled" concrete from 10 % of high-aluminate cement, 20 % of lignite coal ash, and 70 % of corundum aggregate. The fly ash was mechanically activated by a vibratory disk mill. In the concrete matrix, the ash had a role of cement partial replacement and microfiller. The mechanical and thermal properties of the concretes were studied at temperatures ranging from ambient to 1,400 A degrees C as adopted maximum. Mechanisms of thermally induced processes were observed by differential thermal analysis at 10, 20, and 30 A degrees C min(-1) heating rates. Referent and recycled concretes showed differences in calculated activation energies. The variations in refractory concretes performances were discussed with support of scanning electron microscope imagining and X-ray diffraction results. The recycled ash concrete exhibited properties that met the requirements for the castables, which proves it suitable for use in severe conditions at high temperature and highlights the reusing principle and possibility of cleaner and economically sustainable production.
PB  - Springer, Dordrecht
T2  - Journal of Thermal Analysis and Calorimetry
T1  - Investigation of thermally induced processes in corundum refractory concretes with addition of fly ash
EP  - 1352
IS  - 2
SP  - 1339
VL  - 119
DO  - 10.1007/s10973-014-4230-4
ER  - 
@article{
author = "Terzić, Anja and Obradović, Nina and Andrić, Ljubiša and Stojanović, Jovica and Pavlović, Vladimir",
year = "2015",
abstract = "The effects that the fly ash addition has on the behavior of thermally resistant corundum concrete were discussed. Experimental program implied production of two refractory composites: "referent" concrete from 20 % of high-aluminate cement and 80 % of corundum aggregate, "recycled" concrete from 10 % of high-aluminate cement, 20 % of lignite coal ash, and 70 % of corundum aggregate. The fly ash was mechanically activated by a vibratory disk mill. In the concrete matrix, the ash had a role of cement partial replacement and microfiller. The mechanical and thermal properties of the concretes were studied at temperatures ranging from ambient to 1,400 A degrees C as adopted maximum. Mechanisms of thermally induced processes were observed by differential thermal analysis at 10, 20, and 30 A degrees C min(-1) heating rates. Referent and recycled concretes showed differences in calculated activation energies. The variations in refractory concretes performances were discussed with support of scanning electron microscope imagining and X-ray diffraction results. The recycled ash concrete exhibited properties that met the requirements for the castables, which proves it suitable for use in severe conditions at high temperature and highlights the reusing principle and possibility of cleaner and economically sustainable production.",
publisher = "Springer, Dordrecht",
journal = "Journal of Thermal Analysis and Calorimetry",
title = "Investigation of thermally induced processes in corundum refractory concretes with addition of fly ash",
pages = "1352-1339",
number = "2",
volume = "119",
doi = "10.1007/s10973-014-4230-4"
}
Terzić, A., Obradović, N., Andrić, L., Stojanović, J.,& Pavlović, V.. (2015). Investigation of thermally induced processes in corundum refractory concretes with addition of fly ash. in Journal of Thermal Analysis and Calorimetry
Springer, Dordrecht., 119(2), 1339-1352.
https://doi.org/10.1007/s10973-014-4230-4
Terzić A, Obradović N, Andrić L, Stojanović J, Pavlović V. Investigation of thermally induced processes in corundum refractory concretes with addition of fly ash. in Journal of Thermal Analysis and Calorimetry. 2015;119(2):1339-1352.
doi:10.1007/s10973-014-4230-4 .
Terzić, Anja, Obradović, Nina, Andrić, Ljubiša, Stojanović, Jovica, Pavlović, Vladimir, "Investigation of thermally induced processes in corundum refractory concretes with addition of fly ash" in Journal of Thermal Analysis and Calorimetry, 119, no. 2 (2015):1339-1352,
https://doi.org/10.1007/s10973-014-4230-4 . .
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8

Mechanical Activation as Sintering Pre-treatment of Talc for Steatite Ceramics

Terzić, Anja; Andrić, Ljubiša; Stojanović, Jovica; Obradović, Nina; Kostović, Milena

(Međunarodni Institut za nauku o sinterovanju, Beograd, 2014)

TY  - JOUR
AU  - Terzić, Anja
AU  - Andrić, Ljubiša
AU  - Stojanović, Jovica
AU  - Obradović, Nina
AU  - Kostović, Milena
PY  - 2014
UR  - http://rims.institutims.rs/handle/123456789/236
AB  - The effect of vibratory mill induced mechanical activation on the change of the particle size, crystallinity and the phase transformations of the minerals present in the activated material, was studied with the purpose of decreasing of the sintering temperature of talc (Mg3Si4O10(OH)(2)) as raw material which is the basic component of the steatite ceramics. The aims of the conducted investigation were, also, increasing of the reactivity of the comminuted raw material and establishing of the optimal activation period. The properties of the activated talc induced by mechanical force were expressed in form of the grain inertia change which was measured by means of automatic grain counter. Mechanically activated grains are the most convenient mineral form for physical concentration since the energy change of the mill-material system is recorded on them. The effect of dry grinding on the structure, particle size and shape of talc was studied by means of XRD, DTA and SEM/EDS methods. Activation of talc produced an increase of the starting surface area value progressively from 4.5 m(2)/g up to a maximum of 108.5 m(2)/g achieved at 30 min. A subsequent decrease of rate of surface area change and the rate of size reduction were observed following the prolonged grinding. Talc activated in vibratory mill for optimal 30 min showed properties which positively influence the decrease of sintering temperature and the increase of the sintering rate of steatite ceramics.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Mechanical Activation as Sintering Pre-treatment of Talc for Steatite Ceramics
EP  - 258
IS  - 2
SP  - 247
VL  - 46
DO  - 10.2298/SOS1402247T
ER  - 
@article{
author = "Terzić, Anja and Andrić, Ljubiša and Stojanović, Jovica and Obradović, Nina and Kostović, Milena",
year = "2014",
abstract = "The effect of vibratory mill induced mechanical activation on the change of the particle size, crystallinity and the phase transformations of the minerals present in the activated material, was studied with the purpose of decreasing of the sintering temperature of talc (Mg3Si4O10(OH)(2)) as raw material which is the basic component of the steatite ceramics. The aims of the conducted investigation were, also, increasing of the reactivity of the comminuted raw material and establishing of the optimal activation period. The properties of the activated talc induced by mechanical force were expressed in form of the grain inertia change which was measured by means of automatic grain counter. Mechanically activated grains are the most convenient mineral form for physical concentration since the energy change of the mill-material system is recorded on them. The effect of dry grinding on the structure, particle size and shape of talc was studied by means of XRD, DTA and SEM/EDS methods. Activation of talc produced an increase of the starting surface area value progressively from 4.5 m(2)/g up to a maximum of 108.5 m(2)/g achieved at 30 min. A subsequent decrease of rate of surface area change and the rate of size reduction were observed following the prolonged grinding. Talc activated in vibratory mill for optimal 30 min showed properties which positively influence the decrease of sintering temperature and the increase of the sintering rate of steatite ceramics.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Mechanical Activation as Sintering Pre-treatment of Talc for Steatite Ceramics",
pages = "258-247",
number = "2",
volume = "46",
doi = "10.2298/SOS1402247T"
}
Terzić, A., Andrić, L., Stojanović, J., Obradović, N.,& Kostović, M.. (2014). Mechanical Activation as Sintering Pre-treatment of Talc for Steatite Ceramics. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 46(2), 247-258.
https://doi.org/10.2298/SOS1402247T
Terzić A, Andrić L, Stojanović J, Obradović N, Kostović M. Mechanical Activation as Sintering Pre-treatment of Talc for Steatite Ceramics. in Science of Sintering. 2014;46(2):247-258.
doi:10.2298/SOS1402247T .
Terzić, Anja, Andrić, Ljubiša, Stojanović, Jovica, Obradović, Nina, Kostović, Milena, "Mechanical Activation as Sintering Pre-treatment of Talc for Steatite Ceramics" in Science of Sintering, 46, no. 2 (2014):247-258,
https://doi.org/10.2298/SOS1402247T . .
8
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11

Synthesis and sintering of high-temperature composites based on mechanically activated fly ash

Terzić, Anja; Pavlović, Ljubica; Obradović, Nina; Pavlović, Vladimir; Stojanović, Jovica; Miličić, Ljiljana; Radojević, Zagorka; Ristić, M.M.

(Međunarodni Institut za nauku o sinterovanju, Beograd, 2012)

TY  - JOUR
AU  - Terzić, Anja
AU  - Pavlović, Ljubica
AU  - Obradović, Nina
AU  - Pavlović, Vladimir
AU  - Stojanović, Jovica
AU  - Miličić, Ljiljana
AU  - Radojević, Zagorka
AU  - Ristić, M.M.
PY  - 2012
UR  - http://rims.institutims.rs/handle/123456789/155
AB  - Količina letećeg pepela koji se proizvodi i koja će biti proizvedena u godinama koje dolaze zahteva razvoj novih metoda recikliranja u kojima će biti upotrebljene značajne količine ovog otpadnog materijala. Mogućnost visoko-temperaturne aplikacije (termoizolacioni i vatrostalni materijali) ukazuje na novu mogućnost za primenu letećeg pepela. Za takvu primenu leteći pepeo mora da zadovolji visoke mehaničke i termičke kriterijume. Jedan od načina da se to postigne je mehanička aktivacija letećeg pepela. U ovom radu prikazani su rezultati mehaničke aktivacije pepela iz dve različite termo-elektrane pomoću planetarnog mlina. Aktivirani pepeli su mešani sa dva veziva: portland cementom i visoko-aluminatnim cementom. Akcenat je na analizi fizičko-hemijskih svojstava i mineroloških faza zbog promena koje se dešavaju u kompozitima usled mehaničke aktivacije pepela i sinterovanja. Makro svojstva kompozita su povezana sa mikrostrukturom ispitivanom pomoću SEM analize i Rendgenske difrakcije. Termijska stabilnost kristalnih faza ispitivana je pomoću DTA. Akcenat je na utvrđivanju korelacija između mehaničke aktivacije letećeg pepela i mikrostrukture kompozita na jednoj i svojstava sinterovanog kompozita na drugoj strani.
AB  - Amount of fly ash which is and yet to be generated in the coming years highlights the necessity of developing new methods of the recycling where this waste can be reused in significant quantity. A new possibility for fly ash utilization is in high-temperature application (thermal insulators or/and refractory material products). As such, fly ash has to adequately answer the mechanical and thermal stability criteria. One of the ways of achieving it is by applying mechanical activation procedure on fly ash. In present study, fly ashes from two different power plants were mechanically activated in a planetary ball mill. Mechanically treated fly ashes were cemented with two different binders: standard Portland cement and high-aluminates cement. Physico-chemical analysis and investigation of mineralogical components of composites are emphasized, due to the changes occurred in fly ash during mechanical activation and sintering of composites. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Thermal stability of crystalline phases was investigated with DTA. Highlight was placed on determination of relationship between mechanically activated fly ash and obtained composites microstructure on one side and behavior of sintered composites on the other side.
PB  - Međunarodni Institut za nauku o sinterovanju, Beograd
T2  - Science of Sintering
T1  - Synthesis and sintering of high-temperature composites based on mechanically activated fly ash
EP  - 146
IS  - 2
SP  - 135
VL  - 44
DO  - 10.2298/SOS1202135T
ER  - 
@article{
author = "Terzić, Anja and Pavlović, Ljubica and Obradović, Nina and Pavlović, Vladimir and Stojanović, Jovica and Miličić, Ljiljana and Radojević, Zagorka and Ristić, M.M.",
year = "2012",
abstract = "Količina letećeg pepela koji se proizvodi i koja će biti proizvedena u godinama koje dolaze zahteva razvoj novih metoda recikliranja u kojima će biti upotrebljene značajne količine ovog otpadnog materijala. Mogućnost visoko-temperaturne aplikacije (termoizolacioni i vatrostalni materijali) ukazuje na novu mogućnost za primenu letećeg pepela. Za takvu primenu leteći pepeo mora da zadovolji visoke mehaničke i termičke kriterijume. Jedan od načina da se to postigne je mehanička aktivacija letećeg pepela. U ovom radu prikazani su rezultati mehaničke aktivacije pepela iz dve različite termo-elektrane pomoću planetarnog mlina. Aktivirani pepeli su mešani sa dva veziva: portland cementom i visoko-aluminatnim cementom. Akcenat je na analizi fizičko-hemijskih svojstava i mineroloških faza zbog promena koje se dešavaju u kompozitima usled mehaničke aktivacije pepela i sinterovanja. Makro svojstva kompozita su povezana sa mikrostrukturom ispitivanom pomoću SEM analize i Rendgenske difrakcije. Termijska stabilnost kristalnih faza ispitivana je pomoću DTA. Akcenat je na utvrđivanju korelacija između mehaničke aktivacije letećeg pepela i mikrostrukture kompozita na jednoj i svojstava sinterovanog kompozita na drugoj strani., Amount of fly ash which is and yet to be generated in the coming years highlights the necessity of developing new methods of the recycling where this waste can be reused in significant quantity. A new possibility for fly ash utilization is in high-temperature application (thermal insulators or/and refractory material products). As such, fly ash has to adequately answer the mechanical and thermal stability criteria. One of the ways of achieving it is by applying mechanical activation procedure on fly ash. In present study, fly ashes from two different power plants were mechanically activated in a planetary ball mill. Mechanically treated fly ashes were cemented with two different binders: standard Portland cement and high-aluminates cement. Physico-chemical analysis and investigation of mineralogical components of composites are emphasized, due to the changes occurred in fly ash during mechanical activation and sintering of composites. Macro-performance of the composites was correlated to the microstructure of fly ash studied by means of XRD and SEM analysis. Thermal stability of crystalline phases was investigated with DTA. Highlight was placed on determination of relationship between mechanically activated fly ash and obtained composites microstructure on one side and behavior of sintered composites on the other side.",
publisher = "Međunarodni Institut za nauku o sinterovanju, Beograd",
journal = "Science of Sintering",
title = "Synthesis and sintering of high-temperature composites based on mechanically activated fly ash",
pages = "146-135",
number = "2",
volume = "44",
doi = "10.2298/SOS1202135T"
}
Terzić, A., Pavlović, L., Obradović, N., Pavlović, V., Stojanović, J., Miličić, L., Radojević, Z.,& Ristić, M.M.. (2012). Synthesis and sintering of high-temperature composites based on mechanically activated fly ash. in Science of Sintering
Međunarodni Institut za nauku o sinterovanju, Beograd., 44(2), 135-146.
https://doi.org/10.2298/SOS1202135T
Terzić A, Pavlović L, Obradović N, Pavlović V, Stojanović J, Miličić L, Radojević Z, Ristić M. Synthesis and sintering of high-temperature composites based on mechanically activated fly ash. in Science of Sintering. 2012;44(2):135-146.
doi:10.2298/SOS1202135T .
Terzić, Anja, Pavlović, Ljubica, Obradović, Nina, Pavlović, Vladimir, Stojanović, Jovica, Miličić, Ljiljana, Radojević, Zagorka, Ristić, M.M., "Synthesis and sintering of high-temperature composites based on mechanically activated fly ash" in Science of Sintering, 44, no. 2 (2012):135-146,
https://doi.org/10.2298/SOS1202135T . .
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Dehydration investigations of a refractory concrete using DTA method

Obradović, Nina; Terzić, Anja; Pavlović, Ljubica; Filipović, S.; Pavlović, Vladimir

(Springer, Dordrecht, 2012)

TY  - JOUR
AU  - Obradović, Nina
AU  - Terzić, Anja
AU  - Pavlović, Ljubica
AU  - Filipović, S.
AU  - Pavlović, Vladimir
PY  - 2012
UR  - http://rims.institutims.rs/handle/123456789/158
AB  - The base mix refractory concrete is corundum-based, containing corundum as refractory aggregate and CAC as hydraulic binder, with a spinel as an additive. The authors investigated the dehydration reactions which occur from the moment when water is added (at the beginning of components mixing), to the moment when installed refractory concrete lining is put into the service. Sintering process kinetic of low-cement content refractory concrete was investigated by means of differential thermal analysis at four different heating rates (5, 10, 20, and 30 A degrees C/min). Thus, temperature was increased from 20 to 1100 A degrees C. It was noticed that first dehydration step occurs at lower temperatures, indicating at a desorption of physically adsorbed and interlayer water molecules. Second dehydration step, at higher temperatures is due to dehydroxylation of the lattices and decomposition of the interlayer anions.
PB  - Springer, Dordrecht
T2  - Journal of Thermal Analysis and Calorimetry
T1  - Dehydration investigations of a refractory concrete using DTA method
EP  - 41
IS  - 1
SP  - 37
VL  - 110
DO  - 10.1007/s10973-011-1880-3
ER  - 
@article{
author = "Obradović, Nina and Terzić, Anja and Pavlović, Ljubica and Filipović, S. and Pavlović, Vladimir",
year = "2012",
abstract = "The base mix refractory concrete is corundum-based, containing corundum as refractory aggregate and CAC as hydraulic binder, with a spinel as an additive. The authors investigated the dehydration reactions which occur from the moment when water is added (at the beginning of components mixing), to the moment when installed refractory concrete lining is put into the service. Sintering process kinetic of low-cement content refractory concrete was investigated by means of differential thermal analysis at four different heating rates (5, 10, 20, and 30 A degrees C/min). Thus, temperature was increased from 20 to 1100 A degrees C. It was noticed that first dehydration step occurs at lower temperatures, indicating at a desorption of physically adsorbed and interlayer water molecules. Second dehydration step, at higher temperatures is due to dehydroxylation of the lattices and decomposition of the interlayer anions.",
publisher = "Springer, Dordrecht",
journal = "Journal of Thermal Analysis and Calorimetry",
title = "Dehydration investigations of a refractory concrete using DTA method",
pages = "41-37",
number = "1",
volume = "110",
doi = "10.1007/s10973-011-1880-3"
}
Obradović, N., Terzić, A., Pavlović, L., Filipović, S.,& Pavlović, V.. (2012). Dehydration investigations of a refractory concrete using DTA method. in Journal of Thermal Analysis and Calorimetry
Springer, Dordrecht., 110(1), 37-41.
https://doi.org/10.1007/s10973-011-1880-3
Obradović N, Terzić A, Pavlović L, Filipović S, Pavlović V. Dehydration investigations of a refractory concrete using DTA method. in Journal of Thermal Analysis and Calorimetry. 2012;110(1):37-41.
doi:10.1007/s10973-011-1880-3 .
Obradović, Nina, Terzić, Anja, Pavlović, Ljubica, Filipović, S., Pavlović, Vladimir, "Dehydration investigations of a refractory concrete using DTA method" in Journal of Thermal Analysis and Calorimetry, 110, no. 1 (2012):37-41,
https://doi.org/10.1007/s10973-011-1880-3 . .
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