TY  - JOUR
AU  - Kamberović, Željko
AU  - Raić, Karlo
AU  - Filipović, Mirjana
AU  - Andić, Zoran
AU  - Korać, Marija
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2229
AB  - Presented study shows the analysis of the process of reduction of WO 3 powder with hydrogen in the vertical tube reactor, representing a new approach in comparison to the conventional methods in the horizontal tube reactor. SEM analysis of the synthetisized tungsten powder shows the existence of particles, approximately 1,mu m in size, both individual ones and those within the porous agglomerates with a spongy structure. In order to study the mechanism and kinetics of the reduction process, the reduction degree and retention time of particles of WO3 powder in the reaction zone were calculated using a developed mathematical model, based on the application of Stokes' law. Kinetic parameters and activation energies were determined at the corresponding temperature intervals. Kinetic analysis showed that the process of WO3 reduction with hydrogen in the vertical tube reactor in the temperature interval from 700 to 900 degrees C occurs in the kinetic zone. Activation energy for the temperature interval from 700 to 800 degrees C is E-a1=7.5 +/- 0.1 kJ/mol, whereas for the temperature interval from 800 to 900 degrees C, activation energy is E-a2=14.6 +/- 0.1 kJ/mol. A model was proposed describing the mechanism of the reduction process in the vertical tube reactor according to which particles of tungsten powder I pm in size arise from the stretching and cracking of coarse particles in the reduction zone, as well as from the appropriate temperature shock outside this zone.
PB  - Editura Stiintifica Fmr, Bucharest
T2  - Metalurgia International
T1  - The mechanism and kinetics of the tungsten (vi)-oxide reduction in the vertical tube reactor
EP  - 13
IS  - 4
SP  - 8
VL  - 17
UR  - https://hdl.handle.net/21.15107/rcub_technorep_2229
ER  - 

@article{
author = "Kamberović, Željko and Raić, Karlo and Filipović, Mirjana and Andić, Zoran and Korać, Marija",
year = "2012",
abstract = "Presented study shows the analysis of the process of reduction of WO 3 powder with hydrogen in the vertical tube reactor, representing a new approach in comparison to the conventional methods in the horizontal tube reactor. SEM analysis of the synthetisized tungsten powder shows the existence of particles, approximately 1,mu m in size, both individual ones and those within the porous agglomerates with a spongy structure. In order to study the mechanism and kinetics of the reduction process, the reduction degree and retention time of particles of WO3 powder in the reaction zone were calculated using a developed mathematical model, based on the application of Stokes' law. Kinetic parameters and activation energies were determined at the corresponding temperature intervals. Kinetic analysis showed that the process of WO3 reduction with hydrogen in the vertical tube reactor in the temperature interval from 700 to 900 degrees C occurs in the kinetic zone. Activation energy for the temperature interval from 700 to 800 degrees C is E-a1=7.5 +/- 0.1 kJ/mol, whereas for the temperature interval from 800 to 900 degrees C, activation energy is E-a2=14.6 +/- 0.1 kJ/mol. A model was proposed describing the mechanism of the reduction process in the vertical tube reactor according to which particles of tungsten powder I pm in size arise from the stretching and cracking of coarse particles in the reduction zone, as well as from the appropriate temperature shock outside this zone.",
publisher = "Editura Stiintifica Fmr, Bucharest",
journal = "Metalurgia International",
title = "The mechanism and kinetics of the tungsten (vi)-oxide reduction in the vertical tube reactor",
pages = "13-8",
number = "4",
volume = "17",
url = "https://hdl.handle.net/21.15107/rcub_technorep_2229"
}

Kamberović, Ž., Raić, K., Filipović, M., Andić, Z.,& Korać, M.. (2012). The mechanism and kinetics of the tungsten (vi)-oxide reduction in the vertical tube reactor. in Metalurgia International
Editura Stiintifica Fmr, Bucharest., 17(4), 8-13.
https://hdl.handle.net/21.15107/rcub_technorep_2229

Kamberović Ž, Raić K, Filipović M, Andić Z, Korać M. The mechanism and kinetics of the tungsten (vi)-oxide reduction in the vertical tube reactor. in Metalurgia International. 2012;17(4):8-13.
https://hdl.handle.net/21.15107/rcub_technorep_2229 .

Kamberović, Željko, Raić, Karlo, Filipović, Mirjana, Andić, Zoran, Korać, Marija, "The mechanism and kinetics of the tungsten (vi)-oxide reduction in the vertical tube reactor" in Metalurgia International, 17, no. 4 (2012):8-13,
https://hdl.handle.net/21.15107/rcub_technorep_2229 .

TY  - JOUR
AU  - Kamberović, Željko
AU  - Filipović, Dušica
AU  - Raić, Karlo
AU  - Tasić, Miloš
AU  - Andić, Zoran
AU  - Gavrilovski, Milorad
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1883
AB  - The reduction of WO(3) with hydrogen in a vertical tube reactor is a new approach to the reduction of tungsten oxide compared to conventional procedures in a stationary layer. The advantage of this method is the intensive contact between the reducent and the oxide particles, a higher degree and a shorter time of reduction of only a few seconds, compared to the several hours processing time in a horizontal tube reactor. The characterization of the WO(3) powder and of the tungsten powder included a SEM microstructural examination and DT/TG analyses. The SEM examination of the tungsten powder indicates the presence of small particles with a size of about 1 mu m, also within an agglomerated porous foam structure. Tungsten powder with a particle size of less than 1 mu m is obtained at an optimal temperature with a suitable flow of hydrogen, as a result of stretching and the cracking of large particles, first in the reaction zone, and then, due to appropriate shock of the temperature, outside of this zone. Using an appropriate mathematical model, the degree of reduction and the time required for the formation of tungsten particles during the hydrogen reduction of WO(3) in a vertical tube reactor were determined. Experimental studies have shown that the degree of reduction of WO(3) with hydrogen in a vertical tube reactor increases with the temperature and the flow of hydrogen.
PB  - Institute of Metals and Technology
T2  - Materiali in Tehnologije
T1  - Reduction of ultra-fine tungsten powder with tungsten (vi) oxide in a vertical tube reactor
EP  - 32
IS  - 1
SP  - 27
VL  - 45
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1883
ER  - 

@article{
author = "Kamberović, Željko and Filipović, Dušica and Raić, Karlo and Tasić, Miloš and Andić, Zoran and Gavrilovski, Milorad",
year = "2011",
abstract = "The reduction of WO(3) with hydrogen in a vertical tube reactor is a new approach to the reduction of tungsten oxide compared to conventional procedures in a stationary layer. The advantage of this method is the intensive contact between the reducent and the oxide particles, a higher degree and a shorter time of reduction of only a few seconds, compared to the several hours processing time in a horizontal tube reactor. The characterization of the WO(3) powder and of the tungsten powder included a SEM microstructural examination and DT/TG analyses. The SEM examination of the tungsten powder indicates the presence of small particles with a size of about 1 mu m, also within an agglomerated porous foam structure. Tungsten powder with a particle size of less than 1 mu m is obtained at an optimal temperature with a suitable flow of hydrogen, as a result of stretching and the cracking of large particles, first in the reaction zone, and then, due to appropriate shock of the temperature, outside of this zone. Using an appropriate mathematical model, the degree of reduction and the time required for the formation of tungsten particles during the hydrogen reduction of WO(3) in a vertical tube reactor were determined. Experimental studies have shown that the degree of reduction of WO(3) with hydrogen in a vertical tube reactor increases with the temperature and the flow of hydrogen.",
publisher = "Institute of Metals and Technology",
journal = "Materiali in Tehnologije",
title = "Reduction of ultra-fine tungsten powder with tungsten (vi) oxide in a vertical tube reactor",
pages = "32-27",
number = "1",
volume = "45",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1883"
}

Kamberović, Ž., Filipović, D., Raić, K., Tasić, M., Andić, Z.,& Gavrilovski, M.. (2011). Reduction of ultra-fine tungsten powder with tungsten (vi) oxide in a vertical tube reactor. in Materiali in Tehnologije
Institute of Metals and Technology., 45(1), 27-32.
https://hdl.handle.net/21.15107/rcub_technorep_1883

Kamberović Ž, Filipović D, Raić K, Tasić M, Andić Z, Gavrilovski M. Reduction of ultra-fine tungsten powder with tungsten (vi) oxide in a vertical tube reactor. in Materiali in Tehnologije. 2011;45(1):27-32.
https://hdl.handle.net/21.15107/rcub_technorep_1883 .

Kamberović, Željko, Filipović, Dušica, Raić, Karlo, Tasić, Miloš, Andić, Zoran, Gavrilovski, Milorad, "Reduction of ultra-fine tungsten powder with tungsten (vi) oxide in a vertical tube reactor" in Materiali in Tehnologije, 45, no. 1 (2011):27-32,
https://hdl.handle.net/21.15107/rcub_technorep_1883 .