Assessment of intensive grinding effects on alumina as refractory compound: Acceleration of gamma to alpha phase transformation mechanism
Abstract
In this study, the feasibility of alumina phase transition enhancement by mechanical activation was conducted. It was showed that the milling environment plays an important role on the physical, chemical and thermal behavior of the alumina powder utilized as refractory component material. The aim of the investigation was to increase the reactivity of the starting gamma-Al2O3 by mechanical treatment in two types of high-energy activators - vibratory disc mill and vibratory ball mill. In continuation, the decrease of the subsequent sintering temperature as well as the treatment duration would be induced by making the transition into final thermo-stable alpha-Al2O3 modification easier and faster. Full factorial experiment was conducted and the results were analyzed by the proposed mathematical model in order to understand the effects of the activation process variables on the amount and physical characteristics of the synthesized (activated and subsequently thermally treated) product and ...to establish the optimal activation period. As the result of the analysis, operation parameters of the activator and activation period were found to be the most important factors. The initial gamma-Al2O3 and synthesized alpha-Al2O3 were thoroughly analyzed by DTA, XRD, IR and SEM methods. Thermal behavior of gamma and alpha-modification were studied by differential thermal analysis conducted in the same environment, under same heating rates. X-ray diffraction analysis gave reliable identification of the crystal phases and changes in crystallinity of treated alumina. Based on XRD peak intensity measurements, the gamma-Al2O3 almost completely passed (95%) into alpha-Al2O3 after 180 min of activation in vibratory ball mill and subsequent thermal treatment (2 h/1200 degrees C). SEM microphotographs with accompanying image analysis PC program highlighted changes in size and shape of particles of initial and synthesized Al2O3. Synthesized Al2O3 exquisite thermal behavior characteristic for refractory compounds, demonstrated that it is possible to obtain alpha-alumina at lower transformation temperatures in shorter time intervals by applying mechanical activation.
Keywords:
Vibratory mill / Synthesized Al2O3 / Sintering / Refractory materials / Mechanical activationSource:
Ceramics International, 2014, 40, 9, 14851-14863Publisher:
- Elsevier Sci Ltd, Oxford
Funding / projects:
- Directed synthesis, structure and properties of multifunctional materials (RS-172057)
- Development and application of multifunctional materials using domestic raw materials in upgraded processing lines (RS-45008)
- Mechanochemistry treatment of low quality mineral raw materials (RS-34006)
DOI: 10.1016/j.ceramint.2014.06.080
ISSN: 0272-8842
WoS: 000341343300039
Scopus: 2-s2.0-84905902298
Collections
Institution/Community
Institut za ispitivanje materijalaTY - JOUR AU - Terzić, Anja AU - Andrić, Ljubiša AU - Mitić, Vojislav PY - 2014 UR - http://rims.institutims.rs/handle/123456789/243 AB - In this study, the feasibility of alumina phase transition enhancement by mechanical activation was conducted. It was showed that the milling environment plays an important role on the physical, chemical and thermal behavior of the alumina powder utilized as refractory component material. The aim of the investigation was to increase the reactivity of the starting gamma-Al2O3 by mechanical treatment in two types of high-energy activators - vibratory disc mill and vibratory ball mill. In continuation, the decrease of the subsequent sintering temperature as well as the treatment duration would be induced by making the transition into final thermo-stable alpha-Al2O3 modification easier and faster. Full factorial experiment was conducted and the results were analyzed by the proposed mathematical model in order to understand the effects of the activation process variables on the amount and physical characteristics of the synthesized (activated and subsequently thermally treated) product and to establish the optimal activation period. As the result of the analysis, operation parameters of the activator and activation period were found to be the most important factors. The initial gamma-Al2O3 and synthesized alpha-Al2O3 were thoroughly analyzed by DTA, XRD, IR and SEM methods. Thermal behavior of gamma and alpha-modification were studied by differential thermal analysis conducted in the same environment, under same heating rates. X-ray diffraction analysis gave reliable identification of the crystal phases and changes in crystallinity of treated alumina. Based on XRD peak intensity measurements, the gamma-Al2O3 almost completely passed (95%) into alpha-Al2O3 after 180 min of activation in vibratory ball mill and subsequent thermal treatment (2 h/1200 degrees C). SEM microphotographs with accompanying image analysis PC program highlighted changes in size and shape of particles of initial and synthesized Al2O3. Synthesized Al2O3 exquisite thermal behavior characteristic for refractory compounds, demonstrated that it is possible to obtain alpha-alumina at lower transformation temperatures in shorter time intervals by applying mechanical activation. PB - Elsevier Sci Ltd, Oxford T2 - Ceramics International T1 - Assessment of intensive grinding effects on alumina as refractory compound: Acceleration of gamma to alpha phase transformation mechanism EP - 14863 IS - 9 SP - 14851 VL - 40 DO - 10.1016/j.ceramint.2014.06.080 ER -
@article{ author = "Terzić, Anja and Andrić, Ljubiša and Mitić, Vojislav", year = "2014", abstract = "In this study, the feasibility of alumina phase transition enhancement by mechanical activation was conducted. It was showed that the milling environment plays an important role on the physical, chemical and thermal behavior of the alumina powder utilized as refractory component material. The aim of the investigation was to increase the reactivity of the starting gamma-Al2O3 by mechanical treatment in two types of high-energy activators - vibratory disc mill and vibratory ball mill. In continuation, the decrease of the subsequent sintering temperature as well as the treatment duration would be induced by making the transition into final thermo-stable alpha-Al2O3 modification easier and faster. Full factorial experiment was conducted and the results were analyzed by the proposed mathematical model in order to understand the effects of the activation process variables on the amount and physical characteristics of the synthesized (activated and subsequently thermally treated) product and to establish the optimal activation period. As the result of the analysis, operation parameters of the activator and activation period were found to be the most important factors. The initial gamma-Al2O3 and synthesized alpha-Al2O3 were thoroughly analyzed by DTA, XRD, IR and SEM methods. Thermal behavior of gamma and alpha-modification were studied by differential thermal analysis conducted in the same environment, under same heating rates. X-ray diffraction analysis gave reliable identification of the crystal phases and changes in crystallinity of treated alumina. Based on XRD peak intensity measurements, the gamma-Al2O3 almost completely passed (95%) into alpha-Al2O3 after 180 min of activation in vibratory ball mill and subsequent thermal treatment (2 h/1200 degrees C). SEM microphotographs with accompanying image analysis PC program highlighted changes in size and shape of particles of initial and synthesized Al2O3. Synthesized Al2O3 exquisite thermal behavior characteristic for refractory compounds, demonstrated that it is possible to obtain alpha-alumina at lower transformation temperatures in shorter time intervals by applying mechanical activation.", publisher = "Elsevier Sci Ltd, Oxford", journal = "Ceramics International", title = "Assessment of intensive grinding effects on alumina as refractory compound: Acceleration of gamma to alpha phase transformation mechanism", pages = "14863-14851", number = "9", volume = "40", doi = "10.1016/j.ceramint.2014.06.080" }
Terzić, A., Andrić, L.,& Mitić, V.. (2014). Assessment of intensive grinding effects on alumina as refractory compound: Acceleration of gamma to alpha phase transformation mechanism. in Ceramics International Elsevier Sci Ltd, Oxford., 40(9), 14851-14863. https://doi.org/10.1016/j.ceramint.2014.06.080
Terzić A, Andrić L, Mitić V. Assessment of intensive grinding effects on alumina as refractory compound: Acceleration of gamma to alpha phase transformation mechanism. in Ceramics International. 2014;40(9):14851-14863. doi:10.1016/j.ceramint.2014.06.080 .
Terzić, Anja, Andrić, Ljubiša, Mitić, Vojislav, "Assessment of intensive grinding effects on alumina as refractory compound: Acceleration of gamma to alpha phase transformation mechanism" in Ceramics International, 40, no. 9 (2014):14851-14863, https://doi.org/10.1016/j.ceramint.2014.06.080 . .