TY - JOUR
T1 - Effects of grinding and firing conditions on CaAl2Si2O8 phase formation by solid-state reaction of kaolinite with CaCO3
AU - Okada, Kiyoshi
AU - Watanabe, Nagisa
AU - Jha, Kumar V.
AU - Kameshima, Yoshikazu
AU - Yasumori, Atsuo
AU - MacKenzie, Kenneth J.D.
N1 - Funding Information:
A part of this work was supported by The Japan Securities Scholarship Foundation. KVJ thanks the Ministry of Education, Science, Sports and Culture Japan for a Scholarship, under which this work was carried out.
PY - 2003/10
Y1 - 2003/10
N2 - The effects of grinding and firing conditions on CaAl2Si2O8 phase formation by solid-state reaction of kaolinite with CaCO3 were investigated by differential thermal analysis (DTA)-thermogravimetry (TG), X-ray powder diffraction (XRD) and 29Si and 27Al MAS NMR. Unground and ground samples showed similar crystallization behavior at about 850 °C, and the crystallizing temperature was relatively unaffected by grinding. On the other hand, the crystalline products were strongly influenced by the grinding. Gehlenite (Ca2Al2SiO7) was the dominant phase in the unground samples but layer-structured CaAl2Si2O8 was dominant in the ground samples, together with a small amount of anorthite, which is the stable phase. The amount of anorthite gradually increased with higher firing temperature, the sample fired at 1000 °C being almost completely anorthite. Grinding treatment before firing was effective in accelerating the decomposition of CaCO3 and extending the temperature range for the formation of CaAl2Si2O8, a phase with local structure similar to that of layered CaAl2Si2O8.
AB - The effects of grinding and firing conditions on CaAl2Si2O8 phase formation by solid-state reaction of kaolinite with CaCO3 were investigated by differential thermal analysis (DTA)-thermogravimetry (TG), X-ray powder diffraction (XRD) and 29Si and 27Al MAS NMR. Unground and ground samples showed similar crystallization behavior at about 850 °C, and the crystallizing temperature was relatively unaffected by grinding. On the other hand, the crystalline products were strongly influenced by the grinding. Gehlenite (Ca2Al2SiO7) was the dominant phase in the unground samples but layer-structured CaAl2Si2O8 was dominant in the ground samples, together with a small amount of anorthite, which is the stable phase. The amount of anorthite gradually increased with higher firing temperature, the sample fired at 1000 °C being almost completely anorthite. Grinding treatment before firing was effective in accelerating the decomposition of CaCO3 and extending the temperature range for the formation of CaAl2Si2O8, a phase with local structure similar to that of layered CaAl2Si2O8.
KW - CaAlSiO
KW - CaCO
KW - Kaolinite
KW - Layered structure
KW - Solid-state reaction
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U2 - 10.1016/S0169-1317(03)00132-7
DO - 10.1016/S0169-1317(03)00132-7
M3 - Article
AN - SCOPUS:0141640779
VL - 23
SP - 329
EP - 336
JO - Applied Clay Science
JF - Applied Clay Science
SN - 0169-1317
IS - 5-6
ER -