TY - JOUR
T1 - From Molten Calcium Aluminates through Phase Transitions to Cement Phases
AU - Liu, Hao
AU - Chen, Wenlin
AU - Pan, Ruikun
AU - Shan, Zhitao
AU - Qiao, Ang
AU - Drewitt, James W. E.
AU - Hennet, Louis
AU - Jahn, Sandro
AU - Langstaff, David P.
AU - Chass, Gregory A.
AU - Tao, Haizheng
AU - Yue, Yuanzheng
AU - Greaves, G.N.
PY - 2020/1/22
Y1 - 2020/1/22
N2 - Crystalline calcium aluminates are a critical setting agent in cement. To date, few have explored the microscopic and dynamic mechanism of the transitions from molten aluminate liquids, through the supercooled state to glassy and crystalline phases, during cement clinker production. Herein, the first in situ measurements of viscosity and density are reported across all the principal molten phases, relevant to their eventual crystalline structures. Bulk atomistic computer simulations confirm that thermophysical properties scale with the evolution of network substructures interpenetrating melts on the nanoscale. It is demonstrated that the glass transition temperature (Tg) follows the eutectic profile of the liquidus temperature (Tm), coinciding with the melting zone in cement production. The viscosity has been uniquely charted over 14 decades for each calcium-aluminate phase, projecting and justifying the different temperature zones used in cement manufacture. The fragile–strong phase transitions are revealed across all supercooled phases coinciding with heterogeneous nucleation close to 1.2Tg, where sintering and quenching occur in industrial-scale cement processing.
AB - Crystalline calcium aluminates are a critical setting agent in cement. To date, few have explored the microscopic and dynamic mechanism of the transitions from molten aluminate liquids, through the supercooled state to glassy and crystalline phases, during cement clinker production. Herein, the first in situ measurements of viscosity and density are reported across all the principal molten phases, relevant to their eventual crystalline structures. Bulk atomistic computer simulations confirm that thermophysical properties scale with the evolution of network substructures interpenetrating melts on the nanoscale. It is demonstrated that the glass transition temperature (Tg) follows the eutectic profile of the liquidus temperature (Tm), coinciding with the melting zone in cement production. The viscosity has been uniquely charted over 14 decades for each calcium-aluminate phase, projecting and justifying the different temperature zones used in cement manufacture. The fragile–strong phase transitions are revealed across all supercooled phases coinciding with heterogeneous nucleation close to 1.2Tg, where sintering and quenching occur in industrial-scale cement processing.
KW - aerodynamic levitation
KW - calcium aluminates
KW - cement
KW - fragile–strong phase transitions
KW - molecular dynamic simulation
UR - http://www.scopus.com/inward/record.url?scp=85075723833&partnerID=8YFLogxK
U2 - 10.1002/advs.201902209
DO - 10.1002/advs.201902209
M3 - Journal article
SN - 2198-3844
VL - 7
JO - Advanced Science
JF - Advanced Science
IS - 2
M1 - 1902209
ER -