From Molten Calcium Aluminates through Phase Transitions to Cement Phases

Authors Organisations
  • Hao Liu(Author)
    Wuhan University of Technology
    Aalborg University
  • Wenlin Chen(Author)
  • Ruikun Pan(Author)
    Wuhan University of Technology
    Hubei University
  • Zhitao Shan(Author)
    Wuhan University of Technology
  • Ang Qiao(Author)
    Wuhan University of Technology
    Aalborg University
  • James W. E. Drewitt(Author)
    University of Bristol
  • Louis Hennet(Author)
    University of Orléans
  • Sandro Jahn(Author)
    University of Cologne
  • Dave Langstaff(Author)
  • Gregory A. Chass(Author)
    Queen Mary University of London
    University of Hong Kong
    McMaster University
    Sapienza University of Rome
  • Haizheng Tao(Author)
    Wuhan University of Technology
  • Yuanzheng Yue(Author)
    Wuhan University of Technology
    Aalborg University
    Qilu University of Technology
  • Neville Greaves(Author)
Type Article
Original languageEnglish
Article number1902209
JournalAdvanced Science
Early online date26 Nov 2019
DOI
Publication statusE-pub ahead of print - 26 Nov 2019
Show download statistics
View graph of relations
Citation formats

Abstract

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 we report the first in situ measurements of viscosity and density across all the principal molten phases, relevant to their eventual crystalline structures. Bulk atomistic computer simulations confirm that thermo-physical properties scale with the evolution of network substructures interpenetrating melts on the nanoscale. We have demonstrated that the glass transition temperature (Tg) follows the eutectic profile of the liquidus temperature (Tm), coinciding with the melting zone in cement production. We have uniquely charted the viscosity over 14 decades for each calcium aluminate phase, projecting and justifying the different temperature zones used in cement manufacture. We have revealed the fragile-strong phase transitions across all supercooled phases coinciding with heterogeneous nucleation close to 1.2Tg, where sintering and quenching occur in industrial-scale cement processing.

Keywords

  • Calcium Aluminates, Aerodynamic Levitation, Molecular Dynamic Simulation, Supercooled Liquids, Fragile-Strong Phase Transitions.