Melting Phenomena in the System CaO–SiO2– H2O: I, The Join Ca2SiO,-Ca(OH)2 |
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| Authors: | R I HARKER D M ROY O F TUTTLE |
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| Affiliation: | Johns-Manville Research Center, Manville, New Jersey, and Department of Geophysics and Geochemistry, The Pennsylvania State University, University Park, Pennsylvania |
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| Abstract: | The liquidus-solidus relations along the join Ca2SiO4-Ca(OH), in the system CaO-SiO2-H2O have been determined at 1000 atm up to 1110°C. This join is binary and contains the calcium silicate hydrate, calciochondrodite, Ca5-(SiO4(OH)2. Calciochondrodite melts incongruently to Ca2SiO2+ liquid (composition 23 wt% Ca2Si04) at 955°C. The eutectic between calcium hydroxide and calciochondrodite lies at 13% Ca2Si04 and 822°C. Preliminary experiments, also at 1000 atm, in the ternary system CaO-Ca2Si04-Ca(OH), indicate that the eutectic at which the fields of primary Ca(OH)2, CaO, and Ca2(Si04)2(OH)2 meet is close to the CaO-Ca. (OH), side of the triangle at approximately 805° C. The ternary reaction point Ca2SiOl+ liquid ?Ca5(SiO4)2(OH)2+ CaO + liquid is believed to lie in the low-CaO (<5%) high-Ca(OH)2 (>70%) part of the system. |
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