Investigations of the high-T behavior of CaO in the CaO-SiO2 and CaO-Y2O3 systems with aerodynamically levitated laser heating and drop-and-catch calorimetry
Abstract
CaO is an important component of geologic systems, as well as being the primary constituent of cement and an important fluxing agent in metallurgy. Despite its importance, there remains a great deal of uncertainty in liquidus temperatures of CaO-rich parts of CaO-SiO2 and CaO-Y2O3 systems. We will present new data on the liquidus temperatures of Ca2SiO4, Ca3SiO5, and CaO90-(Y2O3)10 and CaO80-(Y2O3)20. These data are collected at UC Davis from thermal arrests on crystallization of spheroids approx. 2mm diameter, levitated in argon. Samples are melted with a 400W CO2 laser, then the laser is turned off and temperature profiles on cooling are recorded with a spectropyrometer (FAR Associates, Macedonia, OH). In addition, we will present data on the enthalpy of fusion of Ca2SiO4, collected with the new "drop and catch" calorimeter that has been designed and calibrated at UC Davis. This instrument enables measurements of heats of fusion by drop calorimetry of small (100 mg or less) samples which are aerodynamically levitated, negating the need for a container. Samples are laser heated while levitated in argon with a splittable nozzle levitator to the required temperature, which is monitored with a spectropyrometer. The sample is then dropped by splitting the nozzle, and subsequently caught by water-cooled calorimetric plates at 25°C. This work was supported by NSF DMR-1835848
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMMR23D0135A
- Keywords:
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- 3919 Equations of state;
- MINERAL PHYSICS;
- 3924 High-pressure behavior;
- MINERAL PHYSICS;
- 3939 Physical thermodynamics;
- MINERAL PHYSICS;
- 3994 Instruments and techniques;
- MINERAL PHYSICS