High Temperature Decomposition of Almandine and Pyrope in Reducing Atmosphere
- Centre for Nanomaterial Research, Palacky University in Olomouc, 17. listopadu 1192/12, 771 46 Olomouc (Czech Republic)
Thermal decomposition of two garnets of near end-member composition--almandine (Fe{sub 2.85}Mg{sub 0.15})(Al{sub 1.99})Si{sub 2.99}O{sub 12} and pyrope (Mg{sub 2.22}Fe{sub 0.47}Ca{sub 0.33})(Cr{sub 0.11}Fe{sub 0.06}Al{sub 1.81})Si{sub 2.98}O{sub 12}--has been carried out in reducing atmosphere (forming gas: 10% of H{sub 2} in N{sub 2}). High-temperature behavior of both samples was monitored using simultaneous thermogravimetry and differential scanning calorimetry. The decomposition of almandine and pyrope turned out to proceed at slightly different temperatures above 1000 degree sign C. Therefore, two series of samples were prepared based on the results of thermal analysis: almandine heated up to 950 deg. C, 1070 deg. C and 1200 deg. C, and pyrope heated up to 1000 deg. C, 1100 deg. C, 1125 deg. C and 1200 deg. C. The identification of the decomposition products was performed by X-ray powder diffraction and Moessbauer spectroscopy. The common feature of the decomposition of both garnets is the presence of metallic iron and spinel phase, while the other products include fayalite, cristobalite, and cordierite for almandine; and enstatite and anorthite for pyrope. The formation of this last component was enabled due to Ca content in pyrope.
- OSTI ID:
- 21410582
- Journal Information:
- AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1258; ISSN APCPCS; ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Enthalpy of mixing synthetic almandine-grossular and almandine-pyrope garnets from high-temperature solution calorimetry
Solution properties of almandine-pyrope garnet as determined by phase equilibrium experiments
Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
ALUMINIUM ALLOYS
CALCIUM ALLOYS
CALORIMETRY
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
COHERENT SCATTERING
CRISTOBALITE
DECOMPOSITION
DIFFRACTION
ELEMENTS
ENSTATITE
GARNETS
GRAVIMETRIC ANALYSIS
HYDROGEN
IRON
IRON ALLOYS
MAGNESIUM ALLOYS
METALS
MINERALS
MOESSBAUER EFFECT
NONMETALS
OXIDE MINERALS
OXYGEN COMPOUNDS
PYROLYSIS
QUANTITATIVE CHEMICAL ANALYSIS
SCATTERING
SILICATE MINERALS
SILICON ALLOYS
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
THERMAL ANALYSIS
THERMAL GRAVIMETRIC ANALYSIS
THERMOCHEMICAL PROCESSES
TRANSITION ELEMENT ALLOYS
TRANSITION ELEMENTS
X-RAY DIFFRACTION