High-temperature thermodynamic properties of chalcopyrite
| Autor: | B. R. Conard, J. S. Warner, R. Sridhar |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
Chemistry
Chalcopyrite Analytical chemistry chemistry.chemical_element Calorimetry engineering.material Copper Sulfur Atomic and Molecular Physics and Optics Standard enthalpy of formation Gibbs free energy symbols.namesake Crystallography visual_art symbols engineering visual_art.visual_art_medium General Materials Science Pyrite Physical and Theoretical Chemistry Solid solution |
| Zdroj: | The Journal of Chemical Thermodynamics. 12:817-833 |
| ISSN: | 0021-9614 |
| DOI: | 10.1016/0021-9614(80)90026-9 |
| Popis: | The enthalpies of natural and synthetic chalcopyrite (CuFeS2) were measured by drop calorimetry at temperatures from 397 to 830 K. The enthalpies of various phase asseblages having an overall composition equivalent to CuFeS2 were measured from 830 to 1400 K by the same method. The measured values of {Ho(T) − Ho(298.15 K)} and the derived values of Cpo and {So(T) − So(298.15 K)} for the natural chalcopyrite sample agree with previous results within 3 per cent between 500 and 1053 K and provide new information at higher temperatures. For both samples, three reactions were observed, in agreement with known phase relations in (copper + iron + sulfur). At 830 K chalcopyrite decomposed to an intermediate solid solution (iss) plus pyrite (py). At 930 K, the iss plus pyrite reacted to form iss plus elemental sulfur. At 1155 K homogeneous liquid formed. The specific enthalpies of these reactions were (52 ± 8), (11 ± 8), and (266 ± 12) J g−1, respectively. High-temperature enthalpies of formation and standard Gibbs free energies of formation for CuFeS2 up to 1500 K were calculated from the present results using ΔHfo(298.15 K) = −324 kJ mol−1, where the standard state of sulfur was S2(g), and So(298.15 K) = 124.98 J K−1 mol−1. |
| Databáze: | OpenAIRE |
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