Aqueous solubility of magnesian calcites with different endmembers
The aqueous solubility of magnesian calcites has been studied on the basis of the total solubility product (LlPPMANN, 1980) for magnesite, dolomite, and huntite as possible endmembers. Deviations from ideal solid solubility were estimated in terms of excess lattice energies calculated from interioni...
Elmentve itt :
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| Dokumentumtípus: | Cikk |
| Megjelent: |
University of Szeged, Department of Mineralogy, Geochemistry and Petrology
Szeged
1991
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| Sorozat: | Acta mineralogica-petrographica
32 |
| Kulcsszavak: | Kőzettan, Ásványtan, Földtan |
| Tárgyszavak: | |
| Online Access: | http://acta.bibl.u-szeged.hu/24788 |
| Tartalmi kivonat: | The aqueous solubility of magnesian calcites has been studied on the basis of the total solubility product (LlPPMANN, 1980) for magnesite, dolomite, and huntite as possible endmembers. Deviations from ideal solid solubility were estimated in terms of excess lattice energies calculated from interionic distances for magnesite and huntite. In the case of the dolomite endmember, a value obtained by extrapolation of experimental high-temperature data could be used to describe deviations from ideal behaviour. Solid solubility is limited, at 25 °C, by the spinodal points which were calculated for the endmembers magnesite, dolomite, and huntite to amount to 6, 3, and 18.3 mole percent Mg, respectively. Accordingly, huntite is the endmember that accounts for the full range of compositions observed in low-temperature magnesian calcites. For the endmembers dolomite and huntite, new formulae are presented, that express the total solubility product as the sum of partial solubility products and as functions of solid and aqueous compositions in the system CaCC>3—MgC03. The resulting phase diagrams depicting the aqueous solubility of magnesian calcites may serve as guidelines in experiments where such mixed crystals are to be equilibrated with suitably composed aqueous solutions. |
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| Terjedelem/Fizikai jellemzők: | 5-19 |
| ISSN: | 0365-8066 |