Thermochemistry and phase equilibria in calcium zeolites

Abstract

Other| June 01, 1996 Thermochemistry and phase equilibria in calcium zeolites Irina Kiseleva; Irina Kiseleva Princeton University, Department of Geological and Geophysical Sciences, Princeton, NJ, United States Search for other works by this author on: GSW Google Scholar Alexandra Navrotsky; Alexandra Navrotsky Search for other works by this author on: GSW Google Scholar Igor A. Belitsky; Igor A. Belitsky Search for other works by this author on: GSW Google Scholar Boris A. Fursenko Boris A. Fursenko Search for other works by this author on: GSW Google Scholar American Mineralogist (1996) 81 (5-6): 658–667. https://doi.org/10.2138/am-1996-5-613 Article history first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Irina Kiseleva, Alexandra Navrotsky, Igor A. Belitsky, Boris A. Fursenko; Thermochemistry and phase equilibria in calcium zeolites. American Mineralogist 1996;; 81 (5-6): 658–667. doi: https://doi.org/10.2138/am-1996-5-613 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Thermodynamic properties of the natural calcium zeolites laumontite, leonhardite, dehydrated leonhardite (metaleonhardite), wairakite, and yugawaralite were studied by calorimetry in lead borate solvent at 975 K. Enthalpies of formation from the elements at 298 K are as follows: −7251.0 ± 8.5 kj/mol for laumontite, CaAl2Si4O12-4H2O; −7107.3 ± 5.6 kj/mol for leonhardite, CaAl2Si4O12 · 3.5H2O; −5964.3 ± 5.1 kj/mol for metaleonhardite, CaAl2Si4O12; −6646.7 ± 6.3 kj/mol for wairakite, CaAl2Si4O12-2H2O; and −9051.3 ± 10.4 kj/mol for yugawaralite, CaAl2Si6O16 · 4H2O. The value for leonhardite is in good agreement with early values from acid calorimetry (Barany 1961) but not with revised values from Hemingway and Robie (1977). The enthalpy of dehydration of leonhardite is 140.2 ±6.7 kj/mol, and the loss of one mole of H2O is associated with an endothermic effect of about 40 kI. Standard entropies, 5%, of wairakite [400.7 J/(molK)] and yugawaralite [609.8 J/(molK)] were derived from our new enthalpy data combined with reversed P-T phase equilibria (Liou 1971; Zeng and Liou 1982). The upper limit of wairakite stability, the univariant curve for equilibrium of wairakite with anorthite, quartz, and fluid, was calculated from these values of enthalpy and entropy. Good agreement between thermodynamic calculations and reversed phase equilibria supports the reliability of the new thermodynamic data. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.