D. Heuser, E. Petrishcheva, F. Ingegneri, C. L. Lengauer, E. Dachs, C. Hauzenberger, R. Abart
{"title":"从 Na-K 分配法和低温量热法看无序碱长石固溶体的热力学混合特性","authors":"D. Heuser, E. Petrishcheva, F. Ingegneri, C. L. Lengauer, E. Dachs, C. Hauzenberger, R. Abart","doi":"10.1007/s00269-024-01270-z","DOIUrl":null,"url":null,"abstract":"<div><p>The equilibrium partitioning of Na and K between alkali feldspar and NaCl–KCl salt melt was determined at 800 <span>\\(^\\circ\\)</span>C, 850 <span>\\(^\\circ\\)</span>C, 900 <span>\\(^\\circ\\)</span>C, 950 <span>\\(^\\circ\\)</span>C and 1000 <span>\\(^\\circ\\)</span>C and close to ambient pressure. Four different natural gem-quality alkali feldspars with low degree of Al–Si ordering covering the range from orthoclase to high sanidine and with slightly different minor element concentrations were used as starting materials. The partitioning curves obtained for the four feldspars are indistinguishable indicating that Na–K partitioning independent of the differences of Al–Si ordering state and minor element concentrations existing amongst these feldspars. A sub-regular two parameter Margules type solution model was fitted to the partitioning data, and the excess Gibbs energy describing the thermodynamic non-ideality of the alkali feldspar solid-solution and the respective Margules parameters <span>\\(W_{\\text {g}\\text {K}}\\)</span> and <span>\\(W_{\\text {g}\\text {Na}}\\)</span> including their temperature dependence expressed as <span>\\(W_g=W_h-TW_s\\)</span> were determined: </p><div><div><span>$$\\begin{aligned} W_{\\text {g}\\text {K}}&= 19754 \\pm 3140 J\\cdot \\,\\,{\\hbox {mol}}\\,\\,^{-1} - T \\cdot 2.33 \\pm 2.67 J\\cdot \\,\\,{\\hbox {mol}}\\,\\,^{-1}\\cdot K^{-1} \\\\ W_{\\text {g}\\text {Na}}&= 14916 \\pm 4272 J\\cdot \\,\\,{\\hbox {mol}}\\,\\,^{-1} - T \\cdot 3.55 \\pm 3.64 J\\cdot {\\hbox {mol}}\\,\\,^{-1}\\cdot K^{-1} \\\\ \\end{aligned}$$</span></div></div><p>The corresponding solvus has a critical temperature slightly above 650 <span>\\(^\\circ\\)</span>C and is well comparable with earlier direct experimental determinations of the low-sanidine-albite solvus curve. Comparison of the vibrational excess entropy determined from low-temperature heat capacity measurements with the total excess entropy derived from the temperature dependence of the excess Gibbs energy yields a negative configurational contribution to the excess entropy pointing towards short-range Na–K ordering on the alkali site.</p></div>","PeriodicalId":20132,"journal":{"name":"Physics and Chemistry of Minerals","volume":null,"pages":null},"PeriodicalIF":1.2000,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00269-024-01270-z.pdf","citationCount":"0","resultStr":"{\"title\":\"Thermodynamic mixing properties of disordered alkali feldspar solid-solution from Na–K partitioning and low-temperature calorimetry\",\"authors\":\"D. Heuser, E. Petrishcheva, F. Ingegneri, C. L. Lengauer, E. Dachs, C. Hauzenberger, R. Abart\",\"doi\":\"10.1007/s00269-024-01270-z\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The equilibrium partitioning of Na and K between alkali feldspar and NaCl–KCl salt melt was determined at 800 <span>\\\\(^\\\\circ\\\\)</span>C, 850 <span>\\\\(^\\\\circ\\\\)</span>C, 900 <span>\\\\(^\\\\circ\\\\)</span>C, 950 <span>\\\\(^\\\\circ\\\\)</span>C and 1000 <span>\\\\(^\\\\circ\\\\)</span>C and close to ambient pressure. Four different natural gem-quality alkali feldspars with low degree of Al–Si ordering covering the range from orthoclase to high sanidine and with slightly different minor element concentrations were used as starting materials. The partitioning curves obtained for the four feldspars are indistinguishable indicating that Na–K partitioning independent of the differences of Al–Si ordering state and minor element concentrations existing amongst these feldspars. A sub-regular two parameter Margules type solution model was fitted to the partitioning data, and the excess Gibbs energy describing the thermodynamic non-ideality of the alkali feldspar solid-solution and the respective Margules parameters <span>\\\\(W_{\\\\text {g}\\\\text {K}}\\\\)</span> and <span>\\\\(W_{\\\\text {g}\\\\text {Na}}\\\\)</span> including their temperature dependence expressed as <span>\\\\(W_g=W_h-TW_s\\\\)</span> were determined: </p><div><div><span>$$\\\\begin{aligned} W_{\\\\text {g}\\\\text {K}}&= 19754 \\\\pm 3140 J\\\\cdot \\\\,\\\\,{\\\\hbox {mol}}\\\\,\\\\,^{-1} - T \\\\cdot 2.33 \\\\pm 2.67 J\\\\cdot \\\\,\\\\,{\\\\hbox {mol}}\\\\,\\\\,^{-1}\\\\cdot K^{-1} \\\\\\\\ W_{\\\\text {g}\\\\text {Na}}&= 14916 \\\\pm 4272 J\\\\cdot \\\\,\\\\,{\\\\hbox {mol}}\\\\,\\\\,^{-1} - T \\\\cdot 3.55 \\\\pm 3.64 J\\\\cdot {\\\\hbox {mol}}\\\\,\\\\,^{-1}\\\\cdot K^{-1} \\\\\\\\ \\\\end{aligned}$$</span></div></div><p>The corresponding solvus has a critical temperature slightly above 650 <span>\\\\(^\\\\circ\\\\)</span>C and is well comparable with earlier direct experimental determinations of the low-sanidine-albite solvus curve. Comparison of the vibrational excess entropy determined from low-temperature heat capacity measurements with the total excess entropy derived from the temperature dependence of the excess Gibbs energy yields a negative configurational contribution to the excess entropy pointing towards short-range Na–K ordering on the alkali site.</p></div>\",\"PeriodicalId\":20132,\"journal\":{\"name\":\"Physics and Chemistry of Minerals\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.2000,\"publicationDate\":\"2024-02-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://link.springer.com/content/pdf/10.1007/s00269-024-01270-z.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physics and Chemistry of Minerals\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s00269-024-01270-z\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physics and Chemistry of Minerals","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1007/s00269-024-01270-z","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
Thermodynamic mixing properties of disordered alkali feldspar solid-solution from Na–K partitioning and low-temperature calorimetry
The equilibrium partitioning of Na and K between alkali feldspar and NaCl–KCl salt melt was determined at 800 \(^\circ\)C, 850 \(^\circ\)C, 900 \(^\circ\)C, 950 \(^\circ\)C and 1000 \(^\circ\)C and close to ambient pressure. Four different natural gem-quality alkali feldspars with low degree of Al–Si ordering covering the range from orthoclase to high sanidine and with slightly different minor element concentrations were used as starting materials. The partitioning curves obtained for the four feldspars are indistinguishable indicating that Na–K partitioning independent of the differences of Al–Si ordering state and minor element concentrations existing amongst these feldspars. A sub-regular two parameter Margules type solution model was fitted to the partitioning data, and the excess Gibbs energy describing the thermodynamic non-ideality of the alkali feldspar solid-solution and the respective Margules parameters \(W_{\text {g}\text {K}}\) and \(W_{\text {g}\text {Na}}\) including their temperature dependence expressed as \(W_g=W_h-TW_s\) were determined:
The corresponding solvus has a critical temperature slightly above 650 \(^\circ\)C and is well comparable with earlier direct experimental determinations of the low-sanidine-albite solvus curve. Comparison of the vibrational excess entropy determined from low-temperature heat capacity measurements with the total excess entropy derived from the temperature dependence of the excess Gibbs energy yields a negative configurational contribution to the excess entropy pointing towards short-range Na–K ordering on the alkali site.
期刊介绍:
Physics and Chemistry of Minerals is an international journal devoted to publishing articles and short communications of physical or chemical studies on minerals or solids related to minerals. The aim of the journal is to support competent interdisciplinary work in mineralogy and physics or chemistry. Particular emphasis is placed on applications of modern techniques or new theories and models to interpret atomic structures and physical or chemical properties of minerals. Some subjects of interest are:
-Relationships between atomic structure and crystalline state (structures of various states, crystal energies, crystal growth, thermodynamic studies, phase transformations, solid solution, exsolution phenomena, etc.)
-General solid state spectroscopy (ultraviolet, visible, infrared, Raman, ESCA, luminescence, X-ray, electron paramagnetic resonance, nuclear magnetic resonance, gamma ray resonance, etc.)
-Experimental and theoretical analysis of chemical bonding in minerals (application of crystal field, molecular orbital, band theories, etc.)
-Physical properties (magnetic, mechanical, electric, optical, thermodynamic, etc.)
-Relations between thermal expansion, compressibility, elastic constants, and fundamental properties of atomic structure, particularly as applied to geophysical problems
-Electron microscopy in support of physical and chemical studies
-Computational methods in the study of the structure and properties of minerals
-Mineral surfaces (experimental methods, structure and properties)