Home A thermodynamic model for silica and aluminum in alkaline solutions with high ionic strength at elevated temperatures up to 100 °C: Applications to zeolites
Article
Licensed
Unlicensed Requires Authentication

A thermodynamic model for silica and aluminum in alkaline solutions with high ionic strength at elevated temperatures up to 100 °C: Applications to zeolites

  • Yongliang Xiong EMAIL logo
Published/Copyright: March 7, 2015
Become an author with De Gruyter Brill

Abstract

In this study, a thermodynamic model for silica and aluminum in high ionic strength solutions at elevated temperatures up to 100 °C is constructed. Pitzer equations are utilized for the thermodynamic model construction. This model is valid up to ionic strengths of ~24 molal (m) in NaOH solutions with silicate concentrations up to ~1.5 m. The speciation of silica (including monomers and polymers) and aluminum at elevated temperatures is taken into account. Also, the equilibrium constants for silicic acid and its polymer species (H4SiO4, H5Si2O7- , H4Si2O72-, and H5Si3O73-) at elevated temperatures up to 100 °C, are obtained based on theoretical calculations. Using this thermodynamic model, thermodynamic properties, including equilibrium constants, and respective reaction enthalpies are obtained for sodium silicates, zeolite A, and the amorphous form of zeolite A, based on solubility experiments at elevated temperatures. The equilibrium constants for zeolite A and amorphous precursor of zeolite A regarding the following reactions up to 100 °C,

where T is temperature in Kelvin. The enthalpy of formation from elements, Gibbs free energy of formation from elements, and standard entropy derived for zeolite A and the amorphous form of zeolite A with the chemical formulas mentioned above at 25 °C and 1 bar are -2738 ± 5 kJ/mol, -2541 ± 2 kJ/mol, 373 ± 10 J/(K·mol); and -2642 ± 3 kJ/mol, -2527 ± 2 kJ/mol, and 648 ± 10 J/(K·mol), respectively. The enthalpy of formation from elements for zeolite A derived in this study based on solubility experiments in hydrothermal solutions agrees well with those obtained by calorimetric measurements and by theoretical calculations.

Received: 2011-12-26
Accepted: 2012-8-23
Published Online: 2015-3-7
Published in Print: 2013-1-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. H/D isotope effects in brucite at low temperatures
  2. Coupled H and Nb, Cr, and V trace element behavior in synthetic rutile at 600 °C, 400 MPa and possible geological application
  3. Dissolution-reprecipitation vs. solid-state diffusion: Mechanism of mineral transformations in sylvanite, (AuAg)2Te4, under hydrothermal conditions
  4. Compression and structure of brucite to 31 GPa from synchrotron X-ray diffraction and infrared spectroscopy studies
  5. Full analysis of feldspar texture and crystal structure by combining X-ray and electron techniques
  6. Correlating planar microstructures in shocked zircon from the Vredefort Dome at multiple scales: Crystallographic modeling, external and internal imaging, and EBSD structural analysis
  7. A spectroscopic and carbon-isotope study of mixed-habit diamonds: Impurity characteristics and growth environment
  8. Thermal infrared and Raman microspectroscopy of moganite-bearing rocks
  9. Mineralogical characterization and formation of Fe-Si oxyhydroxide deposits from modern seafloor hydrothermal vents
  10. Cathodoluminescence properties of quartz eyes from porphyry-type deposits: Implications for the origin of quartz
  11. Microbeam X-ray analysis of Ce3+/Ce4+ in Ti-rich minerals: A case study with titanite (sphene) with implications for multivalent trace element substitution in minerals
  12. Aluminum ordering and clustering in Al-rich synthetic phlogopite: The influence of fluorine investigated by {19F/1H} 29Si CPMAS NMR spectroscopy
  13. DFT+U investigation of the catalytic properties of ferruginous clay
  14. A thermodynamic model for silica and aluminum in alkaline solutions with high ionic strength at elevated temperatures up to 100 °C: Applications to zeolites
  15. Nanopores in hematite (α-Fe2O3) nanocrystals observed by electron tomography
  16. Berthierine-like mineral formation and stability during the interaction of kaolinite with metallic iron at 90 °C under anoxic and oxic conditions
  17. An X-ray diffraction study of the pressure-induced hydration in cordierite at 4–5 GPa
  18. Natural occurrence of keatite precipitates in UHP clinopyroxene from the Kokchetav Massif: A TEM investigation
  19. High-pressure Raman spectroscopy, vibrational mode calculation, and heat capacity calculation of calcium ferrite-type MgAl2O4 and CaAl2O4
  20. First-principles study on the high-pressure phase transition and elasticity of KAlSi3O8 hollandite
  21. Zircon growth and recrystallization during progressive metamorphism, Barrovian zones, Scotland
  22. Saltonseaite, K3NaMn2+Cl6, the Mn analogue of rinneite from the Salton Sea, California
  23. Rongibbsite, Pb2(Si4Al)O11(OH), a new zeolitic aluminosilicate mineral with an interrupted framework from Maricopa County, Arizona, U.S.A.
  24. Quadratite, AgCdAsS3: Chemical composition, crystal structure, and OD character
  25. Crystal chemistry of layered Pb oxychloride minerals with PbO-related structures: Part I. Crystal structure of hereroite, [Pb32O20(O,⃞)](AsO4)2[(Si,As,V,Mo)O4]2Cl10
  26. Crystal chemistry of layered Pb oxychloride minerals with PbO-related structures: Part II. Crystal structure of vladkrivovichevite, [Pb32O18][Pb4Mn2O]Cl14(BO3)8·2H2O
  27. Amorphous materials: Properties, structure, and durability: Acceleration and inhibition effects of phosphate on phase transformation of amorphous calcium carbonate into vaterite
  28. Letter: Implications of equilibrium and disequilibrium among crystal phases in the Bishop Tuff
  29. Letter: Actinides in Geology, Energy, and the Environment: Chemistry and radiation effects of davidite
Downloaded on 16.9.2025 from https://www.degruyterbrill.com/document/doi/10.2138/am.2013.4089/html
Scroll to top button