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Rosén, Erik
Publications (2 of 2) Show all publications
Sandström, M. H., Boström, D. & Rosén, E. (2006). Determination of standard Gibbs free energy of formation for Ca2P2O7 and Ca(PO3)2 from solid state EMF measurements using yttria stabilised zirconia as solid electrolyte. Journal of Chemical Thermodynamics, 38(11), 1371-1376
Open this publication in new window or tab >>Determination of standard Gibbs free energy of formation for Ca2P2O7 and Ca(PO3)2 from solid state EMF measurements using yttria stabilised zirconia as solid electrolyte
2006 (English)In: Journal of Chemical Thermodynamics, ISSN 0021-9614, E-ISSN 1096-3626, Vol. 38, no 11, p. 1371-1376Article in journal (Refereed) Published
Abstract [en]

The equilibrium reactions: 3Ca2P2O7(s) + 6Ni(s) reversible arrow 2Ca3(PO4)2(s) + 2Ni3P(s) + 5/O-2(g) and 2Ca(PO3)2(s) + 6Ni(s) reversible arrow Ca2P2O7(s) + 2Ni3P(s) +/- 5/2O2(g) were studied in the temperature range 890 K to 1140 K. The oxygen equilibrium pressures were determined using galvanic cells incorporating yttria stabilized zirconia as solid electrolyte. From the measured data and using the literature values of standard Gibbs free energy of formation for Ca3(PO4)2 and Ni3P, the following relationship of the standard Gibbs free energy of formation for Ca2P2O7 and Ca(PO3)(2) were calculated:

ΔfG° (Ca2P2O7) +/- 11/(kJ · mol-1)=-3475.9 + 1.5441 (T/K) -0.1051 (T/K) · 1n(T/K) and

ΔfG° (Ca(PO3)2) +/- 12/(kJ · mol-1)= -3334.8 + 6.1561 (T/K) -0.6950(T/K) · 1n(T/K).

Keywords
EMF measurements, gibbs free energy of formation, solid electrolyte, uxiliary solid couple, calcium phosphates
Identifiers
urn:nbn:se:umu:diva-5285 (URN)10.1016/j.jct.2006.01.018 (DOI)000242435400016 ()
Available from: 2006-09-07 Created: 2006-09-07 Last updated: 2018-06-09Bibliographically approved
Råberg, M., Boström, D., Nordin, A., Rosén, E. & Warnqvist, B. (2003). Improvement of the binary phase diagram Na2CO3 -Na2S. Energy & Fuels, 17(6), 1591-1594
Open this publication in new window or tab >>Improvement of the binary phase diagram Na2CO3 -Na2S
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2003 (English)In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 17, no 6, p. 1591-1594Article in journal (Refereed) Published
Abstract [en]

Gasification of black liquor is an attractive alternative to the traditional recovery boiler. However, in process modeling of gasification, thermodynamic data for the key components are quite uncertain, which will reduce the reliability of the modeling of the chemical processes in a gasifier. The objective of this work was to experimentally re-determine and improve data on the binary phase diagram Na2CO3−Na2S, especially on the Na2CO3 side of the system, which is the region of interest concerning black liquor combustion and gasification, and also the region with the most significant uncertainties. Measurements were carried out in a dry inert atmosphere at temperatures from 25 to 1200 °C, using high-temperature microscopy (HTM) and high-temperature X-ray powder diffraction (HT-XRD). To examine the influence of pure CO2 atmosphere on the melting behavior, HTM experiments in the same temperature interval were made. This paper presents new data complementary to earlier published data on the binary phase diagram Na2CO3−Na2S. These include re-determination of liquidus curves, in the Na2CO3-rich area, melting points of the pure components, as well as determination of the extent of the solid solution, Na2CO3(ss), area.

Place, publisher, year, edition, pages
American Chemistry Society, 2003
Identifiers
urn:nbn:se:umu:diva-2408 (URN)10.1021/ef0340256 (DOI)
Available from: 2007-05-16 Created: 2007-05-16 Last updated: 2018-06-09Bibliographically approved
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