Thermodynamic study of the NaPO3-Na3PO4 system : activity measurements in melts of NaPO3-Na3PO4-SiO2 system at 1673 K by differential mass spectrometry spectrometry

• Type: Article in International Scientific Journal
• Date: 1994

Authors

L. F. Malheiros (Author) FEUP; C. Chatillon (Author) Other; M. Allibert (Author) Other

Journal

Title: Revue Internationale des Hautes Temperatures et des Refractaires

Vol. 29

Pages: 89-99

ISSN: 0035-3434

Indexing

ISI Web of Science

Other information

Resumo (PT): Activities of Na2O and P2O5; in the molar fraction range XNa2O = 0.5 to 0.75 of the P205-Na2O system have been determined using high temperature mass spectrometry in conjunction with a multiple Knudsen cell device. Measurements are presented as a function of the different vaporisation equilibria occurring in this system according to the composition Physico-chemical difficulties encountered during these experiments are exposed as creeping and wall porosity which were either avoided or prevented in order to reach the necessary stability of the effusion process Thermodynamic cross-checks are performed using Gibbs energy of formation of the phosphates, Gibbs-Duhem integration, partial congruent vaporisation in the quasi-binary phosphates section as well as the detection limits of the mass spectrometer in order to do a selection of reliable experimental thermodynamic data for the liquid and solid phases.

Abstract (EN): Activities of Na2O and P2O5; in the molar fraction range XNa2O = 0.5 to 0.75 of the P205-Na2O system have been determined using high temperature mass spectrometry in conjunction with a multiple Knudsen cell device. Measurements are presented as a function of the different vaporisation equilibria occurring in this system according to the composition Physico-chemical difficulties encountered during these experiments are exposed as creeping and wall porosity which were either avoided or prevented in order to reach the necessary stability of the effusion process Thermodynamic cross-checks are performed using Gibbs energy of formation of the phosphates, Gibbs-Duhem integration, partial congruent vaporisation in the quasi-binary phosphates section as well as the detection limits of the mass spectrometer in order to do a selection of reliable experimental thermodynamic data for the liquid and solid phases.

Language: Portuguese

Type (Professor's evaluation): Scientific