THERMODYNAMIC PROPERTIES OF Sb_2O_3-SiO_2 AND PbO-Sb_2O_3-SiO_2 LIQUID SOLUTIONS

摘要

Thermodynamic properties of the liquid PbO-SiO_2 and Sb_2O_3-SiO_2 solutions were derived from the results of the electrochemical studies by the use of solid oxide galvanic cells with YSZ electrolyte. Activities of PbO in silicate melts were determined directly in the temperature range from 850 to 1025 K and for SiO_2 mole fractions 0.2, 0.3, 0.4 and 0.5 from measured e.m.f.'s of the cell: Pb, PbO - SiO_2 | YSZ | Ni, NiO relatively to Gibbs energy change of pure PbO formation. The thermodynamic properties of Sb_2O_3-SiO_2liquid solutions were derived indirectly from the measurements conducted with the cell of the type: Pb, PbO - Sb_2O_3 - SiO_2 | YSZ | Ni, NiO in ternary Pb0-Sb_2O_3-SiO_2 liquid solutions in the temperature range from 1070 to 1280 K. Two pseudobinary phase diagrams, namely, PbO-SiO_2 and PbO-Sb_2O_3 were optimized, and next using the obtained results the diagram of Sb_2O_3-SiO_2 system, and the liquidus in the pseudoternary Pb0-Sb_2O_3-SiO_2 were predicted.