Activities and free energies of mixing in binary silicate melts

Activities of CoO in CoO–SiO2 melts were measured at 1450–1500 °C by equilibrating the melts, held in Pt–Rh containers, with atmospheres of known oxygen potential. Activities were calculated by the relationship[Formula: see text]where aCo, the activity of cobalt in the container, was determined in separate experiments.The results were compared with theoretical activity–composition curves based on the application of polymer theory to silicate melts. The results were in good agreement with theoretical curves calculated on the assumption of linear chains. In contrast, for all other binary silicate melts so far investigated the results are best represented in terms of theory in which all chain configurations are allowed. Ionic distributions and number average and weight average molecular weights were calculated as functions of the silica content from the experimental data. The calculated proportions of monomeric ion, SiO44−, dimer Si2O76−, and trimer Si3O108− were in reasonable agreement with experimental values based on trimethylsilylation and gas-chromatographic separation of the ionic constituents in quenched melts.

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Lux-Flood basicity of binary silicate melts

Journal of Physics and Chemistry of Solids ◽

10.1016/j.jpcs.2004.01.012 ◽

2004 ◽

Vol 65 (8-9) ◽

pp. 1609-1614 ◽

Cited By ~ 13

Author(s):

G. Ottonello ◽

R. Moretti

Keyword(s):

Silicate Melts ◽

Binary Silicate

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Activities and ionic distributions in liquid silicates: application of polymer theory

Canadian Journal of Chemistry ◽

10.1139/v70-238 ◽

1970 ◽

Vol 48 (9) ◽

pp. 1456-1464 ◽

Cited By ~ 95

Author(s):

C. R. Masson ◽

I. B. Smith ◽

S. G. Whiteway

Keyword(s):

Binary Systems ◽

Molecular Size ◽

Thermodynamic Activity ◽

Silicate Melts ◽

Size Distributions ◽

Chain Molecules ◽

Linear Chains ◽

High Silica ◽

The Mean ◽

Binary Silicate

Theoretical expressions derived previously for molecular size distributions in multichain polymers are applied to binary silicate melts. The treatment is an extension of a previous approach which was limited to the consideration of linear chains. When all configurations of the chain molecules are taken into consideration, the predicted variation of thermodynamic activity with composition agrees with experiment for all binary systems for which data are available. The effect of allowing for all chain configurations is largely to improve the fit between theory and experiment at high silica contents. Calculated ionic distributions for the system 'FeO'–SiO2 do not differ markedly from those previously reported. The mean chain length is unaffected. The results support previous views that principles of polymer chemistry can be applied usefully to silicate melts and glasses.

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Molecular size distributions in multichain polymers: application of polymer theory to silicate melts

Canadian Journal of Chemistry ◽

10.1139/v70-033 ◽

1970 ◽

Vol 48 (1) ◽

pp. 201-202 ◽

Cited By ~ 22

Author(s):

C. R. Masson ◽

I. B. Smith ◽

S. G. Whiteway

Keyword(s):

Entire Range ◽

Maximum Degree ◽

Molecular Size ◽

Degree Of Polymerization ◽

Branched Polymers ◽

Silicate Melts ◽

Size Distributions ◽

Polymer Theory ◽

Good Agreement ◽

Binary Silicate

Expressions developed previously by Flory and by the authors for molecular size distributions in branched polymers were used to derive theoretical curves of activity vs. composition in binary silicate melts. In contrast with curves based on the Flory distribution those derived from our result were in good agreement with experiment over the entire range of compositions up to the maximum degree of polymerization allowed by the theory. The comparison is illustrated for the systems PbO–SiO2 and SnO–SiO2.

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