Thermodynamics of Molten Sulfate Mixtures

Autor: W. L. Worrell, A. K. Misra, D. P. Whittle
Rok vydání: 1982
Předmět:
Zdroj: Journal of The Electrochemical Society. 129:1840-1845
ISSN: 1945-7111
0013-4651
DOI: 10.1149/1.2124305
Popis: Quantitative studies of the formation of low melting point sulfates were made by equilibrating NiO-Na/sub 2/SO/sub 4/ mixtures with argon-SO/sub 2/-SO/sub 3/-air mixtures of different compositions in the temperature range 1000-1173 K. Using these data and the Na/sub 2/SO/sub 4/-NiSO/sub 4/ phase diagram, the enthalpy of fusion and melting temperature of NiSO/sub 4/ were estimated. An equation is given for the free energy change for the reaction NiO(s)+SO/sub 3/(g).NiSO/sub 4/(l) (dissolved in Na/sub 2/SO/sub 4/). This has then been used to calculate the minimum P/sub SO(3)/ required for liquid sulfate formation. Similar calculations were carried out from existing data for the CoSO/sub 4/-Na/sub 2/SO/sub 4/ system, and verified by a limited number of experiments. The calculated minimum P/sub SO(3)/ required for liquid sulfate formation is approximately an order of magnitude lower for Co-base alloys compared with Ni-base alloys, and the implications of this with regard to hot corrosion are briefly discussed. 16 refs.
Databáze: OpenAIRE