ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Cryometric analysis of the phase-diagrams of pseudobinary systems of the system CaO.SiO₂(CS)-2CaO.Al₂O_3.SiO₂(C₂AS)-CaO.Al₂O_3.2SiO₂ (CAS₂). 1. Theoretical part

I. Proks, M. Eliášová, and O. Žigo

Institute of Inorganic Chemistry, Slovak Academy of Sciences, CS-842 36 Bratislava

Abstract: Applicability of cryometric analysis of phase diagrams of binary silicate systems (the systems having peritectic melting are not included) for determination of structure of molten silicates is discussed. The method is based on application of the Le Chatelier-Shreder equation in the region of infinite dilution of one component (admixture A) in the second component (solvent S). Knowledge of experimental values of enthalpy of fusion of pure components S and of experimentally determined courses of liquidus (and solidus) curves in a binary system is required. Result of the analysis is determination of the mean value of the sum of number of moles of all products ∑_i¹- v(P_i(A))_l which are formed when 1 mol of "formula" admixture A is dissolved in an infinite amount of solvent S and an infinitely diluted solution L(A in S) is formed.Main errors sources of this method are: error in determination of the enthalpy of fusion of S; incorrect or not sufficiently precise determination of liquidus or solidus curves in the phase diagram, which gives a wrong value of the limit dT/d(w(A))_l and dT/d(w(A))_s at infinite dilution; the method is unable to distinguish among the products P_i(A) which a) form in the liquid and solid phases solutions having similar composition, b) are identical with the products of dissociation of solvent S.

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Chemical Papers 46 (1) 7–9 (1992)