Fundamental theories and concepts for predicting thermodynamic properties of high temperature ionic and metallic liquid
- PDF / 116,139 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 29 Downloads / 192 Views
I. INTRODUCTION
CONCEPTS and theories for high-temperature solutions of molten salts, silicates, and metals, developed in the last 50 years, enable one to accurately predict the thermodynamic properties of multicomponent solutions from those of the generally well-known binary and sometimes ternary systems. Because of the occasion, this article will describe some of the history behind these developments. Before this period, there were a small number of notable theoretical concepts and revealing experiments. Salstrom and Hildebrand[1] published a series of articles on experimental electromotive force (emf) measurements starting in 1930. These demonstrated that liquid solutions of silver bromide with alkali bromides were “regular solutions,” a theoretical concept which was deduced for solutions with only nearestneighbor interactions. Such a remarkable result seemed strange for molten salts in which ionic interactions are longrange. The next landmark concept was deduced by Temkin,[2] who described a model for defining ideal solutions in molten salts with multiple types of cations and anions. His apparently simple result led to a revolutionary change in the description of complex ionic solutions, especially in metallurgical thermodynamics. Also worthy of note is a long series of articles which began to appear around 1928 by Bergman et al.[3] in Russia, who used a visual polythermal technique to measure the phase diagrams of hundreds of Dr. MILTON BLANDER is with Quest Research, South Holland, IL 60473-3114. He was a Group Leader and Senior Scientist at the Argonne National Laboratory until 1996 when he retired. This article is based on a presentation made at “The Milton Blander Symposium on Thermodynamic Predictions and Applications” at the TMS Annual Meeting in San Diego, California, on March 1–2, 1999, under the auspices of the TMS Extraction and Processing Division and the ASM Thermodynamics and Phase Equilibrium Committee. METALLURGICAL AND MATERIALS TRANSACTIONS B
ternary and higher-order systems. This massive database (supplemented by work in other Russian laboratories) revealed some of the unusual fundamental properties of reciprocal molten salt systems, which were used in the development of concepts and theories for these systems. The modern age for theories and concepts began in the 1950s in Norway, with pioneering articles such as those by Flood et al.[4] and Førland,[4] who examined concepts for reciprocal molten salt systems and mixtures of salts with cations of different charges. From these beginnings to today, a collection of concepts and theories has been developed which enables one to predict the thermodynamic properties of complex multicomponent solutions from generally wellknown subsidiary binary and ternary systems. (Concepts for metallic systems have been borrowed from theories of other liquids with ionic interactions or short-range interactions between the atoms.) This article will focus on simple examples of theories which have proven to be useful for technologies and science and which greatly mi
Data Loading...
