Molten Salt Theory and Application

Author: Xie Gang
Editor-in-Chief: Tan Xueyu
Publisher:
Publishing Date: 1998-08-01
Features:
Content Summary
This book systematically elaborates on the fundamental theories of molten salts and their applications in various fields. The content includes the theory of molten salt structure, the physicochemical properties of molten salts, molten salt mixtures, computer simulations of molten salts, molten salt electrolysis, molten salt batteries, the application of molten salts in the nuclear industry, molten salt electroplating, and more. It combines theory with application, providing a comprehensive overview of the latest research achievements in molten salts both domestically and internationally. This book is suitable for scientific and technical personnel engaged in theoretical and applied research on molten salts, as well as engineers in industries such as chemical plants, smelting plants, and electroplating plants. It can also serve as a teaching reference for relevant majors in colleges and universities.
Excerpt:
1 Introduction
1.1 Introduction
Molten salts are the molten state of salts, typically referring to the molten state of inorganic salts. Inorganic salts that form a molten state mostly exist as ionic crystals in their solid form, and when melted at high temperatures, they form ionic melts. Therefore, the most common molten salts are composed of alkali metals or alkaline earth metals combined with halides, silicates, carbonates, nitrates, and phosphates. Table 1-1 lists the main elements constituting molten salts.
Molten salts possess numerous properties distinct from aqueous solutions, such as high-temperature stability, low vapor pressure over a wide range, low viscosity, good electrical conductivity, high ionic mobility and diffusion rates, high heat capacity, and the ability to dissolve various materials. These properties determine the broad industrial applications of molten salts, primarily including:
(1) As electrolytes for metal extraction. The earliest application of molten salts was in metal electrolysis, and to this day, the production of metals such as aluminum and the extraction of rare earth metals still primarily rely on molten salt electrolysis methods. Other metals like alkali metals, alkaline earth metals, and high-melting-point metals are also produced using molten salt electrolysis. Producing metals with molten salt electrolysis offers advantages such as a simple process flow, high metal recovery rates, high product quality, and high levels of mechanization and automation. Currently, molten salt electrolysis is the sole industrial method for producing aluminum, and it is unlikely to be replaced by other methods in the near future.
(2) Applications in the nuclear industry. In homogeneous reactors, the use of molten salt mixtures as fuel solvents and heat transfer media offers numerous advantages, including variable operating temperatures, easy fuel addition, and the continuous removal of fission products. The most widely used molten salt system in the nuclear industry is the LiF-BeF? system.