Kinetics of Excess Solute Precipitation in Liquid Sodium Solutions

摘要

The precipitation characteristics of excess silver and calcium solutes in their respective liquid sodium solutions were studied in the temperature range of 425 to 150C and the concentration range of approximately 20.0 to 0.10 weight-percent of solute. The excess solute was observed to precipitate out of the bulk of the respective solution as rapidly as the temperature was reduced. The data obtained best fit the empirical equation C0-CT/C0=(DT x Dt)K/d sq., where C0 is the initial solute saturation (number of atoms per gram of sodium) and CT is the concentration at any subsequent lower temperature. The quantity (C0-CT)/C0 is then the fraction of the total solute that precipitated out of solution; this excess was observed to be directly proportional to the product of the temperature decrement DT(dec. C) and corresponding elapsed cooling time Dt (min) and inversely proportional to the square of the interatomic solute distance d(cm). The factor K is a proportionality factor assumed to be nearly constant over the concentration and temperature range of the solutions investigated. (Author)