Link to document:
Status
Electronic Resource
Call number
Publication
SAND Report: SAND80-8040, November 1980.
Collection
Language
Library's review
ABSTRACT:
The thermophysical properties (viscosity, surface tension, and density) of the molten equimolar mixture NaN03-KN03 have been determined over the temperature range 300-600°C in argon and in oxygen. The surface tension is a linear function of the temperature and can be represented by the
y(dynes/cm) = 133.12 - 6.25 x 10-2T(OC) •
The viscosity may be calculated from the equation
n(cP) = 22.714 - 0.120T + 2.281 x 10-4T2 - 1.474 x 10-7T3 ,
for T in °c, with an uncertainty of 1.0%. The viscosity can be characterized by two activation energies •. For temperatures below 385°C, En = 4.5 kcal/mole; above 385°C, En = 3.2 kcal/mole, in argon and in oxygen. This suggests that at temperatures below 385°C free rotation of the nitrate ion becomes restricted, with a consequent increase in the activation energy for viscous flow. In argon the density is given by
p(g/cm3) = 2.090 - 6.36 x 10-4T(OC) •
However, if the melt is held at 600°C, for extended periods the density begins to decrease slowly due to formations of nitrite. After 72 hours at 600°C the density is given by
p(g/cm3) = 2.062 - 6.11 x 10-4T(OC) •
The thermophysical properties (viscosity, surface tension, and density) of the molten equimolar mixture NaN03-KN03 have been determined over the temperature range 300-600°C in argon and in oxygen. The surface tension is a linear function of the temperature and can be represented by the
Show More
expressiony(dynes/cm) = 133.12 - 6.25 x 10-2T(OC) •
The viscosity may be calculated from the equation
n(cP) = 22.714 - 0.120T + 2.281 x 10-4T2 - 1.474 x 10-7T3 ,
for T in °c, with an uncertainty of 1.0%. The viscosity can be characterized by two activation energies •. For temperatures below 385°C, En = 4.5 kcal/mole; above 385°C, En = 3.2 kcal/mole, in argon and in oxygen. This suggests that at temperatures below 385°C free rotation of the nitrate ion becomes restricted, with a consequent increase in the activation energy for viscous flow. In argon the density is given by
p(g/cm3) = 2.090 - 6.36 x 10-4T(OC) •
However, if the melt is held at 600°C, for extended periods the density begins to decrease slowly due to formations of nitrite. After 72 hours at 600°C the density is given by
p(g/cm3) = 2.062 - 6.11 x 10-4T(OC) •
Show Less