Component activities in the system thorium nitrate-nitric acid-water at 25/sup 0/C

Journal Article · Fri Jan 01 00:00:00 EST 1982 · J. Solution Chem.; (United States)

DOI:https://doi.org/10.1007/BF00667602· OSTI ID:5558108

Lemire, R J; Brown, C P

The equilibrium composition of the vapor above thorium nitrate-nitric acid-water mixtures has been studied as a function of the concentrations of thorium nitrate and nitric acid using a transpiration technique. At 25/sup 0/C, the thorium nitrate concentrations m/sub T/ ranged from 0.1 to 2.5 molal and the nitric acid concentrations m/sub N/ from 0.3 to 25 molal. The vapor pressure of the nitric acid was found to increase with increasing thorium nitrate concentration for a constant molatlity of nitric acid in aqueous solution. At constant m/sub T/, the nitric acid vapor pressure was particularly enhanced at low nitric acid concentrations. The water vapor pressures decreased regularly with increasing concentrations of both nitric acid and thorium nitrate. The experimental data were fitted to Scatchard's ion-component model, and to empirical multiparameter functions. From the fitting parameters, and available literature data for the nitric acid-water and thorium nitrate-water systems at 25/sup 0/C, expressions were calculated for the variation of water and thorium nitrate activities, as functions of the nitric acid and thorium nitrate concentrations, using the Gibbs-Duhem equation. Calculated values for the thorium nitrate activities were strongly dependent on the form of the function originally used to fit the vapor pressure data. 31 references, 6 figures, 4 tables.

• Research Organization: Whiteshell Nuclear Research Establishment, Pinawa, Manitoba
• OSTI ID: 5558108
• Journal Information: J. Solution Chem.; (United States), Vol. 11:3
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
NITRIC ACID
VAPOR PRESSURE
THORIUM NITRATES
REACTION KINETICS
THERMODYNAMIC ACTIVITY
AQUEOUS SOLUTIONS
EQUILIBRIUM
EXPERIMENTAL DATA
MEDIUM TEMPERATURE
MIXTURES
QUANTITY RATIO
WATER
ACTINIDE COMPOUNDS
DATA
DISPERSIONS
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
KINETICS
NITRATES
NITROGEN COMPOUNDS
NUMERICAL DATA
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SOLUTIONS
THERMODYNAMIC PROPERTIES
THORIUM COMPOUNDS
400702* - Radiochemistry & Nuclear Chemistry- Properties of Radioactive Materials