Thermodynamics Research Center / ThermoML | International Journal of Thermophysics

Distillation Separation of Hydrofluoric Acid and Nitric Acid From Acid Waste using the Salt Effect on Vapor-Liquid Equilibrium

Yamamoto, H.[Hideki], Sumoge, I.[Iwao]
Int. J. Thermophys. 2011, 32, 3, 706-19
ABSTRACT
This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using apparatus made of PFE (perfluoroalkyl vinylether). Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 wt%). Acid mixture of nitric acid (5.0 mol/dm3) and hydrofluoric acid (5.0 mol/dm3) was prepared as sample solution for distillation test. The concentration of nitric acid in the first distillate decreased from 5.0 mol/dm3 to 1.13 mol/dm3, and the concentration of hydrofluoric acid increased to 5.41 mol/dm3. This first distillate was further distilled without addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol/dm3 and 0.46mol/dm3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.
Compounds
# Formula Name
1 HNO3 nitric acid
2 FH hydrogen fluoride
3 H2O water
4 KNO3 potassium nitrate
5 CsNO3 cesium nitrate
6 FK potassium fluoride
Datasets
The table above is generated from the ThermoML associated json file (link above). POMD and RXND refer to PureOrMixture and Reaction Datasets. The compound numbers are included in properties, variables, and phases, if specificied; the numbers refer to the table of compounds on the left.
Type Compound-# Property Variable Constraint Phase Method #Points
  • POMD
  • 1
  • 3
  • Mole fraction - 1 ; Gas
  • Mole fraction - 1; Liquid
  • Pressure, kPa; Gas
  • Gas
  • Liquid
  • Titration method
  • 5
  • POMD
  • 1
  • 3
  • Boiling temperature at pressure P, K ; Liquid
  • Mole fraction - 1; Liquid
  • Pressure, kPa; Gas
  • Liquid
  • Gas
  • Ebulliometric method (Recirculating still)
  • 5
  • POMD
  • 1
  • 3
  • 5
  • Boiling temperature at pressure P, K ; Liquid
  • Mole fraction - 1; Liquid
  • Mass fraction - 5; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Gas
  • Ebulliometric method (Recirculating still)
  • 8
  • POMD
  • 1
  • 3
  • 5
  • Mole fraction - 1 ; Gas
  • Mole fraction - 1; Liquid
  • Mass fraction - 5; Liquid
  • Pressure, kPa; Gas
  • Gas
  • Liquid
  • Titration method
  • 8
  • POMD
  • 1
  • 3
  • 4
  • Boiling temperature at pressure P, K ; Liquid
  • Mole fraction - 1; Liquid
  • Mass fraction - 4; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Gas
  • Ebulliometric method (Recirculating still)
  • 6
  • POMD
  • 1
  • 3
  • 4
  • Mole fraction - 1 ; Gas
  • Mole fraction - 1; Liquid
  • Mass fraction - 4; Liquid
  • Pressure, kPa; Gas
  • Gas
  • Liquid
  • Titration method
  • 6
  • POMD
  • 2
  • 3
  • Mole fraction - 2 ; Gas
  • Mole fraction - 2; Liquid
  • Pressure, kPa; Gas
  • Gas
  • Liquid
  • Titration method
  • 5
  • POMD
  • 2
  • 3
  • Boiling temperature at pressure P, K ; Liquid
  • Mole fraction - 2; Liquid
  • Pressure, kPa; Gas
  • Liquid
  • Gas
  • Ebulliometric method (Recirculating still)
  • 5
  • POMD
  • 2
  • 3
  • 6
  • Boiling temperature at pressure P, K ; Liquid
  • Mole fraction - 2; Liquid
  • Mass fraction - 6; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Gas
  • Ebulliometric method (Recirculating still)
  • 5
  • POMD
  • 2
  • 3
  • 6
  • Mole fraction - 2 ; Gas
  • Mole fraction - 2; Liquid
  • Pressure, kPa; Gas
  • Mass fraction - 6; Liquid
  • Gas
  • Liquid
  • Titration method
  • 5
  • POMD
  • 2
  • 3
  • 5
  • Boiling temperature at pressure P, K ; Liquid
  • Mole fraction - 2; Liquid
  • Mass fraction - 5; Liquid
  • Pressure, kPa; Liquid
  • Liquid
  • Gas
  • Ebulliometric method (Recirculating still)
  • 3
  • POMD
  • 2
  • 3
  • 5
  • Mole fraction - 2 ; Gas
  • Mole fraction - 2; Liquid
  • Pressure, kPa; Gas
  • Mass fraction - 5; Liquid
  • Gas
  • Liquid
  • Titration method
  • 3