Dissolution of zirconium in nitric-hydrofluoric acid mixtures
- National Inst. of Standards and Technology, Gaithersburg, MD (United States)
There is a linear relationship between the enthalpy of solution of zirconium in nitric-hydrofluoric acid (HNO{sub 3}-HF) mixtures and the molar HNO{sub 3}/HF ratio (R) from R = 0 to 0.55. At R = 0.55, the enthalpy attains a maximum value and remains constant up to at least R = 8. There is a corresponding behavior in a reverse order with regard to hydrogen evolution, which is linear with R from a maximum at R = 0 to zero at R {ge} 0.55. Regardless of composition of the mixed acids, the zirconium-containing product is the same. A mechanism was proposed to account for the relationship of solution enthalpy and hydrogen evolution with the acid ratio. The rate of dissolution of zirconium in HF alone displayed a strong dependence on concentration > 0.5 mol/L. It was not sensitive to addition of HNO{sub 3}, but there was a slowing of the rate for HNO{sub 3} concentrations > 0.4 mol/L.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 477476
- Journal Information:
- Corrosion, Journal Name: Corrosion Journal Issue: 4 Vol. 53; ISSN 0010-9312; ISSN CORRAK
- Country of Publication:
- United States
- Language:
- English
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