2002 Fiscal Year Final Research Report Summary
VAPORIZATION BEHAVIOR AND MEASUREMENT OF DIFFUSION COEFFICIENTS OF FLUORIDES VAPORIZED FROM VARIOUS MOLTEN SLAGS
| Project/Area Number |
13650793
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Metal making engineering
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KASHIWAYA Yoshiaki Hokkaido Univ. Grad. School of Eng., Asso. Prof., 大学院・工学研究科, 助教授 (10169435)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Yasushi Hokkaido Univ. Grad. School of Eng., Assi. Lec., 大学院・工学研究科, 助手 (90281782)
ISHII Kuniyoshi Hokkaido Univ. Grad. School of Eng., Prof., 大学院・工学研究科, 教授 (00001214)
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| Project Period (FY) |
2001 – 2002
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| Keywords | diffusion coefficient / fluoride vaporization / Molten slag / SiF4 / NaF / Na2SiF6 |
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| Research Abstract |
Spontaneous fluoride emission from high temperature processes can result in increased atmospheric fluorine contents and environmental contamination. Slags containing SiO_2, Na_2O and CaF_2 tend to be unstable at high temperatures and gaseous species such as NaF and SiF_4 evolve simultaneously. Furthermore, a reaction between NaF and SiF_4 can occur to produce Na_2SiF_6 (sodium hexafluorosilicate), whose behavior and properties are not well established.
The diffusivity of NaF in argon, nitrogen and helium was measured. Moreover, the rate of NaF vaporization in a SiF_4-Ar atmosphere was investigated and the rates of formation and dissociation of Na_2SiF_6 were measured.
Kinetic analyses were carried out and the rate constants of formation and dissociation of Na_2SiF_6 were obtained.
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