VAPORIZATION BEHAVIOR AND MEASUREMENT OF DIFFUSION COEFFICIENTS OF FLUORIDES VAPORIZED FROM VARIOUS MOLTEN SLAGS

不同熔渣汽化氟化物的汽化行为及扩散系数的测量

• 批准号: 13650793
• 负责人: KASHIWAYA Yoshiaki
• 金额: $ 2.43万
• 依托单位: HOKKAIDO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650793/
• 关键词: diffusion coefficient; fluoride vaporization; Molten slag; SiF4; NaF; Na2SiF6

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.

高温过程中自发氟化物的排放会导致大气中氟含量增加和环境污染。含有SiO_2、Na_2O和CaF_2的炉渣在高温下往往不稳定，同时会析出NaF和SiF_4等气态物质。此外，NaF与SiF_4之间可以发生反应生成Na_2SiF_6（六氟硅酸钠），其行为和性质尚未明确。测量了NaF在氩气、氮气和氦气中的扩散系数。此外,考察了NaF在SiF_4-Ar气氛中的蒸发速率,测量了Na_2SiF_6的生成和解离速率。进行了动力学分析,得到了Na_2SiF_6的生成和解离速率常数。

项目成果

Y.Kashiwaya: "Kinetics of formation and dissociation of Na_2SiF_6"Metallurgical and Materials Transactions B. 33B. 129-136 (2002)

Y.Kashiwaya：“Na_2SiF_6 形成和解离的动力学”Metallurgical and Materials Transactions B. 33B。