Fluoride vaporization and crystallization of CaF2-CaO-Al2O3-(La2O3) slag for vacuum electroslag remelting

被引：4
作者：
Li, Tengfei [1 ]
Li, Guangqiang [1 ,2 ]
Zhang, Zhan [1 ]
Liu, Yu [1 ]
Wang, Xijie [3 ]
机构：
[1] Wuhan Univ Sci & Technol, State Key Lab Refractories & Met, Wuhan 430081, Hubei, Peoples R China
[2] Wuhan Univ Sci & Technol, Key Lab Ferrous Met & Resources Utilizat Minist E, Wuhan 430081, Hubei, Peoples R China
[3] Wuhan Univ Sci & Technol, Hubei Prov Key Lab New Proc Ironmaking & Steel Ma, Wuhan 430081, Peoples R China
来源：
VACUUM | 2022年 / 196卷
基金：
中国国家自然科学基金; 中国博士后科学基金;
关键词：
Fluoride vaporization; Crystallization; Slag; Electroslag remelting; La2O3; addition; VISCOSITY; BEHAVIOR;
D O I：
10.1016/j.vacuum.2021.110807
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
The vaporization and crystallization of CaF2-CaO-Al2O3 slags with different La2O3 contents for electroslag remelting were investigated by various analytical methods. The results show that the main volatiles from investigated slag within 7.4 wt% La2O3 content at 1723 K are CaF2 and AlF3. The weight loss of CaF2-CaO-Al2O3-(La2O3) slags decrease with increase of La2O3 content in both thermo gravimetric experiment and vacuum condition. The addition of La2O3 within 7.4 wt% reduces the viscosity and breaking temperature of investigated slag, and the change of viscosity is not the main reason to inhibit the fluoride vaporization. The vapor pressure of CaF2 and AlF3 at 1723 K decreases with increase of La2O3 content because of the changes in component activity. Thus, fluoride vaporization becomes weakened. The crystalline phases of CaF2-CaO-Al2O3 slag are 11CaO center dot 7Al(2)O(3)center dot CaF2 and CaF2, while the crystalline phases of slag within 7.4 wt% La2O3 content are (CaLa)Al3O7, La(AlO3) and CaF2. The La2O3 addition can decrease the crystallization temperature of CaF2 and prevent the precipitation of 11CaO center dot 7Al(2)O(3)center dot CaF2.
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页数：7
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