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Thermodynamic Analysis of Formation of Fluoride from Gangue in Bayan Obo Iron Concentrate Containing Fluorite |
Fang ZHANG1,2,Sheng-li AN1,2,Yi-ci WANG1,2,Guo-ping LUO1,Xiao-long SONG1 |
1. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing,Beijing 100083, Beijing, China 2. School of Materials and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, Inner Mongolia, China |
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Abstract In order to fill up the deficiency of the theoretical basis about fluoride formation during Bayan Obo iron concentrate roasting process, the thermodynamic conditions of the interactivity between the components of the gangue and calcium fluorite were studied by means of thermodynamic calculation, DTA-TG thermal analysis and XRD characterization. The results revealed that KF, NaF and SiF4 (gaseous) could be formed during the roasting process, and the tendency of the generation of KF is greater than that of NaF or SiF4 in standard state. Besides, the results of roasting experiments showed that the products of KCaCO3F and KCaF3 formed in the temperature range of 800-1250 �� and KF appears when the roasting temperature was higher than 1250 �� in K2O-CaF2 system. For the Na2O-CaF2 system, the product of NaF appears at temperature higher than 1050 ��. The formation reaction of gaseous SiF4 with solid phase CaO��SiO2 in SiO2-CaF2 system took place only at temperature higher than 1150 ��. In the natural potash feldspar-CaF2-CaO system, the fluorination reaction products involved KF at temperature higher than 1270 ��, while in the natural aegirine-CaF2-CaO system, NaF formed at temperature higher than 980 �� during roasting process.
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Received: 25 March 2014
Published: 06 March 2015
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Fund:Chinese National Natural Science Foundation |
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[1] |
Li-li YANG,,Hong-ming WANG,,Xiang ZHU,,Gui-rong LI,. Effect of Boron Mud and CaF2 on Surface Tension and Density of CaO-SiO2-B2O3 Ternary Slag Systems[J]. Chinese Journal of Iron and Steel, 2014, 21(8): 745-748. |
[2] |
WANG Hong-ming,YANG Li-li,LI Gui-rong,ZHU Xiang,ZHU Hua,,ZHAO Yu-tao. Effects of B2O3 and CaF2 on Melting Temperatures of CaO-SiO2-Fe2O3 System Fluxes[J]. Chinese Journal of Iron and Steel, 2013, 20(6): 21-24. |
[3] |
LUO Guo-ping,,WU Sheng-li,ZHANG Guang-jie,WANG Yi-ci,. Effects of Compound Silicate Gangue on Formation of Complex Calcium Ferrite During Sintering Process[J]. Chinese Journal of Iron and Steel, 2013, 20(3): 18-23. |
[4] |
ZHANG Zuo��tai,LI Jing,LIU Peng. Crystallization Behavior in Fluoride��Free Mold Fluxes Containing TiO2/ZrO2[J]. Chinese Journal of Iron and Steel, 2011, 18(5): 31-37. |
[5] |
JIANG Zhou��hua,DONG Yan��wu,LIANG Lian��ke,LI Zheng��bang. Hydrogen Pick��Up During Electroslag Remelting Process[J]. Chinese Journal of Iron and Steel, 2011, 18(4): 19-23. |
[6] |
LIU Li��xia;WANG Shi��jun;DONG Yuan��chi;JIA Xiao��hui. Performance of Low Fluoride Dephosphorization Slag of Hot Metal[J]. Chinese Journal of Iron and Steel, 2011, 18(1): 11-11. |
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