[Stability of CaF2 at high temperature].
In this paper, the stabilities of CaF2 in atmosphere, dry and moist air at elevated temperatures were studied by gaseous fluorides direct absorption and fluoride ion-selective electrode (ISE) measurements technique supplemented by differential thermal analysis (DTA), chemical analysis (pyrohydrolysis-ISE method) and X-ray diffraction (XRD) analysis. The principal reaction was shown to be hydrolysis of CaF2 at high temperature and CaF2 were actually hydrolyzed appreciably at about 830 +/- 10 degrees C in moist atmospheres. Kinetics calculation showed that hydrolysis reaction was first order and the activation energy for the hydrolysis was 115 +/- 2 kJ/mol, applicable over the range 850 degrees C-1350 degrees C. The research results will be of significance for fluoride pollution control during coal combustion and clay-brickmaking.
Qi
Qingjie
Q
Institute for Thermal Engineering, Zhejiang University, Hangzhou 310027, China. qiqj@cmee.zju.edu.cn
Liu
Jianzhong
J
Cao
Xinyu
X
Zhou
Junhu
J
Zhang
Shuxin
S
Kefa
Cen
C
D002124:Calcium Fluoride / Q000737:chemistry*; D006868:Hydrolysis; D013696:Temperature
D002124:Calcium Fluoride