title: [Stability of CaF2 at high temperature].
abstract: 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.
authors.affiliation: Institute for Thermal Engineering, Zhejiang University, Hangzhou 310027, China. qiqj@cmee.zju.edu.cn
authors.forename: Qingjie
authors.initials: Q
authors.lastname: Qi
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Liu
authors.forename: Xinyu
authors.initials: X
authors.lastname: Cao
authors.forename: Junhu
authors.initials: J
authors.lastname: Zhou
authors.forename: Shuxin
authors.initials: S
authors.lastname: Zhang
authors.forename: Cen
authors.initials: C
authors.lastname: Kefa
mesh_terms: D002124:Calcium Fluoride / Q000737:chemistry*; D006868:Hydrolysis; D013696:Temperature
chemical_list: D002124:Calcium Fluoride