Kinetics of Al 2 O 3 dissolution in CaO-MgO-SiO 2 -Al 2 O 3 slags: In Situ observations and analysis
- PDF / 751,189 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 42 Downloads / 237 Views
6prh
[2]
where h is the liquid viscosity. However, as no data are available on viscosities in the system under humid conditions, this explanation must be regarded as tentative. The measurement of crystallization in humid atmospheres at temperatures above the liquidus temperature suggests that the liquidus temperature in this system is a function of humidity. The reversible nature of precipitation (the redissolution of the crystals when a dry atmosphere is reinstated) also suggests that the phase diagram for this system is a function of the water vapor partial pressure in the atmosphere. The fact that crystallization and nucleation rate increased in the presence of water vapor also suggests that there is a structural modification to the melt in the presence of water vapor. Thus, it is important to quantify the humidity of the atmosphere when measuring the solidification behavior of liquid slags. The effect of water vapor on mold slag crystallization has been studied by means of the DHTT. The following results were found. 1. The nucleation rate and crystal growth rate increased significantly in the presence of water vapor. 2. Crystallization occurred above the determined liquidus temperature for the system in a dry atmosphere, suggesting that the interaction of water vapor with the slag changed the position of the liquidus. 3. The stability of the crystalline phase in humid atmospheres was directly related to the presence of water vapor in the atmosphere. 4. Experimental evidence of both water absorption and desorption was observed.
The authors thank the member companies of the Center for Iron and Steelmaking Research for their support. In particular, the support from Philippe Rocabois, IRSID, is gratefully acknowledged.
REFERENCES 1. J. Dubrawski and J. Camplin: J. Thermal Analysis, 1993, vol. 40, pp. 329-34. 2. K. Mills, M. Susa, and V. Ludlow: ISS Process Technol. Conf., Iron & Steel Society, Warrendale, PA, 1995, vol. 13, pp. 157-62. 3. H. Sakai, T. Kawashima, T. Shiomi, K. Watanabe, and T. Iida: Molten Slags, Slags and Salts 897 Conf., Iron & Steel Society, Warrendale, PA, 1997, pp. 787-90 4. R. Sato: Mold Slages for Ingot and Continuous Casting of Steel, Nippon Thermochemical Co., Tokyo, 1983. 5. E. Turkdogan: Physicochemical Properties of Molten Slags and Glasses, The Metals Society, London, 1983. 6. J. Chavez, A. Rodrigues, R. Morales, and V. Tapia: ISS Steelmaking Proc., Iron & Steel Society, Warrendale, PA, 1995, pp. 679-86 406—VOLUME 31B, APRIL 2000
7. Yoshiaki Kashiwaya, Carlos E. Cicutti, Alan W. Cramb, and Kuniyoshi Ishii: Iron Steel Inst. Jpn. Int., 1998, vol. 38 (4), pp. 348-35. 8. Yoshiaki Kashiwaya, Carlos E. Cicutti, and Alan W. Cramb: Iron Steel Inst. Jpn. Int., 1998, vol. 38 (4), pp. 357-65. 9. C. Orrling, A. Tilliander, Y. Kashiwaya, and A.W. Cramb: Trans. Iron Steel Soc., 2000, vol. 27 (1), pp. 53-63. 10. L.E. Russel: J. Soc. Glass Technol., 1957, vol. 41, p. 304T. 11. J.W. Thomlinsson: J. Soc. Glass Technol., 1956, vol. 40, p. 25T. 12. J.H. Walsh, J. Chipman, T.B. King, and N.J. Grant: Tra
Data Loading...
