Abstract
Use of carbonaceous particles such as coke or coal char in controlling slag foaming is of great practical significance for bath-smelting and other steelmaking processes. The foamability of the liquid slag in terms of the foam index has been determined with the presence of different amounts of coke and coal char particles. Different sized and shaped particles were used in the experiments. It was found that the foam index decreased significantly as the ratio of the total cross-sectional area of the particles to the liquid slag surface area increased. When the foam was generated by argon gas injection through an alumina nozzle (i.d. = 1.5 mm), a liquid slag, CaO-SiO2-CaF2-(Al2O3), depending on the alumina content, could have an initial foam index of about 2 to 4 seconds at 1500 °C without any carbonaceous particles. When the slag surface was covered only 15 ~20 pct with either coke or coal char particles, the foam was totally suppressed regardless of the initial foam index. In order to understand the mechanism of the antifoam effect of the carbonaceous particles, interactions of a coke sphere, an iron ore pellet, an alumina tube, and a coal char particle with the liquid slag foam were examined by X-ray observation. It was concluded that the antifoam effect of coke or coal char particles is primarily contributed by the nonwetting nature of the carbonaceous materials with the liquid slag. Possible mechanisms of carbonaceous particles rupturing a slag film could be (1) the rapid thinning of the liquid slag film driven by a difference between the instantaneous contact angle and the equilibrium contact angle or (2) the “dewetting” of the liquid slag from the interface when the film is “bridged” by the particle.
Similar content being viewed by others
References
K. Ito and R.J. Fruehan:Metall. Trans., 1989, vol. 20B, p. 509–514.
R. Jiang and RJ. Fruehan:Metall. Trans., 1991, vol. 22B, p. 481–489.
R. Roth, R. Jiang, and R.J. Fruehan:Trans. Iron Steel Inst., 1992, Nov., pp. 55–63.
Y. Zhang and R.J. Fruehan:Metall. Mater. Trans. B, 1995, vol. 26, pp. 000-.
M. Matsuo:Tetsu-to-Haganeá, 1986, vol. 72, p. S970 (in Japanese).
H. Iso, K. Arima, M. Kanemoto, Y. Ueda, and H. Yamane:Trans. Iron Steel Inst. Jpn., 1988, vol. 28, p. 382–391.
N. Tokumitsu, M. Matsuo, H. Katayama, H. Ishikawa, Y. Takamoto, and Y. Hayashi:Process Technology Conference Proc, ISS/AIME, Toronto, 1988, p. 99–107.
Y. Ogawa, H. Katayama, H. Hirata, N. Tokumitsu, and M. Yamauchi:International Iron Steel Inst. Jpn., 1992, vol. 32, p. 87–94.
Y. Ogawa and N. Tokumitsu:Proc. of 6th International Iron and Steel Congress, ISIJ, Nagoya, Japan,) 1990, p. 147–152.
P.R. Garrett:J. Colloid Interface Sci., 1979, vol. 69, p. 107–121.
A. Dippenaar:Int. J. Miner. Proc, 1982, vol. 9, p. 1–22.
I. Jimbo: Carnegie Mellon University, Pittsburgh, PA, private communication, 1992.
R.S. Sampaio, R.J. Fruehan, and B. Ozturk:Trans. Iron Steel Soc, 1993, vol. 14, p. 59–67.
Author information
Authors and Affiliations
Additional information
Formerly Graduate Student and Research Associate, Department of Materials Science and Engineering, Carnegie Mellon University.
Rights and permissions
About this article
Cite this article
Zhang, Y., Fruehan, R.J. Effect of carbonaceous particles on slag foaming. Metall Mater Trans B 26, 813–819 (1995). https://doi.org/10.1007/BF02651728
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02651728