Influence of additives on sulfide capacity of CaO-CaF 2 -SiO 2 slags
- PDF / 348,615 Bytes
- 4 Pages / 603.28 x 783.28 pts Page_size
- 5 Downloads / 237 Views
(J/mol)
[2]
where P is dissolved in pure liquid iron. The new equilibrium constant value is also approximately 50 pct smaller than the previous one, since the phosphorus distribution ratio between slag and metal is given by (pct P)/[pct P] = k 2 Me MstagfP aca/'~s 1.5
[3]
The most relevant data in terms of phosphorus partition ratio are shown in Figure 3. The curves increase only slightly, 4 pct from the previous values, indicating that the two changes almost compensate each other. Therefore, the phosphorus distribution ratio and the trend of the curves for the hypothetical treatment are the same as previously stated. REFERENCES 1. N. Masumitsu, K. Ito, and R.J. Fruehan: Metall. Trans. B, 1988, vol. 19B, pp. 643-48. 2. D.J. Min and N. Sano: Metall. Trans. B, 1988, vol. 19B, pp. 433-39. 3. M. Kohler and H.J. Engell: 2ndlnt. Symp. on Metallurgical Slags and Fluxes, TMS-AIME, Lake Tahoe, NV, 1984, pp. 483-93.
Influence of Additives on Sulfide Capacity of CaO-CaFa-SiOa Slags KATSUJIRO SUSAKI, M A S A F U M I M A E D A , and N O B U O SANO In most Japanese integrated steelmaking plants, hot metal pretreatment is a common practice, because the combination of the pretreatment with the combined blowing converter minimizes the production cost of highquality steel. The CaO-CaF2-SiO2 system containing lower SiO2 is an excellent slag for desulfurization, as reported elsewhere, m In the actual hot metal pretreatment, the oxides, such as alumina, magnesia, and manganese oxide, are inevitable because of the erosion of refractory or residues in previous processes. Sometimes even additions of such oxides are made in the pretreatment. Therefore,
KATSUJIRO SUSAKI, formerly Graduate Student with the Department of Metallurgy, the University of Tokyo, is with Comanhia Siderurgica Paulista-COSBaA, Brazil. MASAFUMI MAEDA, Associate Professor, Institute of Industrial Science, and NOBUO SANO, Professor, Department of Metallurgy, are with the University of Tokyo, 7-22-1 Roppongi, Minoto-ku, Tokyo, 106. Manuscript submitted March 8, 1990. METALLURGICAL TRANSACTIONS B
it is of practical importance to know how these additives or contaminants affect the desulfurization capacity of slags. In the present study, the influences of Na20, A1203, MgO, and MnO on the sulfide capacity of CaO-CaF2SiO2 slags were studied. The addition of Na20 was also investigated to understand how it enhanced the sulfide capacity. Emphasis was given to slags of CaO-saturated composition, not only because they have the highest sulfide capacity but also because of the presence of excess CaO in the commercial slags. The sulfide capacity was originally defined by a gasslag reaction," [2] as in Eq. [1]. It can be expressed in terms of sulfur partition, as in Eq. [3], by considering the dissolution of sulfur into a metal (Eq. [2]). 1/2S2 + 0 2 - = 1/202 + S 2-
[1]
1/2S2 (g) = [S]
[2]
S 2 --- (Pct $2-) 9(Po2/Ps2) 1/2 = Kl" a o > / f s 2= ((Pct S2")/[Pct S]) 9(Po2) 1/2- K2/fs
[31
where [Pct S] = (Pct S z-) = f s 2- = fs = K~ =
wt pct of S in a metal; wt pct of S in
Data Loading...
