A Thermodynamic Model for Prediction of Iron Oxide Activity in Some FeO‐Containing Slag Systems

Abstract

A thermodynamic model for calculating the mass action concentrations of structural units in CaO-SiO 2 -MgO-FeO-MnO-Al 2 O 3 -CaF 2 slags, i.e., the IMCT-N i model, has been developed based on the ion and molecule coexistence theory (IMCT). The calculated comprehensive mass action concentration of iron oxides N Fe t O has been compared with the reported activity of iron oxide a Fe t O in 14 FeO-containing slag systems from literatures. The good agreement between the calculated N Fe t O and reported a Fe t O indicates that the developed IMCT-N i model can be successfully applied to predict the activity of iron oxide a Fe t O as well as the slag oxidation ability of CaO-FeO (s1), SiO 2 -FeO (s2), CaO-SiO 2 -FeO (s3), CaO-FeO-Al 2 O 3 (s4), SiO 2 -MgO-FeO (s5), SiO 2 -FeO-Al 2 O 3 (s6), CaO-SiO 2 -FeO-Al 2 O 3 (s7), CaO-SiO 2 -MgO-FeO-Al 2 O 3 (s8), SiO 2 -FeO-MnO (s9), SiO 2 -FeO-MnO-Al 2 O 3 (s10), FeO-MnO (s11), FeO-MnO-Al 2 O 3 (s12), CaO-FeO-CaF 2 (s13), and CaO-SiO 2 -FeO-CaF 2 slags (s14) in a temperature range of 1473-1973 K.

Critical Assessment of P2O5 Activity Coefficients in CaO-based Slags during Dephosphorization Process of Iron-based Melts

“…Thus, activity a R;Fe of Fe as solvent in metal film relative to pure matter as a standard state as well as activity coefficient f %;i of [O] and [P] in metal film can be considered to be close to 1.0. Moreover, many studies had indicated [6][7][8]27,28] that activity a Fe t O of Fe t O in metallurgical slags can precisely be described by the defined comprehensive mass action concentration N Fe t O of iron oxides based on the MCT. [5][6][7][8][22][23][24][25][26][27][28][29][30][31][32] …”

“…The calculated [22] values of the mass action concentration N P 2 O 5 of P 2 O 5 in the CaO-based slags by the IMCT [5][6][7][8][22][23][24][25][26][27][28][29][30][31][32] are also tabulated in Table I. Comparison between the calculated [ Figure 1 [7c] are greater than the calculated [22] results of N P 2 O 5 about 100 times as shown in Figure 1 [9c] are much smaller than the calculated [22] results of N P 2 O 5 about 10 10 times as illustrated in Figure 1 Figure 1(c).…”

“…To critically evaluate the collected ten models [9][10][11][12][13][14][15][16][17][18][19][20][21] of c P 2 O 5 , the activity coefficient c P 2 O 5 of P 2 O 5 in a CaO-based slags for hot metal dephosphorization at a commercial-scale hot metal pretreatment station has first been determined by the ion and molecule coexistence theory (IMCT). [5][6][7][8][22][23][24][25][26][27][28][29][30][31][32] After that, the collected ten models [9][10][11][12][13][14][15][16][17][18][19][20][21] of c P 2 O 5 have critically been evaluated based on the determined results of c P 2 O 5 in the CaO-based slags by the IMCT [5][6][7][8][22][23][24]…”

Critical Evaluation of Prediction Models for Phosphorus Partition between CaO-based Slags and Iron-based Melts during Dephosphorization Processes

“…Finally, a general method for developing the prediction model of k P or L P with ideal accuracy from the reported models has been suggested or provided through revising the collected models for the assigned slags equilibrated with molten steel or hot metals. In addition, the developed L P model [84] based on the ion and molecule coexistence theory (IMCT) [81][82][83][84][85][86][87][88][89][90][91][92][93][94] for slags, i.e., the IMCT-L P model, [84] for hot metal dephosphorization by CaObased slags has also been assessed through comparison with the predicted results by the revised models from the literature.…”

Deoxidation Mechanism of Al-Killed Steel during Industrial Refining Process

“…6, the activity of FeO for that mole fraction is in the range of 0.01-0.03. In fact, many scholars 4,16,21,[24][25][26] have investigated the activity of FeO in slag, and most activity values were in the range of 0.01-0.03.…”