Hideaki Suito

Calcium deoxidation equilibrium in liquid iron

Calcium-oxygen equilibrium was studied at 1873 K under normal pressure by the method of immersing a pure iron capsule containing calcium metal into liquid iron, which was equilibrated with CaO-Al2O3 slags in Al2O3 and CaO crucibles. On the basis of these and previous results obtained in the equilibrium experiments between liquid iron and CaO-containing slags, the equilibrium constant,KCa, for the reaction, CaO (s) =Ca +O, and the first-order interaction parameter,e0Ca, were estimated. The measured value forKCa reported in previous experiments, which was found to be significantly different from that calculated from the reliable thermodynamic data, was discussed. Nitrogen distribution ratios between CaO-Al2O3 slags and liquid iron were also measured.

Activities in CaO-SiO2-Al2O3 slags and deoxidation equilibria of Si and Al

The activities of MnO and SiO2 along the liquidus line in the MnO-SiO2-Al2O3-FetO (1.2 to 6.7 mass pct) system were determined at 1823 and 1873 K by using a slag-metal equilibration technique. On the basis of the re-evaluated MnO iso-activity curves, the SiO2 and Al2O3 iso-activity curves were determined by using the ternary Gibbs-Duhem relation. The control of inclusions composition in Si-Mn killed steels is discussed based on the equilibria between inclusion and steel with respect to Si, Mn, Al, and O.

Thermodynamics of oxygen and nitrogen in liquid iron equilibrated with CaO- SiO2-Al2O3 slags

Nitrogen distribution ratios, LN ( = (mass pct N)/[mass pct N]), between CaO-SiO2-Al2O3 slags and liquid iron were measured at 1823 and 1873 K as a function of Si (or Al) content in metal, using lime and alumina crucibles. Based on these results and the reported values for activities of SiO2 (or Al2O3), nitride capacities, C(N), defined by (mass pct N) · PO2/3/4/PN2/1/2 were evaluated. Activities of SiO2 (or Al2O3) obtained by using the values for LN and C(N) obtained in present and previous gas-slag experiments were compared with previous results.

Activities of MnO in CaO-SiO2-Al2O3-MnO (<10 Pct)-FetO(<3 pct) slags saturated with liquid iron

Activity coefficients of MnO and Fe,0 in CaO-SiO2-Al2O3-MnO(<10 mass pct)-Fe,O(<3 mass pct) slags were determined at 1873 K in an Al2O3 or CaO crucible by using the reported values for the activities of Al2O3 and SiO2 or the analyzed contents of oxygen. The activity coefficients of MnO and FetO were found to be constant in the studied concentration range of MnO and FetO. The former increased with an increase in the CaO content, while the latter increased with an increase in the SiO2 content.

Activities of FetO in CaO-Al2O3-SiO2-FetO (<5 Pct) slags saturated with liquid iron

The activity coefficients of FetO in CaO-Al2O3 and CaO-Al2O3-SiO2 slags with 0.01 to 5 mass pct FetO were determined at 1873 K from the data obtained in the present and previous slag-metal experiments, using an alumina or lime crucible. It was found that the activity coefficients of FetO obeyed a dilute solution law and increased with increasing the content of SiO2. Based on the findings pertaining to the activity coefficient, the values for the activities of SiO2 and Al2O3 in CaO-Al2O3-SiO2 slags were assessed.

Thermodynamics of O, N, and S in liquid Fe equilibrated with CaO-AI2O3-MgO slags

Nitrogen and S distribution ratios between CaO-Al2O3-MgO slags and liquid Fe were measured at 1873 K as a function of Al (or Mg, Ca) content in metal, using CaO, MgO, and A12O3 crucibles. Based on the results for the solubility product of MgO, the equilibrium constant,KMg, for the reaction MgO =Mg +O and the first-order interaction parameter,eOMg (eMgO), were estimated to be logKMg = -7.8 ± 0.2 andeOMg = -190 ± 60 (eMgO = -290 ± 90), respectively. The activities of A12O3 at the slag compositions double-saturated with CaO/MgO, MgO/ MgO A12O3, and MgO Al2O3/CaO 2A12O3 components were obtained from the S distribution ratios between slag and metal, coupled with the reported values of sulfide capacities. Nitride capacities were also estimated from the N distribution ratios and the activities of A12O3.

Silicon-Oxygen equilibrium and nitrogen distribution between CaO-SiO2 slags and liquid iron

AbstractSilicon-oxygen equilibria in an Fe-0.003 ~ 27 mass pct Si alloy in equilibrium with the CaO-SiO2 slags were studied in the temperature range of 1823 to 1923 K using a lime crucible. At the same time, nitrogen distribution ratios, LN, between slag and metal were measured, and from these results and the reported values for activities of SiO2, nitride capacities, % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfKttLearuqr1ngBPrgarmWu51MyVXgatC% vAUfeBSjuyZL2yd9gzLbvyNv2CaeHbd9wDYLwzYbItLDharyavP1wz% ZbItLDhis9wBH5garqqtubsr4rNCHbGeaGqiVy0df9qqqrpepC0xbb% L8F4rqqrFfpeea0xe9Lq-Jc9vqaqpepm0xbba9pwe9Q8fs0-yqaqpe% pae9pg0FirpepeKkFr0xfr-xfr-xb9adbaqaaeGaciGaaiaabeqaam% aaeaqbaaGcbaaceiGaa83qamaaBaaaleaaiqaacaGFobWaaWbaaWqa% beaacaGFZaGaeyOeI0caaaWcbeaaaaa!3DDE!

Cryoscopic studies in fluoride-oxide-silica systems: Part I. systems containing Li+, Na+ and K+

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