1995 Fiscal Year Final Research Report Summary
Effect of addition of surface active element on supersaturation in iron melt
| Project/Area Number |
06650827
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Metal making engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
INOUE Ryo Tohoku University, Institute for Advanced Materials Processing, Associate Professor, 素材工学研究所, 助教授 (70111309)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Jun-ichi Tohoku University, Institute for Advanced Materials Processing, Research Associa, 素材工学研究所, 助手 (20261472)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Surface active element / Supersaturation / Liquid iron / Alumina / Precipitation / Interfacial energy / Hercynite |
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| Research Abstract |
The supersaturation and equilibrium experiments were carried out at 1873K by using Fe-Al alloys and CaO-Al_2O_3 slags in an Al_2O_3 crucible, and the effects of Te addition and cooling rate on supersaturation were studied. The conclusions were summarized as follows.
1. Total oxygen content for a given total aluminum content obtained in equilibrium and supersaturation experiments without Te was not influenced by the cooling rate.
2. In supersaturation experiments with Te addition, total oxygen contents decreased to a constant value as a result of the removal of precipitated Al_2O_3 in the range of [% Te]>0.005 and the degree of lowering increased with a decrease in cooling rate.
3. The critical supersaturation ratio was estimated to be about 10^2 by considering the effect of Te on the interfacial energy between liquid iron and alumina.
4. Tellurium distribution ratio between an Fe-Al alloy and CaO-Al_2O_3 slag was found to be linearly related to the aluminum content in logarithmic form with a slope of 2/3, suggesting that Te in slag is present as divalent anion.
An Fe-0.03-0.44mass% Al alloy or an Fe-0.07-0.58mass% Al-0.2-0.6mass% Te alloy was reoxidized with the Fe_tO(<3mass%)-containing CaO-Al_2O_3 slags at 1873 K for 5 and 60 min. The effects of slag compositions, Te addition and initial Fe_tO contents on the reoxidation of aluminum were studied. The following conclusions were obtained .
1. Acid-insoluble Al as primary inclusions containing alumina, hercynite and Fe_tO-Al_2O_3 mixture was observed in the experiments of using CaO-Al_2O_3-Fe_tO slags saturated with an Al_2O_3 crucible at 5 min.
2. The oxygen in liquid iron was supersaturated in the rapid cooling experments except those of the CaO-Al_2O_3-Fe_tO slags saturated with an Al_2O_3 crucible at 60 min with Te addition.
3. The relations between Fe_tO and Al contents were observed to be in equilibrium in the experiments except those of the CaO-Al_2O_3-Fe_tO slags saturated with an Al_2O_3 crucible at 5 min.
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