| Budget Amount *help |
¥8,600,000 (Direct Cost: ¥8,600,000)
Fiscal Year 1991: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1990: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Research Abstract |
1. An argon-oxygen mixture was blown onto the surface of molten iton for decarburization. Even though the oxygen partial pressure was quite low, an oxide film formed on the melt surface and reduced the rate of decarburization. The experimental result is explained by a reaction model in which the rate process at the oxide film is considered.
2. In experiments of decarburization of molten iron in magnesia, alumina and calcia crucibles with blowing argon gas, carbon in the melt reacted with crucible oxides to form CO. A reaction model is proposed in which the dissociation reaction of the oxide, CO formation reaction at the crucibleoxide interface, etc. are taken into account. The model can explain the experimental results.
3. In order to enhance the decarburization rate of molten iron and ironchromium alloy with solid oxides, the vacuum suction degassing method was adopted for decarburization in a very low carbon concentration range. The principle of the method'is that the CO gas formed at the reaction interface is sucked through the porous oxide, the other side of which is kept at a vacuum. The decarburization experiments were made by immersing a porous tube into the melt. The inside of the tube was evacuated. The components of the tube were Al_2O_3, SiO_2, MnO, Fe_2O_3, Cr_2O_3, etc. The decarburiza-tion rate was higher for the oxide of higher dissociation pressure and the tube of larger porosity. An Al_2O_3-SiO_<> tube could decarburize the melt much faster than an Al_2O_3 tube. Moreover, the decarburization rate was higher for the tube containing SiO_2 in the form of cristbalite (SiO_2) than in the form of mullite (3Al_2O_3・2SiO_2). The melt tended to penetrate into the pore of Al_2O_3-Fe_2O_3 tube.
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