| Project/Area Number |
62550493
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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 |
金属精錬・金属化学
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| Research Institution | Kumamoto University |
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Principal Investigator |
MITSUO Toshiharu Faculty of Engineering, Kumamoto University. Professor, 工学部, 教授 (80166058)
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| Co-Investigator(Kenkyū-buntansha) |
SUNAYAMA Hiroyuki Faculty of Engineering, Kumamoto University. Assistant, 工学部, 助手 (30040413)
KAWAHARA Masayasu Faculty of Engineering, Kumamoto University. Associate Professor, 工学部, 助教授 (60145282)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1988: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1987: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Dolomite / Burnt dolomite / Fluxing of burnt dolomite / Hydration of burnt dolomite / Dolomite for refining / Dolomite for steelmaking / Refining of LD converter / Flux for refining / 鉄鋼用ドロマイト / 転炉製錬 |
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| Research Abstract |
Several properties of dolomites, produced from six areas in Japan, were investigated. Additional experiments were carried out to study the relationship between hydration reactivity of burnt dolomites and fluxing property to molten slag.
1. Reaction process of burnt dolomite: The reaction process of burnt dolomites can be divided into two stages in both hydration and fluxing. One is breaking stage in which the burnt dolomite breaks into small particles to be suspended in agitated water or slag due to macro crack. Another is dissolution stage in which CaO and MgO are dissolved from the surface of each particle due to chemical reactions. The reactivity of burnt dolomites is determined by macroscopic surface area and microscopic surface area. That is the area of surface of each particle produced in braking stage and this is due to clearance among micro grains formed in calcination.
2. Hydration reactivity: In lower calcination temperature, hydration reactivity of burnt dolomite is affected by the grain size at raw state. Large grain promotes the formation of so many macro cracks even at lower temperature as to kept the hydration reactivity high. On the other hand, hydration reactivity of burnt dolomite with small grain size becomes higher according to formation of more macro cracks at higher calcination temperature. At much higher calcination temperature, however, decrease of microscopic surface area due to recrystallization leads the reduction of hydration reactivity regardless of the grain size.
3. Fluxing property: Fluxing property becomes smaller with increase of calcination temperature. But, this reduction in fluxing property is not so remarkable as that in hydration reactivity. The reason is that the erosion ability of employed acid slag, including a plenty of FeO, to burnt dolomite is large, so fluxing property does not fall down so much at high calcination temperature.
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