| Project/Area Number |
63550488
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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 | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
TSUKIHASHI Fumitaka THE UNIVERSITY OF TOKYO, FACULTY OF ENGINEERING, ASSOCIATE PROFESSOR, 工学部, 助教授 (60155348)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1989: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1988: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Slag / Flux / Nitrogen / Solubility / Nitride ion / Thermodynamics / Silicate / 窒素溶解度 / シリケート |
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| Research Abstract |
The solubility of nitrogen in various flux systems was investigated by the chemical equilibration technique in order to know the physicochemical properties of nitrogen in molten flux. The compositions of fluxes investigated in the present study varied from the acidic flux being used in glass industry to basic flux for the iron and steelmaking. The effects of composition of fluxes, partial pressures of oxygen and nitrogen and temperature on the nitrogen solubility were measured and following results were obtained.
1. The solubility of nitrogen in CaO-CaF_2 melts was constant with changing the oxygen partial pressure from 10^<-6>atm to 10^<-11>atm at 1375ﾟC. 2. The solubilities of free nitride ions and incorporated nitride ions were measured at 1550ﾟC for the CaO-SiO_2 system. It has been proposed that nitrogen dissolves in melts by two mechanisms, namely as free nitride ions and incorporated nitride ions. 3. The solubilities of nitrogen in CaO-CaF_2-SiO_2 fluxes were measured on the liquidus at 1300ﾟC. The change in total nitrogen content in CaO-CaF_2-SiO_2 system is the complicated reflection of various effects such as the free and incorporated nitride dissolution and fluorosilicate formation. 4. The dependence of nitrogen solubility on the flux compositions was observed for the CaO-MgO-SiO_2 and BaO-MgO-SiO_2 systems at 1450ﾟC. The solubility for the CaO-MgO-SiO_2 system is higher than that for the. BaO-MgO-SiO_2 system. For both systems, the free nitride ions decreased and the incorporated nitride ions increased with increasing SiO_2 content.
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