Decuprization and Purification of molten steel by ammonia gas
| Project/Area Number |
08555179
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Metal making engineering
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
SUZUKI Ryosuke O. Kyoto University, Department of Energy Science and Technology, Associated Professor, エネルギー科学研究科, 助教授 (80179275)
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| Co-Investigator(Kenkyū-buntansha) |
ONO Katsutoshi Kyoto University, Department of Energy Science and Technology, Professor, エネルギー科学研究科, 教授 (10026049)
小野 勝敏 京都大学, エネルギー科学研究科, 教授 (08875059)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1996: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | Ammonia / Decuprization / Scrap / Recycle / Evaporation / 清浄化 / スプラッシュ / 窒化物 |
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| Research Abstract |
The purpose of this research is to recycle the steel scrap and to pbtain the cold-rolling grade steel by the secondary refining with copper removal. We confirmed an industrial applicability from the technical view by some experiments that the ammonia nustavle at the higher temperatures was blown to the molten steel. After blowing against the normal steel SS41 containing 1.0%Cu, for example, for 30min. under the continuous evacuation (about 10Torr) and strong stirring condition, copper was removed to 100mass ppm, carbon to 10ppm, oxygen and sulfur to a 10ppm level, and phosphor to 150ppm. However, nitrogen content was so high as 150ppm that we judged that a post-vacuum treatment was required. Accompanying degassing after ammonia top blowing, nitrogen decreased to 5ppm. The ammonia decuprization proceeded at 10 times faster rate than vacuum treatment. It reached to a limit when the present small crucible was used at the laboratory scale, because the effect of interface area on the reaction rate was large. Arranging the rate determine equation to adjust the industrial operation, a good calculation result was obtained that it is possible to remove copper and purify the molten steel within the same time as the present secondary refining process, assuming the wider reaction interface at RH method.
The evaporation phenomenon by ammonia from pure copper liquid was visualized by the laser flash method to discuss the mechanism. Abnormal evaporation by ammonia gas blowing on molten pure Cu, Ge and Sn was recorded. The mechanism was discussed that the unstable hydride or nitride is produced by the interaction between these metals and the decomposing ammonia gas. In the high concentration of alloys, in addition to this mechanism, the splash forming introduced by over-saturated nitrogen in the alloy melts was largely contributed.
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Report
(3 results)
Research Products
(11 results)
