1994 Fiscal Year Final Research Report Summary
Recovery of Metal Resources from Wastes using Thermal Plasma
| Project/Area Number |
05680387
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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 |
プラズマ理工学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
KANZAWA Atsushi Tokyo Inst.of Tech., Faculty of Eng.Professor, 工学部, 教授 (80010908)
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| Co-Investigator(Kenkyū-buntansha) |
SEKIGUCHI Hidetoshi Tokyo Inst.of Tech., Faculty of Eng., Research Associate, 工学部, 助手 (50226643)
WATANABE Takayuki Tokyo Inst.of Tech., Faculty of Eng.Research Associate, 工学部, 助手 (40191770)
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| Project Period (FY) |
1993 – 1994
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| Keywords | thermal plasma / wastes / resource recovery / ceramics / flyash / reaction mechanisms |
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| Research Abstract |
The purpose of the research is to teat flyash produced from a incinerator and to recover metal resources from the flyash using a reactive thermal plasma. As a fundamental study, five kinds of metal oxides were treated by the thermal argon plasma with the addition of four kinds of gases. The reaction mechanisms between the reactive plasma and metal oxides were estimated by considering the analyzes of products and residual sample, and calculation of Gibbs' free energy change. The results showed that the reaction passes were classified according to the following reaction ; thermal decomposition in the sample, surface reaction, thermal decomposition in gas phase, reaction in gas phase. The further study was carried out to elucidate the reaction mechanisms. Magnesia, silica and alumina were chosen as a metal oxide and hydrogen was added into the thermal argon plasma. In the treatments of magnesia and silica, hydrogen addition enhanced the decrease in the oxide samples. The weight decreasing rate was in proportion to the root of hydrogen concentration and the intensity of hydrogen atom emission, suggesting hydrogen atom took part in the reaction. Magnesium was recovered from the plasma treatment of magnesia, however silicon was not recovered from silica. According to the consideration of the experimental results, equilibrium compositions, and surface temperature, the reaction mechanisms was proposed including the deoxidation and evaporation. In alumina treatment, no weight change in the sample was observed because alumina was thermodynamically stable at estimated surface temperature. The study will be continued using mixed metal oxide samples and finally the recovery process in the plasma treatment of flyash will be proposed.
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Research Products
(5 results)
