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Electrochemical reaction of ions in molten slags with electron in thermal plasma

熔渣中的离子与热等离子体中的电子发生电化学反应

基本信息

批准号：
11450237
负责人：
NAGATA Kazuhiro
金额：
$ 9.47万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11450237/
关键词：
arc Plasma electrochemistry slag evaporation refractivity arc plasma electrochemistry vaporization slag ash

项目摘要

The behavior of oxides FeO-SiO_2 melted by Ar arc plasma has been investigated. A direct-current transfer/non-transfer-hybrid-type generator was employed. A cavity was formed at the arc spot of plasma and the depth was determined by the balance between the hydrostatic pressure and the sum of the pressure caused from both of the arc and the gas flow. Molten slag on the surface flowed from center to the edge of melt because of aerodynamic drag force. FeO-SiO_2 glasses cont aining Zn were melted by Ar-O_2 plasma arc. From spectroscopic measurement, the parial pressure of Zn vapor exponentially decreased with time. The evaporation rate of Zn at the plasma spot is controlled by diffusion in gas phase and decreases with increasing the partial pressure of oxygen. 40CaO-40SiO_2-20Al_2O_3 (mass%) slag and that containing iron oxide were melted by Ar plasma arc. Fe^<3+> in molten slag was rapidly reduced to Fe^<2+>. Then, the evaporation rate is affected by the partial pressure of oxugen. 25mol%Na_2O-75mol%SiO_2 molten slag was electrically analyzed by transfere-arc plasma with ironplate as a anode. The amount of oxidation of iron at the anode was according to Faraday's law. Then, the reaction of Na_2O+Fe→FeO+2Na^++2e takes place. The ratio of Na/Si increased and the amount of SiO gas evaporated in 100 to 1000 times larger than that expected by Faraday's law. Then, the reaction of SiO_2(slag)+2e→SiO(g)+O^<2-> (slag) would take place at the surface of molten slag with the electro-neutrality reaction of SiO_2(slag)+2e+2Ar^+→SiO(g) +(1/2)O_2+2Ar.

研究了Ar弧等离子体熔化氧化物FeO-SiO_2的行为。采用直流转移/非转移混合型发电机。在等离子体的电弧点处形成空腔，其深度由静水压力与电弧和气流引起的压力之和之间的平衡来确定。由于空气动力阻力，表面的熔渣从熔体中心向边缘流动。采用Ar-O_2等离子弧熔炼含Zn的FeO-SiO_2玻璃。根据光谱测量，锌蒸气的面压随时间呈指数下降。等离子点处Zn的蒸发速率受气相扩散控制，并随着氧分压的增加而降低。采用Ar等离子弧熔炼40CaO-40SiO_2-20Al_2O_3(mass%)炉渣和含氧化铁的炉渣。熔渣中的Fe^3+迅速还原为Fe^2+。然后，蒸发速率受到氧气分压的影响。以铁板为阳极，采用转移弧等离子体对25mol%Na_2O-75mol%SiO_2熔渣进行电分析。阳极处铁的氧化量根据法拉第定律。然后，发生Na_2O+Fe→FeO+2Na^++2e的反应。 Na/Si的比例增加，SiO气体的蒸发量比法拉第定律预期的大100至1000倍。然后，在熔渣表面发生SiO_2(渣)+2e→SiO(g)+O^<2->(渣)的反应，并发生SiO_2(渣)+2e+2Ar^+→SiO(g)+(1/2)O_2+2Ar的电中性反应。