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STUDY ON IMPROVING DEGASSING EFFICIENCY OF IRON MELT WITH VACUUM SUCTION DEGASSING METHOD

真空抽吸脱气法提高铁水脱气效率的研究

基本信息

批准号：
06555221
负责人：
SANO Masamichi
金额：
$ 4.74万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

项目摘要

Experimental studies on decarburization, dehydrogenization and dcoxidation have been performed for improving the efficiency of degassing of iron melt with applying the vacuum suction degassing method. This degassing method is based on using a porous refractory material, which separates the melt from the outer space under a vacuum condition. The degassing reaction takes place at the melt-porous material interface and the gascous products are easily removed from the interface by permeating the porous material. The necessary condition is that the melt should not permeate the material. Since the area of the melt-porous material interface can be arbitrarily increased, it is possible to increase the degassing rate optionally.As for decarburization of iron melt, with using solid oxide, an attempt was made to obtain a high decarburization rate by immersing an Al_2O_3-2-30%Fe_2O_3 porous tube in the melt. The decarburization proceeded by the reaction between C and Fe_2O_3 (amd/or O). The decarb … More urization increased with increasing Fe_2O_3 content of the tube, but the oxygen content of the melt also increased. In addition, since the hot strength of the tube of high Fe_2O_3 content was not sufficient, deformation of the tube took place during the experiment at lower internal pressure of the tube, and the gas permeability of the tube decreased. In this case, the decarburization rate also decreased. Hence, the Al_2O_3-Fe_2O_3 tube was not superior in the decarburization rate to the Al_2O_3-SiO_2 tube used in our previous experiments.Experiments on dehydrogenization of iron melt were made with blowing Ar gas onto the melt surface and with or without immersing an Al_2O_3 prorous tube. It is shown that the dehydrogenization rate is controlled by gas-and liquid-phase mass transfers. The mass transfer coefficients for the tube-melt interface and obtained by applying a mixed control model. The gas-phase mass transfer coefficients is larger for the tube of higher gas permeability.Dcoxidation experiments of iron melt were made with immersing MgO-10-30%C porous tube. Oxygen in the melt reacted with C of the tube to form CO and/or with Mg vapor produced by the MgO-C reaction to form MgO,and the dcoxidation proceeded effectively. Dcoxidation experiments were also made with immersing a MgO prorous tube filled with MgO-C powder. In this case, oxygen in the melt could react only with Mg vapor, and contribution of the Mg vapor to the dcoxidation is made clear. Less

为提高铁水的脱气效率，采用真空吸气脱气法进行了脱碳、脱氢和脱钴的实验研究。这种脱气方法是基于使用多孔耐火材料，在真空条件下将熔体与外层空间分离。脱气反应发生在熔体-多孔材料界面上，通过渗透多孔材料，很容易将气泡产物从界面上去除。必要条件是熔体不能渗入材料。由于熔体-多孔材料界面的面积可以任意增加，因此有可能选择性地提高脱气率。对于铁水的脱碳，尝试使用固体氧化物，通过将Al_2O_3-2-30%Fe_2O_3多孔管浸入熔体中来获得高的脱碳率。脱碳是通过C和Fe_2O_3(amd/或O)反应进行的。脱碳…随着管材中Fe_2O_3含量的增加，渗氮量增加，但熔体中的氧含量也增加。此外，由于高Fe_2O_3含量管材的热强度不足，在试验过程中管材在较低的内压下发生变形，导致管材的透气性降低。在这种情况下，脱碳率也有所下降。因此，Al_2O_3-Fe_2O_3管的脱碳速度并不优于我们以前实验中使用的Al_2O_3-SiO_2管。结果表明，脱氢速率受气-液两相传质控制。应用混合控制模型得到了管子-熔体界面的传质系数。气体渗透率越高的管子，气相传质系数越大。采用浸没氧化镁-10-30%C多孔管进行了铁水的脱钴实验。熔体中的氧与管内的碳反应生成CO和/或与镁碳反应产生的镁蒸汽生成氧化镁，有效地进行了脱钴反应。还进行了浸泡在填充有氧化镁碳粉的氧化镁多孔管中的脱钴实验。在这种情况下，熔体中的氧只能与镁蒸气反应，镁蒸气对脱钴氧化的贡献是明确的。较少