Direct Ingot Making of Titanium by Electro-winning from Molten Salt, Using Metal Pool of Titanium

利用钛金属熔池熔盐电积直接制锭

基本信息

批准号：
15206084
负责人：
KAWAKAMI Masahiro
金额：
$ 30.78万
依托单位：
Toyohashi University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15206084/
关键词：
molten salt electorysis with metal pool direct ingot making of titanium ESR unit twin cell current efficiency of electrolysis composition of molten salt reaction model thermo-analysis of process 単セル電解ツインセル電解チタン電解チタンESR 反応機構金属

项目摘要

The purpose of the present research project is to develop the direct ingot making process of titanium by electro-winning of titanium, where the metal pool of titanium is used as the cathode. By using ESR unit, the thermo-analysis of process, electrode reaction mechanism and contamination mechanism were examined.At first, the electrical conductivity of CaO-CaF_2-TiO_2 slag was measured. The effect of TiO_2 addition was so small that the electronic conduction could be neglected. Thus, the addition of TiO_2 to the slag was possible at relatively large amount.By operating ESR unit with steel rod, the relation between shape of metal pool and current-voltage condition was clarified. In the case of ESR, the metal pool could not be obtained at far higher temperature than the melting point of pure titanium. It was seen that the melting point of titanium rose by the absorption of oxygen. Thus, the atmosphere of the whole apparatus, especially, cathode part, must be innert.In the single cell oper … More ation with CaO-CaF_2-TiO_2 slag, the maximum cathodic current efficiency was 12%, and the anodic current efficiency was far less than 100%. The reasons must be 1) formation of metal fog of Ca and its re-oxidation at the anode, 2) formation of Ti^<2+> by the reaction of Ti with Ti^<4+> and its re-oxidation at the anode, and 3) formation of Ti^<2+> by the insufficient amount of Ca and its re-oxidation at the anode. Thus, it is important to control the electrodes distance properly and to control the TiO_2 content properly.On the contrary, by the addition of Al_2O_3 to the slag, c.a. 70 g of electro-deposit and c.a. 60% of cathodic current efficiency were obtained. The reasons must be that the temperature of molten slag should be kept higher temperature by the addition, and that the Al deposit should act as the reductant of Ti^<4+> in the slag. This process is good for producing Ti-Al alloy, but not good for producing pure Ti, because the electro-deposit contained much Al.On the base on the above results, the new apparatus was designed. It consists of twin cell, one of which is anode cell and the other, cathode cell, connected with molten salt bridge. By this apparatus, the distance between cathode and anode can be kept long, resulting in the larger current efficiency and better quality of electro-deposit. The apparatus was successfully operated. Thus, the proposed process is very promising. The above results are published in 6 papers. Less

本研究项目的目的是开发以钛金属熔池为阴极，利用ESR装置，进行过程热分析、电极反应的钛电解直接制锭工艺。首先，测量了CaO-CaF_2-TiO_2渣的电导率，TiO_2的添加影响很小，可以忽略不计。通过使用钢棒操作ESR装置，明确了在ESR无法获得金属池的情况下，金属池的形状与电流-电压条件之间的关系。在比纯钛的熔点高得多的温度下，可以看出钛的熔点因吸收氧而升高，因此整个装置的气氛，特别是阴极部分，必须是惰性的。使用CaO-CaF_2-TiO_2渣进行电解槽运行时，阴极电流效率最高为12%，而阳极电流效率远低于100%，原因一定是1）Ca金属雾的形成及其再生成。阳极氧化，2) 通过 Ti 与 Ti^<4+> 反应形成 Ti^<2+> 及其在阳极的再氧化，以及 3)由于Ca量不足而形成Ti^<2+>并在阳极再次氧化，因此，适当控制电极距离和适当控制TiO_2含量是很重要的。相反，通过添加Ti^<2+>。 Al_2O_3 到炉渣中，获得了约 70 克的电沉积物和约 60% 的阴极电流效率，原因一定是应保持熔融炉渣的温度。由于添加的温度较高，并且Al沉积物应充当炉渣中Ti^<4+>的还原剂，该过程有利于生产Ti-Al合金，但不利于生产纯Ti，因为电沉积。沉积物中含有大量的Al。根据上述结果，设计了新的装置，它由双槽组成，其中一个是阳极槽，另一个是阴极槽，通过该装置，距离。阴极和阳极之间可以保持较长的时间，从而获得更大的电流效率和更好的电沉积质量，因此，所提出的工艺非常有前景，发表在 6 篇论文中。