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Study on the calciothermic reduction of titanium and rare eath metals and the recycle of calcium.

钛与稀土金属的热热还原及钙的回收利用研究

基本信息

批准号：
60470061
负责人：
ONO Katsutoshi
金额：
$ 2.43万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60470061/
关键词：
Titanium Rare Farth Metals Calciothermic Reduction Oxygen in Titanium Deoxidation of Titanium 誘導還元

项目摘要

Titanium with low oxygen content has been expected to be obtainable by direct reduction of titanium dioxide with saturated calcium vapor, because it can remove the oxygen to the extent to which it is able to overcome the affinity of the oxygen for the metal in the solid solution range.A knowledge of the thermodynamic stability of oxygen in the Ti-O solid solution is indispensable in any discussion of the refining of titanium from its oxide. Oxygen in titanium has, however, high stability that ordinary gas equilibration or EMF method using solid electrolyte is not applicable to activity measurement. In this investigation, titanium metal was, therefore, equilibrated under coexistance of saturated calcium vapor and calcium oxide in closed bombs of steel at temperatures between 1173 and 1573 K, quenched and analysed for oxygen. The equilibrium gas concentrations were 300 and 900 mass ppm at 1173 and 1573 K, respectively. The data were then used to derive the relationship among oxygen potential, temperature and composition in the beta -Ti phase field:1/2 ln( <p_(0_2)> /101325Pa)=ln(%O) + 12.1-71900 T 1173-1573 K, (%O)<0.15 mass%Attempts were made to produce titanium by reducing <TiO_2> powders with saturated calcium vapors at 1273 K according to<TiO_2> (s) + Ca(g) = Ti(s) + CaO(s).Electron micrographs of the reduction products showed that the reduced titanium particles were completly surrounded with the solid reaction product, CaO. The reduction rate become very low at the reduction stage at which the decomposition of oxide almost ceased and the deoxidation of the Ti-O solid solution began to take place.

具有低氧含量的钛已经被期望通过用饱和钙蒸气直接还原二氧化钛而获得，因为它可以除去氧，达到能够克服氧对固溶体范围内的金属的亲和力的程度，在从钛的氧化物中精炼钛的任何讨论中，氧在Ti-O固溶体中的热力学稳定性的知识是必不可少的。然而，钛中的氧具有很高的稳定性，普通的气体平衡法或使用固体电解质的电动势法不适用于活度测量。在这项研究中，钛金属，因此，在1173和1573 K之间的温度下，在钢的密闭弹中，在饱和钙蒸气和氧化钙的共存下平衡，淬火并分析氧。平衡气体浓度分别为300和900质量ppm，在1173和1573 K。根据实验数据，导出了β-Ti相区氧势、温度和成分的关系式：1/2ln（<p_（0_2）> /101325 Pa）=ln（%O）+ 12.1-71900 T 1173-1573 K，（%O）<0.15 mass%<TiO_2>在1273 K下，用饱和钙蒸气还原粉末<TiO_2>制备钛，还原产物的电镜观察表明，还原后的钛颗粒被固相反应产物CaO完全包裹。在还原阶段，氧化物的分解几乎停止，Ti-O固溶体开始脱氧，还原速率变得很低。