CaO-SiO2-TiO2系の電気伝導度と酸化チタンの挙動
酸化チタンを含む溶融スラグの電気伝導度-IV
1960 年 46 巻 2 号 p. 134-140
詳細
1960 年 46 巻 2 号 p. 134-140
In order to study the behaviour of titanium-oxide in molten slags and to obtain some informations concerning the electric-smelting of titaniferous iron sand, the electrical conductivity of the CaO-SiO2-TiO2 system was measured in the temperature range 1470-1200°C. The one electrode and the crucible, which itself functioned as theother electrode, were made of platinum. The measured ranges of compositions were CaO/SiO2 0·67-1·22 at TiO2 19·5mol%, CaO/SiO2 0·70-1·28 at TiO2 30mol% and TiO2 24·6-46·0mol% at CaO/SiO2=1.
The specific electrical conductivity was of the order of 0·1-1Ω-1cm-1, while the activation energy of conduction was 25-30kcal/g-mol. It was presumed that the conduction mechanism was ionic and the mobile ion was Ca2+.
At a constant TiO2 concentration the specific electrical conductivity was increased with CaO/SiO2, but the conductivity (μ) equivalent to one grammole of CaO had a maximum at near CaO/Sio2 =1·1.
At CaO/SiO2=1 the conductivity was increased with the increase of TiO2 content. This could be ascribed to the fact that Ti ion strogly weakend Si-O network owing to the coordination number of six and the comparatively strong Ti-O bond. It was in this respect that TiO2 had a behaviour different from that of Al203 or SiO2 whose coordination number was four and which was able to form network.
Furthermore, it was presumed that if any small quantities of FeO and Ti203 were contained in the CaO-SiO2-TiO2 slag as in the practice of the titaniferous iron sand smelting, the electrical conductivity would be increased more sharply with the increase of the titaniumoxide content owing to the semi-conductive behaviour of titanium-Oxide. This fact had great significances in the practical operation of an electric smelting furnace.
