Research and Development of Continuous Production of Titanium from the Oxide by means of Combination of Calciothermic Reduction and Electrolysis in Molten Calcium Chloride

建立了一种由钛的氧化物直接制取金属钛的新工艺。在传统的Kroll工艺中，这不使用任何瞬态化合物如TiCl_4。该方法包括（A）通过溶解在熔融盐中的钙进行的钙热还原，和（B）副产物CaO的电解。本文分别进行了大规模氯化钙熔盐钙热还原和CaO熔盐电解生产循环用钙的基础实验（A）和（B），以确定钙的产率、杂质、离子迁移热对流、合适的坩埚材料和电极间距。随后，计划将（A）和（B）的组合用于大规模的连续生产，并构建用于确认。在所谓的OS工艺（A）+（B）中，阳极放出的CO/CO_2气体中的碳会污染钛。但用ZrO_2固体电解质膜可消除这种污染。OS法可直接从Nb、Ta、V、Zr、Cr的氧化物中制取Nb、Ta、V、Zr、Cr等金属，是一种节能的工业生产新方法。

A new process is established to produce metallic titanium from its oxide directly. This does not use any transient, compound such as TiCl_4 in the conventional Kroll process. This process consists of (A) calciothermic reduction by calcium dissolved in molten salt, and of (B) electrolysis of the by-product CaO. Combination of these two elemental steps into a single bath was confirmed experimentally as an industrial applicable process.Two fundamental experiments, (A) calciothermic reduction in large scale molten calcium chloride and (B) molten salt electrolysis of CaO to produce Ca for recycling, were conducted separately in order to find the yield, impurities, ionic transfer thermal convection, suitable crucible materials, and space arrangement of electrodes. Successively the combination of (A) and (B) was planed for continuous production in large scale, and constructed for confirmation.Titanium containing only 500 ppm oxygen could be formed in (A), which arrived at the equilibrium. In so-called OS process, (A)+(B), the obtained titanium was contaminated with carbon which was introduced from the evolved gas, CO/CO_2,at the anode. This contamination was, however, removed by using the membrane of ZrO_2 solid electrolyte. OS process could be applied for production of Nb, Ta, V, Zr and Cr directly from their oxides, and this was proposed as a new production method applicable in the industry for energy-saving.