open access

https://hdl.handle.net/2115/50310

Direct Metal Production from Oxides by Using Molten Salt Electrolysis of CaO in CaCl2

英語

2009

日本学術振興会 加工プロセスによる材料新機能発現第176委員会

Proceedings of Processing and Fabrication of Advanced Materials XVIII

2

701-710

Molten salt electrolysis of CaO dissolved in the CaCl2 melt can generate the reactive Ca atmosphere near the cathode, which has a strong reducing ability equivalent with pure Ca. When the oxide is set inside the basket-type cathode, it is reduced to the corresponding metal. The applied voltage should be controlled between 1.6 and 3.2 V above the melting temperature of CaCl2 (1053K), when a carbon anode is used. The formed by-product CaO is removed as CO and C02 gas at the carbon anode. Within 3 hours we can obtain pure α-Ti from the starting Ti02 powder in CaCl2-O.5mol%CaO melt. As increasing the supplied charge, the residual oxygen in Ti decreased. This simple mechanism has been successfully applied for production of 12 kinds of metals such as Ti, Zr, V, Nb, Cr, Fe, etc. However, the rare earth metals such as Y and Er could not be obtained due to thermodynamic limitation of calciothermic reduction. MgO, In203 and Sn02 formed their metallic liquid.

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