Abstract
In order to produce metals directly from the oxides, molten CaO-CaCl2 mixture offers a strong reducing environment. CaO in CaCl2 melt electrochemically decomposes into metallic Ca and O2- by applying a certain voltage larger than the theoretical decomposition voltage of CaO. Ca, deposited on cathode and dissolved in the melt, can work as strong reductant. Various metals such as Ti can be produced directly from their stable oxides. Although this calciothermic reduction forms CaO as by-product close to the cathode, CaO dissolves in CaCl2 melt and decomposes again by electrolysis. This OS process could be applied to solid, liquid and gaseous oxides. By applying the sulfides, good quality of metal is realized because they do not form solid solution of sulfur.