マ ッ ト の 酸 素 富 化 溶 錬 の 熱 力 学

抄録

For thermodynamically understanding copper or nickel smelting processes using oxygen or oxygen-enriched air as a blowing gas, a series of the authors' experimental studies of the phase equilibrium and distribution of minor elements between the copper matte or the nickel matte and the FeOX-SiO2 base slag under the SO2 partial pressures of 0.1, 0.5 and 1 atm at 1,300 °C are reviewed in this paper. The solubility of copper was found to be independent of pSO2 when the matte grade was specified and it was considered that this behavior was ascribable to the constancy of (pO2 /pS2 ) against pSO2 . On the other hand, it was clarified that the solubility of nickel in the slag increased with increasing pSO2 at a given matte grade. The difference in the dissolution behavior between copper and nickel was considered to be ascribable to the difference in the chemical formulas of the mono-metallic sulfides in which one copper atom combines with 1/2 sulfur atom while one nickel atom with 2/3 sulfur atom. When the distribution ratio of a minor element, X, between the slag and matte phases was defined as LXs/m = (mass % X in slag)/{mass % X in matte}, LXs/m for arsenic, antimony and bismuth at a given matte grade increased with increasing pSO2. This behavior was explained reasonabley by assuming a mutual reaction between a metallic species in the matte and an oxidic species in the slag. On the other hand, the distribution ratio of silver at a given matte grade was almost constant against pSO2. This was considered to be ascribed to the sulfidic species of AgS0.5 prevailing in the matte phase as well as the constancy of (pO2 /pS2 ) against pSO2.