溶鉄中へのガス底吹きによる吸窒・脱窒速度

概要

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Argon and/or nitrogen was injected into molten pig iron through the bottom orifice. The experimental conditions are as follows : gas flow rate, 10-25 Nl/min ; melt depth, 9-28 cm ; temperature, 1400-1600℃. The absorption rate from pure nitrogen was controlled by the mass transfer in metal phase. When Ar-N_2 gas mixture was injected, however, the absorption rate was controlled by the mass transfer in gas phase. The desorption rate of nitrogen by pure argon was controlled by the gaseous mass transfer. The volumetric rate constant, which is defined as the mass transfer coefficient multiplied by the total interfacial area between bubbles and molten iron, was obtained in different conditions. The rate constant for the gaseous mass transfer, Ak_g, increased linearly with the gas flow rate and the melt depth. The apparent activation energy was 64 kcal/mol. The rate constant for the mass transfer in metal phase, Ak_m, increased proportionally to 0.65 power of the gas flow rate, and linearly with the melt depth. The apparent activation energy was 43 kcal/mol. Ak_m/H obtained in the present work was compared with the published data, including not only those of nitrogen transfer, but also of oxygen transfer between bubbles and molten copper and silver.
社団法人日本鉄鋼協会の論文
1987-04-01