黒鉛るつぼで溶融したスラグからのカリウム蒸発速度について

抄録

In relation to the alkali recycle in a blast-furnace, the rate of vaporization of potassium from slags was investigated. At temperatures between 1723 and 1923 K and under argon atmosphere, the mass loss from the slag melted in a graphite crucible as a reductant was continuously measured by means of a thermo-balance.
At lower temperatures, the mass loss was due almost to the vaporization of K, but at higher temperatures, particularly in the slags with high concentrations of SiO₂, there was concurrent evolution of K and SiO from the slag. The rate of vaporization was represented by the first-order-type rate equation. The rate constant were in the range from 9.5×10⁻⁸ to 4.6×10⁻⁷ m/s at 1773 K. It was found that the rate constant increased with increasing basicity of blast-furnace-type slags. The apparent activation energy varied from 173 to 314 kJ/mol with slag composition. It was observed that the rate of K vaporization was strongly dependent on the wetting of slag on the graphite crucible wall. The vaporization of K from the slag was controlled by the chemical processes at the slag-graphite interface.