On Dissolution of Water Vapour in Molten Slags

Abstract

The solubility of hydrogen in a synthetic and basic open hearth steelmaking slags of molten lime-silica-iron oxide system has been determined experimentally.
The hydrogen absorption of these slags is rapid. After the beginning of reaction, the twothirds of the equilibrium hydrogen is absorbed within ten minutes, and only one hour is necessary to reach equilibrium. The solubility of hydrogen in slags is increased in proportion to the square root of the partial pressure of water vapour in the atmosphere with which slag stands in equilibrium, and also is increased with rising reaction temperature. The heat of solution of water vapour into slag is about 13kcal/mol.
The effect of slag basicity on hydrogen solubility is remarkable. In the range CaO/SiO₂ greater than unity, solubility is increased linearly with rising basicity. The solubility reaches the minimum when CaO/SiO₂ is equal to unity, and in the range CaO/SiO₂ less than unity, is increased again with falling CaO/SiO₂. But, when slag contains much amount of iron oxide, the solubility does not increase in the range CaO/SiO₂ less than unity.
Comparing the experimental results of synthetic slag studies with results from industrial heats, a good coincidence has been obtained.