塩酸溶液中の高炉水砕スラグの挙動

抄録

In order to know the behavior of slag (granulated blast furnace slag) in acidic solutions, dissolution experiments of slag in acid solution were carried out using HCl solutions of various concentrations at a solution/slag ratio of 10.0 at 30°C and the changes in the liquid concentration of the components of liquid phase and in the amount of reacted slag during dissolution were determined.
When slag was mixed with HCl solution, slag reacted rapidly as basic material with the solution and the reaction was completed in 1-3 hours. The pH of liquid phase increased rapidly after mixing up and became constant in weak acidic condition in about an hour. The hydration of slag after this reaction was not promoted in acidic solution.
The reaction mechanism of slag with HCl solution was considered as follows.
The GaO and MgO components in slag reacted as basic components preferentially with HCl solution quantitatively and they dissolved into liquid phase as Ca²⁺. and Me²⁺. The decomposition of the slag proceeded by this reaction and SiO₂-Al₂O₃ network structure in the slag was destroyed and SiO₂ ane Al₂O₃ components dissolved into liquid phase. As the solubilities of SiO₂ and Al₂O₃ components in the solution were very low, these components precipitated as SiO₂·nH₂O gel and Al₂O₃·nH₂O gel.