Microstructure and Hardness of Artificial Stones Obtained by Solidifying Reduced Slag in Slag Pot

Abstract

  The development of practical applications for slag is an important challenge. When reduced slag is cooled, it solidifies into a rock-form strong artificial stone. In this study, the minerals and structures responsible for the hardness of artificial stones obtained by solidifying reduced slag in a slag pot in an electric-furnace general steel production line were investigated in detail. Reduced slag from an actual operating line was used in the experiment. The main mineral components of the artificial stone were found to be CaO, Al₂O₃ and SiO₂. The center region of the stone was denser than the outer region and had cavities and small porosity. On the other hand, the outer region had high porosity. The main mineral phase consisted of gehlenite (2CaO·Al₂O₃·SiO₂), with many fine spinel (MgAl₂O₄) crystallites also being present. The artificial stone had a Mohs hardness of 6.5. The formation of gehlenite is considerable to be the main reason for the granite-level strength of artificial stones.