Abstract
Blast furnace slag and steelmaking slag are by-products produced in steel plants and legally approved as slag silicate fertilizers. However, the reliability of their efficacy has been low due to their unstable silicate solubility.
In this study, granulated and air cooled blast furnace slags were compared for chemical and mineral compositions and silicate solubilities, and some possible reasons for the inconsistent efficacy of the fertilizers were discussed. Solubility improvement was examined by treating granulated blast furnace slag with chemical adjustment and recrystallization and investigating the relationship between mineral composition and silicate solubility. It was found that silicate solubility could be significantly improved by adding MgO to granulated blast furnace slag and reheating it at 1,300 or 1,350℃ for recrystallization of merwinite and monticellite.
