Binder for Cold Bonded Pellets Made from Reformed LD Slag

Abstract

Slag from LD converter and alumina-sludge from extrusion process of aluminium construction materials have been mixed each other and then melted in MgO crucible in order to reform the slag.
The hydration hardening is observed in this reformed slag. The maximum crushing strength of the reformed slag after hydration is found in the composition of 38.5 wt%CaO-12.8 wt%MgO-9.5 wt%SiO₂-20.0 wt%Al₂O₃-12.2 wt%Fe₂O₃-7.0 wt%MnO. It is estimated by X-ray diffraction analysis of the reformed slags before and after hydration that the hardening is caused by the formation of some crystallized materials from amorphous oxide with composition of probably CaO·MgO·Al₂O₃·SiO₂ which is contained in the reformed slag.
Cold bonded pellets have been made of iron ore using the reformed slag as binder. Crushing strength of the pellet is above 120 kgf/P. The binder made from the reformed slag doesn't affect swelling and reduction rate of the pellets.