Steel slag is a by-product of iron and steel production by the metallurgical industries. Annually, 21 million tons of steel slag is produced in the just United States. While a substantial amount of steel slag is utilized especially in the construction industry, most of the annual inventory of steel slag is landfilled, which represents a significant economic loss and a waste of valuable land space. Even more important, landfilling steel slag enables its acute alkalinity to adversely enhances the leachability of the heavy metals contained in steel slag.

Steel slag is produced from Basic Oxygen Furnace and Electric Arc Furnace in steel making and the main chemical compositions include CaO, SiO2, Al2O3, Fe2O3, MgO and FeO. Beyond the leaching of toxic heavy metals from steel slag, its various applications and sometimes, expose communities to its dust, which equally have very harmful effects especially for children.

Sas, Wojciech et al. “Environmental and Geotechnical Assessment of the Steel Slags as a Material for Road Structure.” Materials (Basel, Switzerland) vol. 8,8 4857-4875. 30 Jul. 2015, doi:10.3390/ma8084857