“Slag sand” is produced after fine wet processing of electric arc furnace slag from stainless steel production (EAF S) and secondary metallurgical slag (SECS), but all other slag types could be used. This high tech method of processing slag allows for utilization of slag that could not be valorised with traditional processing.
The mineral aggregate is calcium-silicate material with approximately 50 % of the particles below 75 μm. The wet processing of slag works in a closed loop system and is environmentally friendly. Metal from the process is returned to stainless steel manufactures in either loose or briquetted form.
The mineral aggregate is used in a number of commercial applications:
- Agriculture - pH adjustment and plant available silicon
- Acid mine drainage prevention, treatment and remediation
- Soil stabilization and road base reclamation
- Road base and sub-base
- General construction engineered fill, embankment, and backfill
- Sludge solidification and stabilization
- Hazardous waste stabilization
- Flowable fill and excavatable backfill
- Cement and concrete
Both the metal and mineral composition of the aggregate provide environmental benefits which include:
- Enhanced crop yields, with reduced fertilizer and pesticide requirements in agricultural applications
- Replacement of natural resources and associated damage to the environment
- Significantly lowered CO2 emissions in steel making, construction and other applications
- Nontoxic aggregate due to low leaching characteristics
Beyond Europe, new fields of applications with good environmental returns are currently being developed. They include:
- Development of new materials for restoring seaweed beds and
- Marine fertilizer products to restore sea desertification areas.
Currently used in some countries is a scientific, safe and environmentally friendly method for the transplantation of corals using slag. Slag is utilised as a major part of the the protection of the existing reefs, the process of restoration and building new artificial reefs. It has achieved the challenge of reducing costs involved in rebuilding/creating a reef to populate a lifeless area.