Electric arc furnace carbon steel slag is a by-product of the manufacture of steel by the electric arc furnace process (EAF).
An Electric arc furnace (EAF) produces steel by the melting of recycled steel scrap, using heat generated by an arc, created by a large electric current Lime added (as flux) combine with silicates and oxides to form liquid slag. EAF slag has a lower density than steel and therefore floats on top of the molten steel. Once the steel has been tapped into a ladle, the slag is either poured from the furnace onto the floor where it is cooled and removed for further processing, or into slag pots where specially designed vehicles are used to transport the slag to purpose-built lagoons. Here it is tipped and cooled prior to onward processing.
Due to the presence of free lime (calcium oxide) and depending on the final end use of the EAF slag, the stockpiles may be weathered for a designated time period in controlled areas. The weathered slag is then tested to ensure the expansion properties of the material as identified in BS EN 1744-1 meet the requirements of its end use.
Compound
Typical Value
Fe2O3
30
CaO
31
SiO2
16
MgO
4
Al2O3
5
Property
Relative Density (SSD)
3.4
Water Absorption
1.0
Magnesium Sulfate Soundness
1
Aggregate Abrasion Value
2.7
Polished Stone Value
63
For further information concerning the standards and specifications applicable to Slag Aggregates refer to the Aggregates page.
For more information contact Mike Wharton.
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