Slag (Blast Furnace or Iron Slag)
Slag is the rock left over after a desired metal has been separated from its raw ore. Iron Ore, coke and flux stone are put into a blast furnace and reduced to a molten mass by great heat. Blast Furnace Slag is produced three ways:
1. Air-Cooled Slag – cooled under atmospheric conditions and accelerate by water sprays.
2. Expanded Slag – cooled with controlled quantities of water to produce a lightweight product.
3. Granulated Slag – chilled quickly to form a glassy granular product.
Uses: Slag is used as an aggregate in road base fill, concrete, asphalt, concrete blocks, cement production, rock wool insulation, commercial roofs, railroad ballast, glass production, agricultural lime and silica fertilizer.
Color: Slag can be a range of colors depending on how it is produced, but is mainly white or grey. It can also be different shades of green/blue, and have a smooth glassy texture.
Fun fact! Did you know? Many of the runways and taxiways at the Detroit Metro Airport are built on a slag base and slag is used extensively in the concrete pavement.
