Secondary aggregates

Steel Slag

This is a by-product of the steel manufacturing process.The molten slag, which sits on top of the molten steel during manufacture due to its lower density, is tapped off into a cooling pit. Here the molten slag is air cooled, producing an aggregate which can be processed into the required size fractions to be used in construction applications such as asphalt and concrete materials.

Blastfurnace Slag

A by-product of the iron manufacturing process. The molten slag, which sits on top of the molten iron during manufacture due to its lower density, is tapped off into a cooling pit. Here the molten slag is air cooled, producing an aggregate which can be processed into the required size fractions to be used in construction applications such as asphalt and concrete materials.

Alternatively the molten slag can be quenched by ambient water, at a ratio of 1 ton molten slag: 8-10 tonnes of ambient water, this cause's thermal shock producing a Granulated Blastfurnace Slag (GBS) material which can be further ground to produce Ground Granulated Blastfurnace Slag (GGBS) which has cementitious properties and is commonly used as a cement replacement in concrete.