Slag is the silicon dioxide and metal oxide mixture left over as a by-product of extracting metal from its ore during the smelting process. The term “slag” originally referred to slag produced by metal manufacturing processes, nowadays, it is also used to describe slag that is generated from the recycled metal and scrap-based steel industry. Slag consists of the undesired impurities in the metal ore extracted during the smelting process. Once the metal is smelted to a satisfactory level, the slag is skimmed off the top, or tapped, and can be used for secondary purposes such as manufacturing concrete, fertilizers, or road materials.

Slags are named based on the furnaces from which they are generated, and can broadly be categorized as blast furnace slag, and steel making or metal recovery slag. See Fig 1. The composition and properties of a slag depend on the type of process used to produce it, the cooling conditions of the slag, and processes adopted to possibly enhance the slag.

Fig 1: Types of Iron and Steel Slag

Olive & Branch M&D is a provider of a slag produced in a submerged arc furnace, thus the name SAF Slag. SAF Slag is a granulated slag as a result of the molten slag suddenly being quenched in water upon exiting the furnace. The elemental composition of SAF Slag is somewhat reminiscent of an aluminosilicate material, since the two largest components of the slag are Silicon and Aluminum, almost in equal amounts.

See the SAF Slag product page below to learn more about this one-of-a-kind material.