Furnace slag, commonly referred to as slag, is a byproduct or waste material produced during the metallurgical processes in the production of iron, steel, and other metal alloys. It is formed when the impurities present in the raw materials, primarily iron ore, coke, and limestone, combine with molten iron and float to the surface. At this stage, the slag is a viscous and molten substance.
Once the molten metal is extracted, the slag is rapidly cooled, usually through contact with water or air, causing it to solidify into various glassy or crystalline particles. These particles can range in size and texture, from fine sand-like granules to larger, angular, or irregular chunks.
Furnace slag possesses several desirable properties that make it valuable for various applications. It is characterized by its high density, hardness, and chemical stability, which makes it suitable for use as an aggregate in the construction industry. The slag is commonly used in making concrete, asphalt, road bases, and railway ballast due to its ability to enhance the strength, durability, and resistance to chemical attacks of these materials.
Furthermore, furnace slag is known for its latent hydraulic properties, which means it can react with water and form compounds that exhibit cementitious properties with time. This property is utilized in the production of supplementary cementitious materials, such as slag cement, which can be used as a partial replacement for Portland cement in concrete production.
In summary, furnace slag is a byproduct of metal production processes, possessing properties useful for construction applications and cement production due to its density, hardness, stability, and latent hydraulic properties.
