By-products and residues
Gerdau respects the environment and that is why it is looking for intelligent alternatives to re-use by-products generated during the steel production. In addition, to continually reducing the generation of materials that remain from the production process, Gerdau develops studies with support from research entities and universities to increase the use of these materials.
Nowadays, about 80% of the by-products generated are recycling by steelmaking industry or other sectors of economy, such as road pavements, batteries production, cement and ceramic industry. By-products that are not reused are sent to storage centers approved by the environmental authorities, which strictly comply with current laws.
Learn about some of Gerdau´s by-products:
Scale
This material is created by oxidation of the steel’s surface when it comes into contact with the oxygen. It is generated during the casting, forging, and the hot and cold rolling processes. It is predominantly constituted of metal oxides present in the steel’s composition, with the majority of this being iron oxide.
Main applications: Used as a raw material in sintering, in the cement industry, for the production of concrete, and in iron alloys. Some parts of the scale are used to enrich the metallic charge in pig iron and steel furnaces.
Steelmaking Slag
This is a by-product formed by the production of steel at melt shop. It plays an important role in process control and steel quality. It is composed mainly the following oxides: calcium, iron, silicon, magnesium, manganese, aluminum, phosphorus and sulfur.
Main applications: after processing, it is used as aggregate for paving, drainage, rip rap construction, gabions, for the production of concrete tiles and asphaltic mixtures, and as recycled material at the furnace.
Blast Furnace Slag
This is a by-product formed by the production of pig iron in blast furnaces. It is formed by ore gangue, reducing agent ash and fluxes. It is composed mainly the following oxides: calcium, silicon, aluminum, magnesium.
Main application: The material is granulated and used in the production of cement.
Ore Fines
It is a material that results from the handling or screening of iron ore. It appears in the form of fine iron oxide particles.
Main applications: as a raw material for sintering and in the cement production.
Coal and coke fines
These are materials resulting from the handling or screening of coal or coke. This material has a very small grain size.
Main applications: as fuel for re-use in steelworks or other industries.