AEIFOROS S.A. is an industrial by-products- and wastes- recycling company that offers solutions for the valorisation of those materials as secondary resources, raw materials and solid fuels for other industries according to the principles of circular economy promoting industrial symbiosis.
Electric arc furnace (EAF) slag is a byproduct of carbon steel manufacturing and has been used in road construction for many years showing very good performance as asphalt aggregate. Compared to natural aggregates, EAF slag aggregates present a higher density as required in special concrete applications such as heavy concrete for the coating of pipes for offshore pipelines. Concrete weight coating is highly demanding in aggregates of stable quality regarding density and sizing. EAF slag aggregates, as an industrially recovered and processed material, comply with all standards set by the pipeline projects in raw materials specification for the coating mixture.
The processing of the EAF slag for this application comprises intensive water-cooling of the slag directly out of the furnace, successive crushing (at jaw, cone and impact crushers), successive magnetic separation of metallic iron residues, successive screening for the production of certified grain size according to CE standards and factory production quality control. Based on synthesis recipes elaborated by the pipe coating plant, 10,000 tons of EAF slag aggregates are used annually in Greece for heavy concrete pipe coating.
Benefits are two-fold:
- Use of valuable by-products, which in the past were stored on site or landfilled. From the steel manufacturing companies’ point of view, EAF slag is no longer viewed as a waste to be disposed of, but, on the contrary, it is regarded as a profit-generating secondary resource with an industrial added value due to its unique properties. The producer opts to apply sustainable management procedures such as separate waste and by-products storage, quality control procedures, and dedicates human and financial resources for finding markets and promoting the material as it would be done for any other product.
- Saving of natural resources traditionally used in this application: Iron ore and heavy minerals are usually used as heavy concrete aggregates and few sources are available, therefore substituting them even partly with EAF slag aggregates saves valuable natural resources and reduces raw material extraction and landscape alteration, overall ensuring the protection of the environment. In Greece, 10,000 tons of EAF slag aggregates are incorporated annually in concrete weight coating mixtures.
EAF slag aggregates can be combined also with other heavy recovered aggregates leading to the overall substitution of the iron ore or other natural minerals and decreasing the impact value of the pipeline, provided that they are available at reasonable distance from the coating plant.
- The main challenge is the acceptance by the Member State Environmental Authorities that industrial by-products fulfilling the relevant criteria set by the European Waste Framework Directive and satisfying the related “further use” specific technical requirements (e.g. CE label for products included in the Construction Products Regulation) can be indeed regarded as by-products and put on the market as such.
- Projects where industrial by-products are incorporated in the place of natural products e.g. minerals are currently not rated for their environmental footprint according to secondary raw materials used and green procurement principles.
Mrs Anne Surville