Scrap is the raw material for EAF (Electric Arc Furnace). EAF requires ferrous scrap that will be melted in order to get the liquid steel. Because of its nature, scrap is composed not only by ferrous scrap but also with a great variety of materials: non-ferrous metals (such us stainless steel, cupper, aluminum, zinc, etc.), wooden, plastic and ground.
Even all these materials are not required in the EAF, their effect on final product is very different:
– Non-ferrous materials effects negatively to steel quality. This contamination will require bigger cost in the metallurgy of liquid steel until get the required product. On the other hand, if they are screened and recovered before melting, they have economical value and can be sold.
– Wooden, plastics…these materials, when burnt, they give some energy to the process and they don’t affect to final product quality. On the other hand, they provoke smokes and occasionally COx and/or NOx.
– Ground: this material is very bad for steel making process, as it has not any positive aspect. Opposite to this, it affects negatively to metallurgy, they damage refractories, increase dust emissions, etc. It is a delicate point, because even if it could be considered logic to have some ground in the scrap, it is very common to find out that scrap has an important amount of ground…more than could be considered as logic.