Environment
Arguments for steel, the world champion of recycling
18. July 2018
Arguments for steel, the world champion of recycling
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Volkmar Held
As a freelance writer, Volkmar Held reports for voestalpine on topics that move people. The content of his stories ranges from archaeometallurgy to future technologies.
Its properties and ability to be repeatedly recycled make steel one of the world’s most reusable materials.
Steel, a true multi talent. It can boast a whole series of naturally advantageous properties which make it unique: low cost of production, durability, strength, and flexibility. Another property has becoming increasingly relevant in recent years: the ecological advantages offered by steel due to its infinite recyclability.
1. Steel offers great performance
Compared to other materials, steel emits significantly fewer greenhouse gases during its production. Aluminum, in contrast, releases eight times the level of emissions during the same process. For instance, the comparative average global warming potential (CO2 equivalent per ton of material) during material manufacture is:
- Steel: 2,000–2,500 kg/t
- Aluminum: approx. 16,500 kg/t
- Carbon-fiber-reinforced plastics: 21,000–3,000 kg/t
- Magnesium: 36,000–56,000 kg/t
2. Making new from old
The average service life of a steel product is closely linked to its form of use (see image). (IC) Service life of steel products
Service life of steel products, source: WV-Stahl
Yet even once their service life is over, steel products are far from ready for the scrap heap. They meet all the demands of products in a functioning circular economy, being durable, easy to repair, as well as 100% recyclable. These advantages are summarized as the “4Rs”:
- Reduce: High-strength and ultra high-strength steels reduce the weight of components while offering equal or even improved functionality.
- Reuse: The properties of components made from steel enable them to be repeatedly reused.
- Remanufacture/Repair: Steel components can be repaired using a variety of different processes, or be remanufactured to extend their service life.
- Recycle: Steel can be recycled as often as wished. The material cycle is closed.
In Austrian railway construction, currently around 15% of all turnouts have been remanufactured and then installed. This saves costs as well as new materials, and reduces CO2 emissions. This is a business area in which the voestalpine Railway Systems companies demonstrate their expertise.
3. Scrap: ecologically exemplary
A steel part’s end of life is simultaneously the beginning of its new life as scrap—a valuable raw material. Steel’s infinite recyclability offers considerable ecological advantages, for example by helping to save raw materials and reduce energy consumption. Scrap is also an important aid in the manufacture of crude steel, including via the blast furnace route. When used in the oxygen converter it simultaneously functions as a vital cooling agent in the process, and as a source of iron (at voestalpine it is quite common for scrap to make up as much as 25% or more of the crude steel volume).
According to worldsteel, over 22 billion tons of steel have been recycled since the year 1900.
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Volkmar Held