Today, environmental factors are at the forefront of material selection for designers and specifiers. Stainless steels long service life (including their low or zero maintenance need), 100 percent recyclability and its valuable raw materials make it an excellent environmental performer.
Stainless steel objects rarely become waste at the end of their useful life. Recycled stainless objects are systematically separated and recovered to go back into the production process through recycling.
As well as iron, stainless steel contains valuable raw materials like chromium, nickel and molybdenum which makes recycling stainless steel both economically and environmentally viable. Stainless steels produced with more than 60% recycled content offer the lowest greenhouse gas emissions profile over their total service life of any man-made materials and avoid the need to use toxic coatings to prevent corrosion or material degradation. (Data source; ISSF, Stainless Steels and CO2, Industry Emissions and Related Data, January 2022)
Stainless steel is actively recycled on a large scale around the world by recyclers who collect and process scrap (recycled stainless steel) for re-melting all around the world.
The use of stainless steel scrap is fundamental to the steelmaking process. There are two types of scrap (downstream of the production mills) – reclaimed scrap (old scrap) and industrial scrap (new scrap).
Reclaimed scrap includes industrial equipment, tanks, appliances & electronics (including mobile phones, washing machines and refrigerators) and building materials that have reached the end of their service life.
Industrial scrap includes industrial returns or production offcuts from manufacturing by industrial engineering and fabrication sources.
Today, stainless steel manufactured in developed economies is made up of between 60% and 85% recycled content including:
The useful service life of stainless steel products is long so the availability of scrap is dependent on levels of production from decades ago. However modern urban trends associated with changing usage of, for example, appliances and electronic items on a regular basis means that a reasonable proportion (around 10%) of reclaimed scrap becomes available after just 10 years.
Six major usage sectors consume the continually growing demand for stainless steels and currently comprise;
(Data source; Team Stainless, KIT Stainless Stocks and Flows Study 2022)
Specialised expertise and sophisticated technology is needed in recycling to separate and prepare each type of alloy for re melting.
A recycling processor feeds the scrap into a large shredder to break it into smaller pieces.
It is then chemically analysed and stored by type.
This process may include ‘blending’ the scrap into Chromium-only steels, Chromium-Nickel steels, Chromium-Nickel-Molybdenum steels, Nickel alloys and other types of stainless steels.
After blending into piles for specific customer requirements the scrap is then loaded into containers for export to overseas mills.
Scrap along with other processed raw materials, Ferrochromium (Fe+Cr), Ferronickel (Fe+Ni) Ferromolybdenum (Fe+Mo) and sometimes pure Nickel are blended and charged into an electric melting furnace.
During melting, impurities are driven into the floating molten slag (which is subsequently decanted and turned into roadstone), the molten metal is refined, and the chemistry analysed to determine what final adjustments are necessary for the specific type of stainless steel being produced.
The molten stainless steel is then generally continuously cast into slabs, blooms or billets before production of plate, sheet, coil, bars, wire and other forms in preparation for use by industrial and domestic products manufacturers.
Domestic manufacturers produce stainless steel items that you use every day including appliances, cutlery, pots and pans and kitchen sinks. Industrial manufacturers generally produce many architectural, construction and industrial components and associated fixing products.
At each stage of the production and use process, stainless steel retains its basic properties and utility value. Unlike many industrial and engineering materials, stainless steel may be repeatedly returned to its original quality in the supply chain without any degradation.
You can be assured that even after its long service life, your environmentally efficient stainless steel will always return to you bright, shining and new!