[ Sustainability ]
[ Sustainability ]
Introduction It is an enormous challenge : how to reduce the carbon footprint of steel and stainless-steel mills ? Astonishingly , producing stainless steel on average generates seven times its weight in CO 2 emissions . What can be done ? The last three years have seen a marked increase in decarbonization initiatives , mostly in Europe and Asia , both in carbon- and stainlesssteel mills . European stainless steel producers and fabricators such as Alleima , Aperam , Mannesmann Stainless Tubes and Outokumpu are closely examining their carbon footprint , decarbonizing their energy supply and intensifying their recycling activities . Outokumpu and Aperam have launched sustainable products with near-zero footprint and have stepped up the re-use of scrap . Europe ’ s most active player is Outukumpu , which has undertaken to reach zero CO 2 emissions by 2050 , though it aims to get there much sooner . Stefan Erdmann , Outokumpu ’ s Chief Technology Officer , tells me that the company generates 0.5 kg of CO 2 to make 1 kg of its Circle Green stainless steel ( depending on the desired grade and alloy composition ) compared with a world average of 7 kg of CO 2 ( data provided by the CRU Group and worldstainless , for 2023 ).
Sustainable stainless Stainless steel has a head start over carbon steel in that it is longer-lasting . This durability is important as it means less metal is consumed , and because mining and refining have a large carbon footprint . Stainless is essentially a “ set and forget ” material , one moreover that does not need painting . Another sustainable feature is the favourable strength-to-weight ratio of many grades , especially duplex , which means less fuel is consumed when it is applied in ships or heavy vehicles , as well as in the handling and transportation of the materials . Stainless steel plays a crucial role in the green transition , as it finds multiple applications in lowand zero-carbon energy ( wind , wave , solar , geothermal , biomass , hydrogen , nuclear ) and decarbonization ( airscrubbing systems in carbon capture and storage ). In water applications , stainless steel ’ s corrosion resistance and inert character make for greater hygiene and fewer leaks , conserving both materials and water . On buildings , stainless steel ’ s reflective capacity allows it to deflect and dissipate heat so that less air conditioning is needed .
3D printing New technologies are supporting sustainability not only in primary manufacture but also in fabrication . 3D printing , which is increasingly being
Nickel and titanium
The nickel and titanium industries face the challenge of adopting more sustainable mining and processing methods . Nickel is processed at very high temperatures , but high-pressure acid leaching offers a less energyintensive alternative . Bioleaching promises to negate the need for higher temperatures altogether . As for titanium , alternatives are being sought to the Kroll method , which requires high temperatures ( 1,300 ° C ) and corrosive chlorides to form the titanium metal sponge . IperionX proposes its Hydrogen Assisted Metallothermic Reduction ( HAMR ) technology , which is simpler , faster and requires lower temperatures , and its Hydrogen Sintering and Phase Transformation ( HSPT ) technology . These replace the traditional refining and forging steps . The pilot phase is complete and commercial production will begin in Virginia 2024 using 100 % Ti metal scrap . Meanwhile , Rio Tinto has started its BlueSmelting demonstration plant at its metallurgical compete in Sorel-Tracy , Quebec , using ilmenite reduction technology that could reduce CO 2 emissions by 95 % compared to conventional coal burning .
BUTTING , a producer of longitudinally welded tubes from coil and sheets , is working with Cronimet Envirotec to recycle materials , waste and cutting residue .
16 Stainless Steel World May 2024 www . stainless-steel-world . net