Scrap Decarbonising Steel and Cement
The RECTIFI project is looking to gain a better understanding of “Scrap” as a vital step in creating a circular economy within the steel, cement, and recycling industries.
The Challenge
The RECTIFI* project brings together the steel, cement, and recycling industries to significantly reduce these carbon emissions.
The steel and cement industries are together responsible for almost a fifth of global carbon emissions. RECTIFI’s ambition is to avoid almost 5 million tonnes of CO2 a year from entering the earth’s atmosphere. The percentage of recycled metal major UK steelmakers can add during steelmaking is limited, due to process technology and contaminating elements in steel scrap.
Our Research
Our objective was to conduct characterisation on melted scrap material to develop our understanding of scrap and to optimise sorting processes to improve the quality of scrap for steelmaking.
Using our vacuum induction melting (VIM) furnace we melted scrap for chemical analysis. We used optical emission spectroscopy to provide an accurate compositional analysis of the melted material. The VIM is unique in that it melts under vacuum which has the benefit of reducing slag formation during the melting process. This allows for a cleaner melting process which gives a better compositional representation of the melted scrap material and prevents key elements of interest from being oxidised and leaving the steel which would make analysis more difficult.
In our Pilot Lab we sorted and characterised 3B scrap to improve our understanding of the scrap material, its sources, and contaminants. We performed extensive sorting and characterisation of scrap material to identify high residual material and determine the percentage of that material within the overall mass of scrap.
Solutions and Results
Our characterisation of scrap identified high residual material undesirable for increased scrap use in steelmaking. We devised methods to effectively identify this material for advanced sorting and separation techniques.
We assessed whether a small sampling method could be used to accurately characterise the bulk material, to reduce cost, time, and energy. We implemented our optimised sorting process and demonstrated the quality of scrap steel can be significantly improved. This has the potential for allowing for larger volumes of steel scrap to be used.
Benefits
Improving scrap quality could allow for higher rates of recycling and reduce reliance and use of raw materials.
Our research will help RECTIFI’s industry partners develop rigorous and objective material specifications for the new recycled material grades. It will provide independently verified, fully transparent bulk materials analysis for those materials.
We also provided life-cycle assessment of the emissions saved during the project.
Industrial Decarbonisation
By-products produced during metal recycling can be utilised to decarbonise the cement industry through the development and use of mineral-rich products as an alternative raw material during the cement production process.
The UK consumes approximately 12 million tonnes of semi-finished steel and generates around 11 million tonnes of recycled steel per year. Currently, 80 percent of this recycled material is exported, with millions of tonnes of virgin iron ore imported in its place.
Our research is helping to identify, implement, and optimise scrap sorting processes to improve the quality of scrap for steelmaking. Better control of residual elements would improve scrap quality which would enable higher recycling rates and reduce the reliance and use of raw materials – a vital step in reducing carbon emissions and creating a circular economy in steelmaking.
Thanks to contributor Luis Escott at Swansea University on the RECTIFI Project.
*RECTIFI stands for Reducing Embedded Carbon Through Transformation of Foundation Industries.