Modelling Metals Recycling With a Dynamic Lca Approach: A Methodological Discussion Based on a Real-World Case Study

Modelling metals recycling with a dynamic LCA approach: a methodological discussion based on a real-world case study Federico Rossi1,2, Francesca Albano2, Fabio Iraldo2,1, Monia Niero1,2 1Sant’Anna School of Advanced Studies, Interdisciplinary Center for Sustainability and Climate, Pisa, Italia 2Sant’Anna School of Advanced Studies, Institute of Management, SUM (Sustainability Management) Lab, Pisa, Italia May 14th 2025 Introduction - the ALCHIMIA project The mission of the ALCHIMIA project (Project 101070046) is to provide sustainable and competitive metalworking industries in the EU with a platform to support the transition to highquality, competitive, efficient, and green production processes with the guarantee of high-quality products in the steel-making industry. Baseline calculation Process optimization Comparison Role of LCA Introduction - full life cycle of secondary steel Further processing Use phase Disposal Scraps Recycling Recycling Recycling Waste Collection Secondary steel production Dust Slags Van der Harst, E., J. Potting, and C. Kroeze. 2016. Comparison of different methods to include recycling in LCAs of aluminium cans and disposable polystyrene cups. Waste Management (New York, N.Y.) 48: 565–583. http://www.ncbi.nlm.nih.gov/pubmed/26440926. O2, CH4 Electricity Scraps + Anthracite Dolomite CaO Graphite + Other materials Electricity Water Steel Waste and emissions Input flows materials Output flows Emissions Reference product Slags Dusts Electric Arc Furnace Casting Waste and Emissions Functional unit: 1 kg of steel output from the casting phase System boundaries: cradle to grave (also cradle to gate with options) Background database: Ecoinvent 3.9.1 Software: SimaPro 9.6 LCIA methods: Environmental Footprint 3.1 What is the most suitable LCA modelling approach to evaluate scraps recycling ? •Burden free to valorise the use of scraps in the EAF (cut-off) •Burden of the embodied material, avoided burdens to valorise recycling at end of life (substitution). Research question Argon Electricity Ladle furnace Tapping additions Transport and cleaning Waste and Direct Emissions Internal Return Input flows energy Output flows Coproducts Secondary steel production 1. The Life Cycle Inventory (LCI) varies dynamically heat-by-heat (approximately 500 heats are considered) 2. A dynamic approach for LCA and a statistical evaluation of the impact categories allows to evaluate the variability of the results 3. The results depend on the LCA modelling approach to evaluate scraps recycling The interpretation of the results variability will support us in deciding what is the most suitable LCA modelling approach for scraps recycling Heat number Concentration Methodology Steel grade A Steel grade B Steel grade C Steel grade D 8 steel grades under consideration … Substitution Recycling Disposal Waste Collection Secondary steel production Recycling Recycling Valorizing recycling at end of life Dust Slags Scraps Van der Harst, E., J. Potting, and C. Kroeze. 2016. Comparison of different methods to include recycling in LCAs of aluminium cans and disposable polystyrene cups. Waste Management (New York, N.Y.) 48: 565–583. http://www.ncbi.nlm.nih.gov/pubmed/26440926. Recycling Recycling Disposal Waste Collection Secondary steel production Recycling Valorizing the use of waste as input Cut-off Dust Slags Scraps Harst, E. van der, J. Potting, and C. Kroeze. 2016. Comparison of different methods to include recycling in LCAs of aluminium cans and disposable polystyrene cups. Waste Management (New York, N.Y.) 48: 565–583. http://www.ncbi.nlm.nih.gov/pubmed/26440926. Most relevant impact categories defined by Santero and Hendry (2016) Santero, N., Hendry, J., 2016. Harmonization of LCA methodologies for the metal and mining industry. Int J Life Cycle Assess 21, 1543–1553. https://doi.org/10.1007/s11367015-1022-4 Results - Acidification Acidification mol H+ eq / kg 1.00E-03 2.00E-03 3.00E-03 4.00E-03 5.00E-03 6.00E-03 7.00E-03 8.00E-03 mol H+ eq / kg 1.00E-03 2.00E-03 3.00E-03 4.00E-03 5.00E-03 6.00E-03 7.00E-03 8.00E-03 A B C D H M S U Steel grade A B C D H M S U Steel grade Substitution Cut-off Santero, N., Hendry, J., 2016. Harmonization of LCA methodologies for the metal and mining industry. Int J Life Cycle Assess 21, 1543–1553. https://doi.org/10.1007/s11367015-1022-4 Results - Climate change Climate change A B C D H M S U Steel grade A B C D H M S U Steel grade kg CO2 eq / kg 1.00E-01 2.00E-01 3.00E-01 4.00E-01 5.00E-01 6.00E-01 7.00E-01 kg CO2 eq / kg 1.00E-01 2.00E-01 3.00E-01 4.00E-01 5.00E-01 6.00E-01 7.00E-01 Substitution Cut-off