How will tramp elements affect future steel recycling in Europe? – A dynamic material flow model for steel in the EU-28 for the period 1910 to 2050

Abstract Global steel production has undergone massive growth since WWII. In recent decades, however, affluent regions such as the US and the EU-28 have been experiencing a saturation of the steel market. Stagnant steel production volumes and increased post-consumer scrap volumes are the consequence. The increasing shares of post-consumer scrap provide the opportunity to increase the scrap rate (share of utilized scrap) in crude steel production. However, steel recycling has a major limiting factor: the content of specific tramp elements. In the present study, a dynamic material flow model for steel is used to compare available scrap with crude steel demand on a quantitative and qualitative level (tramp element content of Cu, Ni, Mo, Cr and Sn). The results show that post-consumer scrap increases from 80 Mt/yr (65% of all scrap available) in 2020 to more than 100 Mt/yr (75% of all scrap available) in 2050. Based on the model, the development of the yearly surplus of low purity scrap (for which there is a higher supply than demand) was assessed via material pinch analysis. The low purity scrap surplus rises further, from today's 20 Mt/yr (2020) to 43 Mt/yr in 2050. Assuming that the current handling of scrap continues, the maximal scrap rate is shown to lie at around 55%, while the potential scrap rate (without quality constraints) could reach 75%. The dilution of low purity scrap with high purity resources would allow the utilization of all scrap until 2040 if the current collection scheme remains in place.