Development of a dynamic model for assessing environmental impact associated with cyclic use of steel

Steels are produced in large quantities and being recycled at high rate in Japan. However, recycling of steel scraps would lead to the enhancement of contamination of undesirable tramp metals in steel scraps. So, the limitation of recycling of the steel scarps would be expected in the near future. This may increase in the production of virgin steels and environmental impacts associated with total steel production in Japan. The authors have developed a dynamic model to assess the maximum recyclable ratio of steel scraps and the total environmental impacts caused by the steel production in Japan. The model is based on population balance model (PBM), material pinch technology in corporate with LCA. The amount of steel scraps generated in Japan and their concentration of tramp metal during 1990-2030 were estimated by PBM. The maximum recyclable ratio of steel scraps in each year was calculated by material pinch technology, in which assessed were optimal balance between the amount and quality of steel scraps and those of steel products. The total CO2 emissions caused by steel production in Japan during 1990-2030 were estimated by LCA.