A MACRO MODEL FOR STEEL USAGE PATTERN IN JAPAN USING A POPULATION BALANCE MODEL

A macro model for the steel usage pattern in Japan is proposed, clarifying the dynamics of steel types based on manufacturing methods and their recycling processes. The objective of this study is to develop a model that accounts for multiple factors influencing the steel recycling process, particularly focusing on the impact of copper contamination. Methodologically, the research employs a population balance model to calculate the amount of electric furnace (EF) steel and its accumulation in society over time. This is achieved by analyzing the lifetime distributions of various steel usages and comparing the model's outputs with existing statistical data, which validates its efficacy. Results indicate a trend toward increased EF steel for construction, leading to potential oversupply; consequently, the demand for EF steel for machinery necessitates considerations of allowable copper concentrations to mitigate contamination risks. The study predicts copper concentrations in EF steel across various scenarios, emphasizing the need for improved management of recycling processes to enhance the quality of recycled steel. This research contributes valuable insights into the sustainability of steel usage and recycling practices in Japan.