抄録
The macro model for analysis of the steel mass flow in Japan is proposed and the problems for realizing the environmentally sustainable society are analyzed. In the model, the steels are classified into four types; converter steel for machinery, converter steel for construction, electric furnace (EF) steel for machinery and EF steel for construction and they are assumed to be discharged from the society in accordance with lifetime distributions. The promotion of recycling increases the production of EF steel and its impurity concentration. Consequently, the amount of the EF steel supplied for machinery use is limited by the increase of copper concentration and it becomes necessity to reduce the copper contamination in post-consumer scraps in order to promote recycling. The goal contamination ratio is estimated from the calculation result on the scenario in which recycling ratio is assumed to be 100%. The reduction amount of CO2 emission by introducing the new technology to reduce copper contamination is calculated and it is converted to the cost assuming the CO2 international emission trading, which could be invested to the development of the new technology. It is shown that the investable cost is in the range from 8.3 to 30 billion yens par year.
