2005 年 46 巻 12 号 p. 2713-2718
To promote the recycling of copper alloy scrap, we developed a new technique for removing Pb from copper alloy scrap containing 2–6 mass% Pb. However, we must evaluate quantitatively the level of environmental impact reduction that can be obtained using this new technology. In this study, a manufacturing system that produces Pb-free copper alloy products using copper alloy scrap was assessed by means of life cycle assessment (LCA). The superiority of the new manufacturing system that uses Pb-free copper alloy scrap over the conventional one that uses virgin materials was investigated from the viewpoint of environmental impact. LCA software (JEMAI-LCA) was used to assess environmental impacts such as global warming, acidification, energy consumption and resource consumption. We assessed the raw material acquisition and casting process of Pb-free copper alloy products. The subsequent processes such as machining, assembling, transportation, use and recycling/waste processing are not taken into account in the environmental impact assessment. The results show that the conversion of the conventional system that uses virgin materials into the new one that uses Pb-free copper alloy scrap decreases the environmental impact, significantly. This is attributed to the nonutilization of virgin materials and the decrease in energy consumption during the casting process.