Application of Life Cycle Assessment to Manufacturing of Nonferrous Metals

Life cycle assessment (LCA) is a broad topic that is currently being discussed. However, little is known about the assessment method of environmental impacts expressing a single index, especially in Japan.Non ferrous metals are one of the basic materials for industrial products. The establishment of the assessment for these materials is important to improve the quality of LCA for products.We have proposed a method of assessment for total impact in Japan, and a case study of LCA is performed concerning the nonferrous metals in this paper. The stages considered in this LCA study are: goal and scope of the inventory analysis and impact assessment. The inventory data include the consumption of raw materials and the emissions through the mining, transport and manufacturing. Resource depletion, global warming, acidification, eutrophication and air pollution have been considered as impact categories.The main results of this study are summarized as follows,(1) The impacts of eutrophication, air pollution and resource depletion are serious for the production of aluminum.(2) The stages of the consumption of non oil and that of the production of non oil are serious for the production of zinc, because the large quantity of non oil such as cokes are consumed.(3) We have showed that the interpretation will differ if the criteria of materials for assessment are changed from weight (per kg) to tensile strength (per MN).