Substance flow analysis of chromium and nickel in the material flow of stainless steel in Japan

This paper dynamically analyzes the Japanese material flow of stainless steel. The substance flow analysis of Cr and Ni associated with stainless steel was conducted by classifying the material flow of stainless steel into two main alloy types: ferritic and austenitic. The substance flow covered more than 80% of Cr and Ni consumption in Japan. In mass balances of Cr and Ni, the production of not only stainless steel but also other alloying steels containing Cr and/or Ni was taken into account. The mass balances of three elements (Fe, Cr, and Ni) provided complementary information for confirmation of our estimations. As a result of dynamic analysis, the in-use stock of ferritics and austenitics at the end of the year 2005 was 4 Tg and 14 Tg, respectively, which converts to 3 Tg of Cr and 1 Tg of Ni. In addition, the recycling flow was closely analyzed. From the result for the year 2005, the recycling rates as stainless steel scrap were estimated as 21-38% for ferritics and 94-100% for austenitics. The amount of ferritics scrap to be recycled as carbon steel was quantified as well. By comparing our results with those in previous studies, we found that applying parameters obtained in other countries may be misleading, especially in recycling flows. (C) 2010 Elsevier B.V. All rights reserved.