Kyoto University (KU), Japan, Interested in the effective utilization of an indicator, Total Material Requirement, TMR. The TMR provides a measure of the physical inputs in mass required to produce a material from a given resource using a given process, including upstream inputs, in terms of primary materials including so-called hidden flow such as tailings, gangue, and waste rock, etc. Recently KU redefined two types of TMR. The first type is the TMR to obtain a material from a natural ore (natural ore TMR; NO-TMR), which is in keeping with the original definition of TMR. The other type is the TMR to recycle the material from an urban ore defined as end-of-life products or waste (urban ore TMR; UO-TMR). Recently KU has estimated TMRs for more than 400 products like not only metallic materials but also non-metals, acid/base, other chemical compounds, fertilizer, and foods etc. N-based materials and products such as fertilizer, nitric acid and ammonia are included. KU consider that further estimation and analysis must contribute to the problem solving for N-related issues.
