Abstract
In this study, the total materials requirement (TMR) to recycle chemical elements from the urban ore by recycling (urban ore TMR, UO-TMR) has been compared with the TMR to extract the element from the natural ore by smelting (natural ore TMR, NO-TMR) in order to evaluate the urban ore grade on an equal footing with the natural ore. A framework of UO-TMR based on the NO-TMR framework is developed. To validate the developed framework, the UO-TMR of a laptop PC is estimated assuming gold, silver, copper, iron, aluminum, tantalum and indium are recycled. It is found that the UO-TMRs for gold, silver, copper, iron, aluminum and tantalum are lower than NO-TMR, but that for indium is higher. The ratio of “urban tailings” is at most 60% of the total, which is smaller than that of NO-TMR “tailings”. In contrast to the contributions of energy and material inputs for the recycling process, the contribution of transportation is not very large. For the UO-TMR of indium, the contribution of materials for recycling process is extremely large. The availability and scalability of UO-TMR are also discussed.
