Assessment of secondary zinc reserves of nations

When addressing the sustainable use of metals, one must consider not only primary metals in the natural environment but also alternative resources, such as secondary metals found in society. For that purpose, elucidating the availability of secondary metals, that is, secondary metal reserves, is important. A classification framework of the secondary resources was applied to investigate its applicability to zinc and to assess the secondary zinc reserves and resources of major targeted countries. Our estimates show that Japan and the United States have secondary zinc reserves of 14 and 13 Mt, respectively, and showed the total estimated amount of secondary zinc reserves of the study countries is equivalent to about 24% of the global primary zinc reserves. On a per‐capita basis, France, Germany, and Japan have the largest secondary zinc reserves. The application of a classification framework showed that a considerable amount of secondary zinc resources is found in landfills, providing a future potential target for secondary zinc landfill mining. The framework provides details about the sizes and locations of secondary zinc resources. This information is useful for both industry and policy makers to maximize access to valuable secondary zinc sources. This study also highlights the necessity for the integrated management of primaszzry and secondary zinc resources.