Embedded critical material flow: The case of niobium, the United States, and China

Niobium, often classified as critical, is typically embedded within steels essential for infrastructure and trans-portation. Most niobium-consuming countries are import-dependent on primary stage niobium, meaning tradi-tional material flow analysis, which often excludes critical commodities embedded within products of large-scale industries, would miss important flows in the fabrication and manufacturing stages and underestimate niobium consumption. This study presents the first dynamic (2000-2020) niobium flow analysis for two niobium -consuming, net import-dependent countries: the United States (U.S.) and China. Results demonstrate that the U.S. is import-dependent throughout all stages of the niobium flow cycle including embedded and primary flows, whereas China is only import-dependent on primary niobium. Moreover, while most U.S. imports of niobium embedded within (semi-)finished goods are consumed domestically, most niobium-containing goods manufac-tured in China are exported, suggesting a supply disruption would affect their economies differently. This research demonstrates the necessity of embedded flows for criticality assessments and evaluating supply restrictions.

Automated summary

Niobium, classified as a critical material, plays an essential role in steels for infrastructure and transportation. This study analyzed the flow of niobium in the United States and China, revealing that the U.S. is import-dependent at all stages while China only relies on imports for primary niobium. Additionally, the consumption and export patterns of niobium-containing goods differentiate the impact of potential supply disruptions on the two economies.