Thermodynamic Approach to Evaluate the Criticality of Raw Materials and Its Application through a Material Flow Analysis in Europe

Abstract

SummaryThis paper makes a review of current raw material criticality assessment methodologies and proposes a new approach based on the second law of thermodynamics. This is because conventional methods mostly focus on supply risk and economic importance leaving behind relevant factors, such as the physical quality of substances. The new approach is proposed as an additional dimension for the criticality assessment of raw materials through a variable denoted "thermodynamic rarity," which accounts for the exergy cost required to obtain a mineral commodity from bare rock, using prevailing technology. Accordingly, a given raw material will be thermodynamically rare if it is: (1) currently energy intensive to obtain and (2) scarce in nature. If a given commodity presents a high risk in two of the three dimensions (economic importance, supply risk, and thermodynamic rarity), it is proposed to be critical. As a result, a new critical material list is presented, adding to the 2014 criticality list of the European Commission (EC) Li, Ta, Te, V, and Mo. With this new list and using Sankey diagrams, a material flow analysis has been carried out for Europe (EU-28) for 2014, comparing the results when using tonnage and thermodynamic rarity as units of measure. Through the latter, one can put emphasis on the quality and not only on the quantity of minerals traded and domestically produced in the region, thereby providing a tool for improving resource management.

Vehicles and Critical Raw Materials: A Sustainability Assessment Using Thermodynamic Rarity

“…It should be mentioned that such an exercise would be impossible with other criticality assessments such as the one defined by the European Commission (), based on supply risk or economic importance, since both indicators are dimensionless. This is why Calvo and colleagues () proposed rarity as a new dimension in the criticality assessment of minerals.…”

Raw material criticality assessment as a complement to environmental life cycle assessment: Examining methods for product‐level supply risk assessment

“…The concept of criticality is often framed in terms of “risk” of supply disruption (or “supply risk”) along with some measure of potential (socioeconomic) impacts of supply disruption—often termed “vulnerability to supply disruption” (Erdmann & Graedel, ; Graedel & Reck, ). Some criticality assessments include other dimensions such as environmental implications of primary resource extraction and raw material processing (Bach et al., ; Graedel et al., ; Kolotzek, Helbig, Thorenz, Reller, & Tuma, ; Schneider, ), thermodynamic constraints on resource accessibility (Calvo, Valero, & Valero, ), or social aspects of raw material use (Bach et al., ; Kolotzek et al., ; Schneider, ). In this article, however, we focus on “supply risk” and “vulnerability,” as these are the most common notions of “criticality,” and the main ones operationalized in the GeoPolRisk, ESP, and ESSENZ methods.…”

Exergoecology Assessment of Mineral Exports from Latin America: Beyond a Tonnage Perspective

“…All the ERC values of minerals considered in the current study can be seen in Appendix A, but a complete list of all minerals with their corresponding ERC values can be found in [53]. Table 1.…”

“…Exergy replacement cost of non-fuel mineral for LA-20 in GJ per tonne of element. Source: [53]. Appendix C Table A3.…”