Industrial irreplaceability and China’s refining node power in critical mineral networks

China occupies a pivotal position in contemporary critical mineral refining, yet its predominance does not translate into uniform leverage. Using document-based comparative process tracing and a structured cross-case comparison of lithium, cobalt, rare earths, and nickel, the article examines when concentrated conversion capacity becomes politically usable. It argues that concentration is only a screening condition: refining node power emerges when conversion capacity creates industrial irreplaceability, vulnerability can be activated through a coordinated execution chain, and upstream or downstream gatekeepers leave effective control within the refining network. The comparison identifies strong node power in rare earths, anticipatory effects in lithium, fragile effects in cobalt, and segmented effects in nickel. Process specificity, qualification cycles, compliance requirements, and countervailing gatekeepers shape the political effects of midstream concentration. Conceptually, the article disaggregates hub centrality into industrial irreplaceability, execution, and countervailing gatekeeping, showing why supplier shares are an unreliable proxy for usable influence. Empirically, it maps how midstream power operates through material conversion, qualification, and market eligibility. The findings shift critical mineral analysis from nominal concentration to the institutional and industrial conditions that make dependence politically usable and offer a grounded account of midstream power in the contemporary regional political economy of decarbonization.