The Fourth Chokepoint: Administrative Standardization as Process Control in China's Rare Earth Separation Industry

Earlier work on rare earth supply chain resilience identifies three chokepoints, geology, processing capital expenditure, and separation learning curves. This preprint proposes a fourth, administrative control of the process envelope, meaning who may run a separation cascade, at what volume, on which feed, to which technical reference, under whose data, and with what permission to transfer know-how. Using public records from 2011 to October 2026, it describes six coupled layers of control in China's rare earth sector (volume, structure, technical envelope, information, boundary, and buffer) and maps them onto a process control analogy. Verified findings include the 2024 company level split of mining and separation quotas, the placement of the entire ion-adsorption mining quota in one company, the 2025 shift to undisclosed quotas and total volume control, and the concentration of imported feed in two border supply lines. The paper audits a broader compilation of reported mechanisms against public sources. Every claim is graded by evidence tier in an appendix, errors are corrected, and unverified items are listed as open requests for verification. The central thesis is presented as a hypothesis with rival explanations and falsifiable predictions, not as an established result. Corrections and primary sources are welcome.