Boston Metal raised $75 million in 2026 to expand its molten oxide electrolysis process from low-emission steel to niobium, tantalum, chromium and vanadium production, per its May 2026 funding announcement and MIT Technology Review reporting. The company cited rapid deployment in critical metals markets as a means to fund ongoing steel development amid canceled federal grants. Brimstone similarly updated its process outputs to include smelter-grade alumina alongside low-carbon cement following the 2025 DOE cancellation of $1.3 billion in cement project awards. Primary source: https://www.technologyreview.com/2026/05/21/1137622/climate-tech-pivot-critical-minerals/. Related coverage: U.S. Geological Survey Mineral Commodity Summaries 2026 lists niobium and tantalum among materials with high supply risk for aerospace and electronics. A 2025 Reuters report documented multiple carbon removal startups contracting with mining operators for site remediation using electrochemical methods originally developed for emissions reduction.