The energy transition brings with it a materials transition: Skyrocketing demand for energy critical elements like lithium, nickel and phosphorus will require many new mines to open. Travertine’s proprietary process decouples critical element production from fossil fuel-derived sulfuric acid by electrochemically recycling sulfate wastes, while enabling end-to-end carbon dioxide removal and permanent sequestration in carbonate minerals. Our approach brings chemical circularity to extractive industries, improving environmental outcomes and providing a hedge against future sulfuric acid supply constraints.