Ultramafic Tailings Leaching and Lateritization with Electrolytic Acid Recycling for Critical Metal Recovery and Enhanced Mineral Carbonation

Ultramafic rocks host two resources that are key to avoiding catastrophic climate warming: (1) elements essential for mineral carbonation with gigatonne-scale carbon dioxide removal and sequestration (CDRS) potential, and (2) first-row transition elements including nickel and cobalt that are critical for the renewable energy transition. These elements are chemically bound within solid mineral phases in the rock; Unlocking them to satisfy our urgent needs for CDRS and decarbonization of US energy infrastructure requires a dramatic acceleration of chemical weathering. Our concept implements a pilot of a transformational process that combines strong acid-enhanced weathering and critical metal concentration and recovery in ultramafic mine tailings with a bench-scale verified process for electrolytic acid and base production for sulfuric acid recycling with mineral carbonation, using carbon dioxide from air (patent pending). The proposed process meets the program objectives of turning US mining waste into a valuable resource for both enhanced critical metal recovery and permanent carbon dioxide sequestration using heap-leaching of existing and future tailings, with chemicals that are efficiently produced and recycled using renewable electricity. Electrolytic chemical recycling offers major environmental co-benefits by avoiding huge amounts of chemical waste.