(478f) Synergistic Metal Recovery and Carbon Mineralization from Mg-Silicate Minerals

This study presents a sustainable method for extracting metals from olivine minerals, addressing climate change and mineral scarcity. Our method employs hydrometallurgical leaching for the selective recovery of Ni²⁺ and the transformation of Mg²⁺ into carbonates, contributing to renewable energy transition and carbon sequestration. We achieved over 90% conversion of Mg²⁺ and Ni²⁺ into high purity carbonates by controlling the operational conditions of a stepwise process. We explored various inorganic/organic acids for leaching, optimizing pH levels and extracting Fe separately to obtain pure Fe salts and silica through solvent extraction and pH swing, which significantly minimizes metal loss by preventing co-precipitation reaction of silicon and iron. The techno-economic analysis confirmed that separating iron extraction increases the ecumenic impact of products. After purifying the leachate by eliminating impurities such as Fe and Si, we employed Versatic 10 to selectively separate Ni²⁺, using either strong acids or environmentally friendly agents like CO₂ for efficient Ni²⁺ extraction. Subsequently, these ions recovered with CO₂ bubbling were converted into NiCO₃ through carbonation. This proposed process not only purifies the leachate, but also converts Mg into different polymorphic Mg-carbonate under ambient conditions through carbon mineralization. Our findings demonstrate effectiveness of our approach in carbon capture and utilization, and converting metals into valuable commercial products, promoting a comprehensive approach for environmental and resource management.