Trash or treasure? Sustainable noble metal recovery

Abstract

The noble metals, owing to their unique properties, find extensive applications in various modern industries. However, as non-renewable resources, the reserves of noble metals in the natural environment are limited. Therefore, recovering noble metals from discarded industrial waste not only helps alleviate the challenges of noble metal resource scarcity, but also addresses environmental pollution. Herein, the state-of-the-art techniques for noble metal recovery are divided into two categories, pyrometallurgy and hydrometallurgy, in which the conversion mechanisms are discussed. The pyrometallurgy strategies depend primarily on high-temperature smelting reduction, while the hydrometallurgy strategies are segmented into leaching, enrichment and extraction, showing enormous development potential in the future. The novel exploration of noble metal pyrometallurgical extraction is briefly reviewed. The solvolysis, photochemistry, and electrochemistry-initiated approaches for noble metal recycling from secondary resource are summarized in detail. Finally, the future challenges and development prospects of sustainable noble metal recovery are discussed. This work offers a summary of current recovery methods for noble metals and provides a reference for resource utilization.