A review of malachite flotation: Advanced reagents and sustainable practices
Junhyun Choi
Abstract
• Overview of conventional flotation methods and their limitations in malachite beneficiation. • The use of advanced techniques improves flotation efficiency and sustainability. • Emerging eco-friendly approaches like bioflotation and nanoparticle-based collectors. • Comparison of traditional vs. advanced methods in selectivity and environmental impact. • Research gaps and future directions in reagent optimization and sustainability. Malachite (CuCO 3 Cu(OH) 2 ), a copper (Cu)-bearing mineral, is essential for meeting the growing global demand for Cu, which plays a pivotal role in renewable energy systems, electric vehicles, and infrastructure. Efficient beneficiation of malachite is crucial for maximizing recovery and ensuring sustainability. However, the conventional flotation methods face challenges in terms of efficiency, reagent consumption, and environmental friendless. This review traces the evolution of malachite flotation from traditional sulphidization-xanthate flotation methods to more advanced, sustainable flotation techniques. Conventional methods, using sodium sulfide (Na 2 S) and xanthate collectors, suffer from incomplete sulphidization, low flotation efficiency, and significant environmental concerns. In contrast, direct flotation methods using reagents such as sodium oleate, hydroxamic acid, and phosphinic acid enhance flotation by increasing malachite’s hydrophobicity, though they are hindered by high reagent consumption and poor selectivity. Recent advancements include the use of electrolyte-assisted sulphidization, mixed collector systems, and bioflotation, which offer improvements in flotation efficiency, selectivity, and sustainability. Furthermore, nanoparticle-based collectors and depletion interaction techniques represent promising eco-friendly alternatives, improving flotation performance by enhancing bubble-particle attachment. This review critically compares these conventional, advanced, and emerging methods, highlighting their effectiveness and potential for future development, while also identifying research gaps and providing recommendations for integrating sustainable reagents and scaling these methods to industrial applications.