Graphene surface grafting with sodium oleate via plasma treatment to enhance fine-grained quartz flotation performance

• Cold plasma grafting NaOL chains create high-density hydrophobic zones on graphene. • PG-GOS enhances quartz recovery by 30% versus NaOL. • Mesh structure of PG-GOS aggregates fine quartz particles via network capture. Efficient quartz recovery is essential for the sustainable utilization of mineral resources. This study presents a green composite flocculation collector, sodium oleate-grafted graphene (PG-GOS), synthesized by covalently grafting sodium oleate onto a graphene oxide framework. This nanomaterial serves a dual purpose: flocculation and collection. Comprehensive characterization techniques, including Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis, micro-flotation tests, and scanning electron microscopy/X-ray photoelectron spectroscopy (SEM/XPS), demonstrated that PG-GOS aggregates fine quartz particles (less than 38 μm) into clusters ranging from 50 to 200 μm, significantly enhancing their floatability. Quartz recovery improved by nearly 30% compared to systems utilizing standalone sodium oleate (NaOL). The enhancement mechanism is attributed to three synergistic effects: (1) Network Capture: The mesh structure entraps fine quartz particles, increasing the probability of bubble-particle collisions; (2) Hydrophobic Domain Construction: Grafted NaOL chains create high-density hydrophobic zones on the inherently hydrophobic graphene, enhancing bridging flocculation through hydrocarbon chain entanglement and hydrogen bonding; (3) Oriented Alignment: The graphene carrier aligns NaOL molecules, effectively extending the carbon chain length.