The Influence of Mg2+on Flotation Separation of Quartz from Talc: Process Optimization and Mechanism Exploration

This study proposes a regulation strategy to address the intractable flotation separation challenge of quartz-talc associated systems. Herein, we identify a cation-gated flotation-selectivity mechanism in aqueous media: site-specific Mg 2+ adsorption at mineral interfaces dictates separation. At pH 2.0 and 150   g/t collector, the concentrate assayed 99.97% SiO 2 with 93.97% recovery. Adsorption simulations validate that the selective adsorption of Mg 2+ on the hydroxylated quartz surface adheres to the standard interfacial activation mechanism. It augments the contact between the quartz surface and water molecules, causes structured reorientation of water molecules, facilitates quartz surface hydroxylation, and increases system hydrophilicity. Mg 2+ titration elicits a biphasic switch: below 3×10 -3   mol/L it site-selectively hydroxylates quartz, amplifying hydrophilicity; above this threshold it collapses the electrical double layer, indiscriminately hydrophilizing all surfaces and abolishing selectivity. These findings provide a theoretical basis and a technical strategy for the efficient purification of complex associated quartz ores.