Enhanced Flotation Separation of Iron and Silicon with Branched Block Polyethylene Oxide Polypropylene Oxide and Sodium Oleate: Mechanisms and Flotation Behavior

This study explores the strengthening mechanism of the surfactant branched block polyethylene oxide–polypropylene oxide (BB-PEO-PPO) in sodium oleate (NaOL) flotation systems. A comprehensive characterization of BB-PEO-PPO was performed using flotation experiments, contact angle measurements, surface tension analysis, zeta potential measurements, infrared spectroscopy, and foam dynamics assessments. Flotation results showed that the combination of BB-PEO-PPO and NaOL improved iron recovery by 2.71% and reduced the total iron (TFe) grade in tailings by 2.05%, demonstrating a significant enhancement in collecting efficiency. The addition of BB-PEO-PPO effectively reduced foam size and lowered the zeta potential on the surface of activated quartz. At a slurry temperature of 15 °C, BB-PEO-PPO increased the solubility of NaOL radicals, facilitating their chemical adsorption onto activated quartz and improving the hydrophobicity of quartz particles. Notably, the presence of BB-PEO-PPO extended the flotation foam discharge time (D50) by 50% without substantially increasing foam volume, thereby significantly enhancing foam stability.