Nanobubble Enhances Rutile Flotation Separation in Styrene Phosphoric Acid System

Due to the weak hydrophobicity of styrene phosphoric acid (SPA), the amount used as a collector for rutile flotation is too large, resulting in high beneficiation costs. In this study, SPA was modified by nanobubbles to enhance its hydrophobicity. In this paper, the modification of SPA by nanobubbles and the adsorption mechanism of SPA on rutile surface before and after modification were studied by means of nanoparticle tracking analysis, micro-bubble flotation test, contact angle test, zeta potential test, etc. The results show that SPA can significantly increase the concentration of bulk nanobubbles, increase the flotation recovery of rutile from 55% to 69%, and reduce the dosage of SPA from 101 mg/L to 70 mg/L. Nanobubbles interact with SPA in the form of water drainage, significantly reducing the zeta potential of the rutile surface and increasing the solid–liquid interface contact angle of rutile surface. A model of the interaction between nanobubbles, SPA, and rutile surface is established, which is helpful to understand the process mechanism of nanobubble flotation.