To address the beneficiation technical challenges in the Guizhou region, where rhodochrosite and quartz are difficult to separate and the recovery rate of fine-grained manganese resources is low, this study conducted experiments using a combined process of sodium oleate hydrophobic flocculation coupled with high-gradient magnetic separation, and systematically elucidated its interfacial action mechanism. The experimental results show that sodium oleate can selectively adsorb on the surface of rhodochrosite particles, forming a dense hydrophobic film, while only weakly adsorbing on the quartz surface, significantly enhancing the differences in surface physicochemical properties between the two minerals. Under the optimal conditions of pH 10, sodium oleate concentration of 4×10^-5 mol/L, and stirring speed of 600 rpm, selective hydrophobic flocculation of the minerals can be achieved, effectively increasing the particle size of the target mineral, solving the issues of fine manganese loss with quartz and quartz contamination in manganese concentrate. After treatment with high-gradient magnetic separation, the final manganese concentrate grade reached 18.79%, with a manganese recovery rate of 85.84%, an improvement of 8.88 percentage points compared with traditional magnetic separation processes. Combined analyses of zeta potential, contact angle testing, EDLVO theoretical calculations, as well as extended BPMA, FTIR, and XPS characterization confirmed that sodium oleate regulates the surface charge and hydrophobicity of mineral particles through chemical adsorption, effectively promoting the aggregation of manganese-containing mineral particles while maintaining the dispersion state of quartz particles. This study provides important theoretical basis and technical support for the efficient separation and recovery of fine-grained manganese minerals.