Abstract: The efficient recovery of fine-grained weakly magnetic iron ores remains a critical challenge in mineral processing,
particularly for hematite with low magnetic susceptibility. The present research focuses on the low capture efficiency of
-20 μm hematite in high gradient magnetic separation,and investigates the regulation of sodium silicate,crosslinked corn
starch(CLCS) and pulp pH on the separation efficiency by constructing a synergistic method of "dispersion-selective bridging
agglomeration-high gradient magnetic capture" for artificial mixed ores,and then investigates the regulation of sodium silicate,
crosslinked corn starch and pulp pH on the efficiency of the separation. The interfacial chemistry-agglomeration morphologymagnetic
response relationships were analyzed via laser particle size analysis (LPSA),Zeta potential measurement,UV-Vis
spectroscopy,mineralogical microscopy,and scanning electron microscopy (SEM). The experimental findings demonstrated that
the iron grade and beneficiation efficiency exhibited an enhancement of 3. 84 and 16. 69 percentage points,respectively,under
the optimal conditions of crosslinked corn starch dosage of 15 mg/ L,sodium silicate dosage of 15 mg/ L,and pH=9. The mechanism
analysis revealed that the optimal dosage of sodium silicate enhances the dispersion of hematite and quartz. However,
when the sodium silicate dosage exceeds the optimal level,it leads to a reduction in the adsorption sites on the hematite surface,
thereby weakening the agglomeration effect. CLCS on hematite is primarily attributable to the electrostatic adsorption effect
on the surface of the static adsorption effect. However,excessive crosslinked corn starch can induce a spatial site-disturbing
effect,which in turn leads to the formation of a loose porous structure and dispersion phase repulsion in the agglomerates. This
non-selective agglomeration behavior leads to the weakening of the interface separation characteristics between hematite and
quartz,which eventually leads to the attenuation of the separation efficiency of high gradient magnetic separation. This study provides theoretical and technical support for the "dispersion-selective bridging agglomeration-high gradient magnetic capture"
technology.