The mechanism of selective dispersion between micro-fine titanaugite and ilmenite particles caused by acid surface pretreatment in pulp

In this work, acid surface pretreatment improved the selective dispersion between micro-fine titanaugite (−19 μm) and ilmenite particles in pulp. Microflotation experiments showed that as the mass percentage of micro-fine titanaugite in mixed ore increased, the separation index in ilmenite flotation decreased due to micro-fine titanaugite adsorbed on ilmenite surfaces, while acid surface pretreatment weakened this adverse effect. Turbidity, optical microscope, SEM-EDS, and EDLVO theory analyses suggested that after acid surface pretreatment, these aggregations between ilmenite particles and between titanaugite particles reinforced, and they were related to the decreased surface hydrophilicity of ilmenite and the formative calcium precipitate on titanaugite surfaces, respectively. Meanwhile, the difference in surface hydrophilicity of out-of-phase particles increased. These variations between particles led to a reduction in aggregation between out-of-phase particles. AFM adhesive force analysis proved that after acid surface pretreatment, the adhesion between micro-fine titanaugite and ilmenite particles decreased, and it was lower than the increased adhesion between in-phase particles. A greater improvement in selective dispersion between out-of-phase particles treated with acid surface pretreatment occurred in pulp, further enhancing the flotation index of ilmenite.