Effect of Iron(III) ions on rutile flotation: Surface properties and adsorption mechanism
Xinyu Zhang, Liuyi Ren, Shenxu Bao, Yimin Zhang
Abstract
Various studies have shown that the presence of metal ions in the slurry can significantly impact flotation . However, it was still uncertain how iron, a typical metal ion, affected rutile flotation. Micro-flotation experiments, x-ray photoelectron spectroscopy , icp-oes, solution chemistry calculation, zeta potential and contact angle test were used to explore the effect of iron ions on the surface properties and floatability of rutile in this investigation. Micro-flotation results showed that iron ions not only substantially increased the rutile flotation recovery from 42.27 % to 75.69 % at pH = 4, but also converted the optimal pH of flotation from a point (pH = 4) to a platform (pH = 4–8). Solution chemistry calculations indicated that iron ions could form complexes with hydroxyl to produce FeOH 2+ , which reacted with benzohydroxamic acid (BHA) to create [Fe(C 7 H 6 NO 2 ) 2 ] + at pH=4–7. The analysis conducted through X-ray photoelectron spectroscopy , coupled with the results obtained from contact angle measurements, revealed that the complex [Fe(C 7 H 6 NO 2 ) 2 ] + had the capability to engage with Ti-OH groups, improving the hydrophobicity of rutile surface. Zeta potential analysis results further illustrated that Fe 3+ /BHA complexes reinforce the adsorption of BHA and iron ions onto rutile surface by the formation of [Fe(C 7 H 6 NO 2 ) 2 ] + . In addition, the O1s peak fitting results and ICP-OES analysis results proved that at the same pH, 60 mg/L was the optimal concentration for iron ion activation, which may be limited by Saturated adsorption capacity of [Fe(C 7 H 6 NO 2 ) 2 ] + .