An iron density stimuli-responsive depressant for selective depression of chlorite in the flotation separation of both iron-containing mineral

• Developed an iron density stimuli - responsive depressant for separating refractory specularite & chlorite. • Designed an eco-friendly ionic liquid depressant using surface iron atomic density differences of specularite and chlorite. • The stimuli-responsive ionic liquid switches polarity via temperature, pH, enabling selective chlorite depression. • Solves the issue of conventional depressants' non - selective inhibition of target & gangue minerals. This research focuses on enhancing the flotation separation of specularite and chlorite. A novel Fe ion surface density-stimuli responsive ionic liquid inhibitor, taurine-choline liquid (TZL), was employed, with DDA as the collector and TZL as the depressant. The adsorption mechanism of TZL was comprehensively explored. Single-mineral-flotation results show that at pH 7, TZL effectively increases the floatability difference between specularite and chlorite, achieving a specularite recovery of 4.34 % and a chlorite recovery of 90.12 %. Artificial mixed-mineral flotation experiments further confirm TZL’s potential as a depressant for their separation. TZL preferentially adsorbs on the specularite surface, reducing its contact angle from 50.3° to 21.8°, while also adsorbing on the chlorite surface, increasing its contact angle from 42.1° to 51.9°. FT-IR and XPS analyses provide evidence that TZL adsorbs on the surfaces of these minerals mainly through the interaction of hydroxyl or amino groups with Fe ions. TZL is mainly adsorbed on the Fe sites on the mineral surface through hydroxyl or amino groups. When the density of Fe on the mineral surface is relatively high, the hydrogen bonds in the middle of TZL are broken, making the mineral more hydrophilic. When the Fe density is low, the structure of TZL remains unchanged, and the mineral exhibits greater hydrophobicity. Finally, the conceivable interaction mechanism of TZL in specularite/chlorite separation is derived, which may offer new insights for the design of mineral-related reagents.