Green flotation of ilmenite with bio-based sophorolipid: New insights into the effects of temperature on interfacial adsorption

Temperature is an important factor influencing minerals flotation, particularly when temperature variation over the year is severe. This study investigated the impacts of temperature on adsorption behaviour of sodium oleate (NaOL) and sophorolipid (SL) on ilmenite surface and the resultant ilmenite floatability. XPS and TOF-SIMS results indicated that higher temperatures could strengthen NaOL and SL adsorption on ilmenite surface, thereby improving ilmenite floatability. It was further demonstrated that SL, with a much lower critical micelle concentration (CMC) than NaOL, provided better ilmenite surface coverage and induced significant Raman spectral changes. All these findings were supported by flotation results that SL could achieve higher ilmenite recoveries than NaOL under the same conditions. Particularly when the temperature was low, SL still exhibited superior performance in floating ilmenite than NaOL. Therefore, as the eco-friendly and bio-based surfactant, SL was a promising alternative in ilmenite flotation to make its processing more sustainable.