Development of a novel eco-friendly depressant for the selective flotation of magnesite from dolomite: Investigation of Luteolin’s effectiveness and mechanism of action

Magnesite and dolomite exhibit similar crystal structures, chemical compositions, and surface properties, which pose significant challenges to their flotation separation. In response to the growing need for efficient and environmentally sustainable decalcification of magnesite, this study introduces luteolin (LUT), a novel eco-friendly depressant. The selective depression efficiency of LUT on dolomite within the magnesite flotation system was systematically assessed. Optimal flotation conditions (pH 11.0, LUT concentration of 60 mg/L, and NaOl concentration of 120 mg/L) resulted in a concentrate with 43.05 % MgO and 4.98 % CaO, effectively achieving the separation of magnesite from dolomite. The depression mechanism of LUT was thoroughly investigated through a combination of zeta potential, contact angle, FTIR, XPS, and AFM analyses. The results indicate that LUT’s hydroxyl groups preferentially adsorb onto the calcium sites of dolomite, preventing subsequent adsorption of sodium oleate, while exhibiting minimal interaction with magnesium sites on magnesite, thus preserving its flotation behavior. This study offers a promising, environmentally friendly solution for the selective separation of magnesite from dolomite.