Reverse flotation of hematite using a novel bio-collector derived from vitamin E

Reverse anionic flotation of hematite-silica mixtures was evaluated using micro-flotation tests with vitamin E sodium succinate (VE_SS), a novel bio-based collector. A binary feed containing 30 wt% hematite and 70 wt% silica was prepared from separately sourced mineral samples, hematite from a commercial mine and silica from Holcim, with purities of approximately 93.6 wt% Fe 2 O 3 and 97.8 wt% SiO 2 , respectively. Flotation tests and surface characterisation were used to identify suitable operating conditions and interpret the observed separation behaviour. Micro-flotation was conducted at pH 11.5 using soluble starch as hematite depressant and CaCl 2 as quartz activator. The optimum VE_SS dosage was 250 ppm, at which hematite recovery to the concentrate remained above 95% (97.5–97.7%), silica recovery to the concentrate was reduced to about 7.7%, corresponding to about 92% silica rejection, and the concentrate total iron grade reached 55.3 wt%. The corresponding separation efficiency and selectivity index were approximately 90% and 21.9, respectively. Complementary zeta potential, contact angle, and FTIR measurements showed that VE_SS adsorption was promoted on Ca 2+ -activated quartz under alkaline conditions, while starch maintained hematite as hydrophilic under the selected flotation conditions. These results demonstrate the feasibility of VE_SS as a bio-based collector for reverse anionic flotation of hematite in a controlled binary system.