Study on inhibition effect and mechanism of sodium humate in hematite reverse flotation

•NaHA selectively inhibited hematite and realized the effective separation of quartz and hematite.•NaHA obviously changed the zeta potential of hematite and prevented the further adsorption of DDA.•The adsorption capacity of NaHA on hematite surface was much greater than that on quartz surface.•There was chemical adsorption of NaHA on the surface of hematite but no on the quartz.•NaHA adsorbed on the surface of hematite through coordination with surface iron.