Using phytic acid as a depressant for the selective flotation separation of smithsonite from calcite

•Phytic acid (PA) was used as depressant in the flotation of smithsonite from calcite.•The floatability of calcite was strongly reduced by PA.•The flotation of smithsonite was slightly affected in the presence of PA.•PA reacted with the Ca sites on calcite and showed stronger adsorption than that on smithsonite.•Calcite surface was covered by PA adsorption layer which inhibited the adsorption of NaOL.