Investigation of the effect of phosphoric acid as an acidic medium in flotation separation of dolomite from magnesite

•Dolomite can be separated from magnesite by flotation with oleate at pH 5 or less.•Mineral separation is further enhanced using phosphoric acid for pH control.•More oleate adsorbs on dolomite than magnesite at acidic pH by chemical interaction.•Higher Ca dissolution from dolomite contributes to higher dolomite flotation.•Surface PO4 species may decrease magnesite dissolution and prevent oleate adsorption.