Effective reverse flotation separation of siderite from hornblende using pentaethoxylated tallow amine as a selective collector

•PTA exhibited selective collection performance for hornblende.•Hydrogen bonding and electrostatic attraction enhanced PTA adsorption on hornblende.•The strong adsorption of PTA significantly improved hydrophobicity of hornblende.•The attractive interactions strengthened the adhesion of hornblende to air bubbles.•Efficient flotation separation of siderite from hornblende was achieved by PTA.