The mass transfer and mechanism of H3PO4 from low concentration HCl-route wet-process phosphoric acid by the mixture of n-butanol and isopropyl ether

•The mixed solvent of nBA and IPE was first used to extract H3PO4 from HCl-route WPA.•The relation of Ei, tal and N for all tested components were summarized.•The thermodynamic data of extraction process was calculated.•The mechanism and stage of H3PO4 extraction were analyzed.