Recovery of rare earth elements from deep-sea mud using acid leaching followed by selective solvent extraction with N1923 and TBP

•The recovery of REEs from a novel resource of deep-sea mud is focused.•A efficiently technological route, including acid leaching, solvent extraction and precipitation, was proposed.•The detailed characterization and process investigation were conducted.•80.20% REEs were recovered as a pure REEs oxide with a content of 81.82%, while Al, Fe, Mg, Ca, Mn and P were less than 0.15%.