Recovery of rare earths and niobium from a potash feldspar ore beneficiation tailings

In this paper, a hydrometallurgy process was investigated for recovering rare earths (REs) and niobium (Nb) from a potash feldspar ore beneficiation tailings. Firstly, the REs and Nb could be leached from potash feldspar ore beneficiation tailings by sulfuric acid roasting-water leaching process, and the effects of the roasting temperature, roasting time, sulfuric acid addition, leaching temperature, ratio of solid to liquid and leaching time for REs and Nb leaching rate were investigated, and the REs and Nb leaching rate could reach to 89.9% and 80.6% respectively at the optimum test conditions. Then, the REs was removed from the leaching liquor by adding HF, the precipitation rate could reach to 91.53%. The rare earths fluoride (REF3) with the purity 60.51% was obtained, and the REs recovery rate reached to 70.6%. Finally, the Nb was recovered by solvent extraction with methyl isobutyl ketone (MIBK), Nb extraction rate could be reached 99.59%. The loaded organic phase could be stripped easily, nearly all niobium was stripped using 0.5 M sulfuric acid as strip liquor. The Nb2O5 products with the Nb2O5 content 87.61% was obtained by ammonia precipitation-roasting process, and the recovery Nb was 76.31% in the whole process.