Extraction of rare earth metals from deep sea nodule using H2SO4 solution

Abstract Leaching of rare earth (RE) metals from the Pacific Ocean sea nodule was carried out in H 2 SO 4 medium. Preliminary study was performed to ascertain the existence of rare earth elements in the sea nodule crust. Concentration of H 2 SO 4 and temperature were found as the key factors which enhance the dissolution rate of rare earth metals. The maximum average RE leaching efficiency of 83.03% was obtained using 3 M H 2 SO 4 . At the above condition, leaching of most of the RE was ≥ 90% and the remaining metals were; Ce 44.6%, La 55.3%, Nd 84.7%, Eu 85.8%, Pr 76.4% and Th 78.8%, in which the co-extraction of other base metals like Fe, Co, Ni, Cu was high. Dilute acid i.e. 0.2 M of H 2 SO 4 and temp. 45 °C was found to be best for optimum extraction (57.6%) of total rare earth, where the co-extractions of other base metals (Cu, Co, Ni, Mn and Fe) are very less.