Study of the deposition mechanism of neodymium on an iron consumable cathode and a molybdenum unconsumable cathode in NaCl + KCl (1:1) in the temperature range 700–850° C

Abstract

With the intention of understanding processes involved in NdFe electrowinning better, the deposition processes of neodymium on inert cathodes (Mo and Ta) and consumable cathodes (Fe) have been investigated in molten NaCl + KCl (1:1) in the temperature range 700–850 °C by means of linear potential sweep voltammetry (LPSV), chronopotentiometry, X-ray diffraction and electronic microscope analysis of deposits at controlled potential. On inert cathodes the reduction of Nd 3+ was a single step process leading to Nd metal with characteristics close to reversibility. On the contrary, two steps were noticed for the deposition of neodymium on iron: a first step to form the alloy FeNd 2 and a second step where the deposition of pure neodymium was observed. The overall process had an irreversible behaviour due to the alloying properties of iron.