Neodymium recovery by precipitation from synthetic leach liquor of concentrated rare earth mineral

Abstract

The demand of high purity metals and continuous depletion of high grade ores has made an important global issue for the selective recovery of metal values from minerals/ waste resources. To extract Nd from mineral or waste resources, initial studies were made using synthetic leach liquor of Nd containing 27.77 g/L Nd and 8.36 g/L Fe(pH 0.33). The solution was prepared by dissolving metal alloy of composition 30.10% Nd, 68.00% Fe, 1.07% Ni and 0.83% B in sulfuric acid. A double salt complex of Nd was precipitated from this synthetic solution using 50% NaOH. The 95.89% of Nd was precipitated out at pH 1.83. Further increase in pH of solution, showed the precipitation of Fe along with Nd. Leaching of this double salt using 20% HF (v/v) solution, resulted in the formation of pure neodymium fluoride (NdF3) salt. These optimum parameters will be helpful to the scale up studies for the selective selective extraction of Nd from the actual leach liquor of minerals or solution containing Nd.