Recovery of Nd from Nd-Fe-B magnet scrap of computer Hard Disk Drive

Abstract

Neodymium is a rare earth element and very much in demand due to its Nd-Fe-B permanent magnet. But, now conventional route to recover the metal from minerals is not able to accomplish the required demand. Due to very wide field applicability of permanent rare earth magnets, and not proper methods available to recycle & reuse the same, there is a stock pile of magnet scrap around the globe. So, research for recycling the scrap is attracting every one in order to minimize the demand-supply gap and less dependent on the others for import. Present report is a hydrometallurgical route for the recovery of Neodymium from Nd-Fe-B magnet scrap from Hard Disk Drive (HDD) of obsolete computers through acid leaching followed by precipitation. Almost 96% of Nd present in the scrap was recovered with 2M H2SO4 at room temperature at S/L ratio 1:10 (100 g/L) in 90 minutes. The pH of the leach liquor obtained was increased using NaOH solution and was maintained between the ranges from 0.5 to 2. The pH value > 2 would result in the precipitation of Fe along with Nd. Thus, to avoid the impurity formation due to Fe precipitation, the pH value should < 2. The Nd precipitate formed was treated with HF solution when NdF3 was formed.