Recovery of a composite powder from NdFeB slurry by co-precipitation

• Optimal experimental conditions for co-precipitation were determined using simulation.
• Experimental co-precipitation of NbFeB slurry allowed the recovery of valuable metals.
• The obtained composite powders contained >99.4% valuable metals.
• The raw material guideline for preparing recycled NbFeB magnetic powders was met.
• The optimum conditions of leaching process were determined.

A co-precipitation process was used to recover composite powders from a NdFeB slurry. The most appropriate concentration of HCl and a v/w ratio were obtained in the leaching process. The optimum pH range for the co-precipitation process was determined by the log[Me(Nd, Fe, Co, Pr)]–pH curve simulated using a thermodynamics model. Fe2O3, Fe2O3·Nd2O3, and Pr2CoO4 phases were detected in the final composite powders after firing the co-precipitated products at 1273 K for 2 h. The content of the valuable metals (Nd, Pr, Co, Fe) in the obtained composite powders was greater than 99.4%, which meets the raw material requirements for preparing recycled NdFeB magnetic powders. The main advantages of the co-precipitation process are that it is efficient, low-cost, and environmentally friendly.