Novel eco-friendly low cost and energy efficient synthesis of (Nd–Pr–Dy)2Fe14B magnetic powder from monazite concentrate

Abstract

Syntheses of Nd2Fe14B magnetic powder by conventional method is a complicated multi-step process, which produces harmful pollutants and consumes a huge amount of energy and resources. Herein we report a simple chemical route for the preparation of (Nd–Pr)2Fe14B magnetic powder using monazite concentrate as a precursor. Th, U, Sm, and La impurities were removed from monazite leachate by roasting, solvent extraction and leaching the concentrate. Purified leachate consisting of Nd and Pr Chlorides was added to the FeCl3 solution, and the solution produced was co-precipitated with NaOH. RE and Fe hydroxide precipitates were converted to the oxides by annealing at 700 °C. Boric acid and CaH2 were added in the RE and Fe oxides produced, and this mixture was reduced and diffused to (Nd–Pr)2Fe14B. Magnetic properties of the (Nd–Pr)2Fe14B produced were enhanced by introducing antiferromagnetic coupling, induced by Dy addition and efficient removal of CaO byproduct through ball milling in ethanol which increased the BHmax from 3.9 to 11.45 MGOe. Process reported is energy efficient, environment-friendly, time saving and low-cost.

Purification and Characterization of Monazite from Bangka using Mechanical-Magnetic Separation Method

“…Over the past ten years, there has been a huge increase in interest in the beneficiation of rare earth elements (REE) minerals. The demand for REEs has surged due to the various industrial and technological applications of REEs, including microwave communications, electric vehicles, wind turbines, lasers, navigation and control, and rechargeable batteries (Abaka-Wood et al, 2024;Chung et al, 2020;Haider et al, 2021;Omodara et al, 2019).…”

Demagnetization properties study on NdFeB permanent magnets under impact load

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