Preparation Of Mn-zn Ferrite, With The Recovery Of Rare Earth Ndfeb Waste Residue

In this paper, the waste of NdFeB scraps after recovering Rare Earth was used to produce Mn-Zn ferrites. Use iron scraps and the waste of NdFeB scraps after recovering Rare Earth as the raw materials .After leaching, purify, co-precipitation, calcine and sintering, we can get Mn-Zn ferries. The composition and the characterization of product were detected by thermal analysis (TG-DTA), X-ray Diffraction (XRD), Scanning Electronic Microscope (SEM) and Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). From the date of experiment, we have:Under the temperature of 80℃, add 40wt% H₂SO₄, one and a half of theories quantity, after 1h, the leaching rate of Fe is more than 96%. The conversion rate of Fe³⁺ to Fe²⁺ is more than 99.7%. The concentration of Cu²⁺ is less than 5mg/L.Purify the leaching liquid (content cobalt) by CaCO₃, (NH₄)₂S, and NH₄F. The purity FeSO₄ liquid was obtained. The rejection of Al³⁺, Co²⁺, Ca²⁺ and Mg²⁺ is 96.47 %,80.83%,95.72% and 95.62% separately . The rejection of RE³⁺ is nearly 100%.After crystallization and filtration, we can get spent liquid and FeSO₄ crystallize from the leaching liquid of non-cobalt waste. The spent liquid is recycling to leaching. FeSO₄ crystallize is purify by recrystallization. After recycling 5 times, in the spent liquid, the concentration of Al³⁺ is more than 3.46g/L, and RE³⁺ concentration is 9.53g/L. After remove Al³⁺, the spent liquid is extracting by P507. For 5 times a liquid that RE³⁺ concentration is 36.81g/L is obtained. By 3 times recrystallization, FeSO₄ crystallizes get a high purity.According to the formulation, add MnSO₄, ZnSO₄ and FeSO₄ in to de-ionized water. Co-precipitation it by NH₄CO₃, after filtration, washing, drying and grinding, precursor was obtained. The precursor was calcined at 800℃for 2 h, Mn-Zn ferrites powder was obtained. The powder have more than 40% spinel phase. The size of the powder is 0.4um, even, Spheroid. After granulation, molding, sintering at 1300℃for 5 h, we can get the Mn-Zn ferrites with big grain size, and have a little pores.