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The high-pure magnetite concentrate (HPMC) was studied for a substitution of iron scale to produce the magnetic powder of strontium hexaferrite via the conventional ceramic process in this work. The magnetic powder obtained under the optimum conditions had a magneto plumbite structure, which was confirmed by X-ray diffraction (XRD). Scanning electron microscope (SEM) depicted that ferrite grains were hexagon shaped and evenly distributed with an average particle size of about 1 μm. Furthermore, a comparison of magnetic powders separately produced with HPMC and iron scale was made by detecting the magnetic properties of their sintered magnets using a permanent magnetic measuring system. The results demonstrated that the HPMC magnetic powder had a superiority over iron scale magnetic powder, and it had fully achieved the level of Y30-1 product in China. In the final part, the economic feasibility of using HPMC for magnetic powder production was verified by the cost–benefit analysis.

The high-pure magnetite concentrate (HPMC) was studied for a substitution of iron scale to produce the magnetic powder of strontium hexaferrite via the conventional ceramic process in this work. The magnetic powder obtained under the optimum conditions had a magneto plumbite structure, which was confirmed by X-ray diffraction (XRD). Scanning electron microscope (SEM) depicted that ferrite grains were hexagon shaped and evenly distributed with an average particle size of about 1 μm. Furthermore, a comparison of magnetic powders separately produced with HPMC and iron scale was made by detecting the magnetic properties of their sintered magnets using a permanent magnetic measuring system. The results demonstrated that the HPMC magnetic powder had a superiority over iron scale magnetic powder, and it had fully achieved the level of Y30-1 product in China. In the final part, the economic feasibility of using HPMC for magnetic powder production was verified by the cost–benefit analysis. [ABSTRACT FROM AUTHOR]

For the first time, ultrapure magnetite concentrate (UMC) was studied to prepare Ca-La-Co substituted magneto plumbite type (M-type) permanent ferrite magnet (PFM). UMC with a purity of 99.6 % was purified from magnetite concentrate. PFM prepared with UMC had fully reached the standard of La-Co substituted 9BF product of Pacific Metals (Br>420 mT, Hcj>374 kA/m) under the optimized chemical formula of Sr 0.3 Ca 0.3 La 0.4 Fe 11.5 Co 0.3 O 18.7 and suitable process conditions. The PFM prepared with the UMC had higher Hcb and Hcj but lower Br and BH max as Compared to the PFM prepared with the conventional high-quality iron oxide red. Impurities of SiO 2 and Al 2 O 3 in UMC thermodynamically formed Sr 2 Al 2 SiO 7 in magnetic powder, which effectively inhibited abnormal grain growth but decreased the purity of main phase. UMC owns the merits of low raw material cost, large potential production capacity and almost pollution-free. The feasibility of UMC used for the high-performance PFM preparation has been confirmed and it has a promising prospect from the views of economic gains and environmental benefits. • Ultrapure magnetite concentrate (UMC) with a purity of 99.6 % was obtained. • Permanent ferrite magnet (PFM) prepared by UMC achieved the standard of 9BF product of Hitachi. • The generation process of UMC magnetic powder could be divided into six stages. • Impurities of SiO 2 and Al 2 O 3 in UMC mainly formed Sr 2 Al 2 SiO 7 in PFM. • The economic benefit analysis of PFM prepared by UMC was studied. [ABSTRACT FROM AUTHOR]

The hexagonal BaNd x Fe12− x O19( x=0.1−1.0) fine powders with M-type structure were synthesized by sol-gel auto-combustion high-temperature synthesis method. The structure of powders, gels’ combustion and magnetic properties of powders were respectively studied by means of X-ray diffractometer (XRD), differential thermal analysis-thermogravimetric analysis (DTA-TG) and vibrating sample magnetometer (VSM). The powders before and after combustion and calcination at 450–850 °C with different mole ratio of Nd to Ba (0.1–1.0) were compared in terms of XRD. In addition, the effects of different synthesis conditions on magnetic properties of powders were also discussed. The results show that at pH 7.0 or so, mole ratio of citrate to nitrate (1–3) and calcination temperature of 850 °C for 1 h, M-type BaNd x Fe12− x O19( x=0.1−1.0) fine powders can be obtained, and the coercive force reaches 436880 A·m−1 at x=1, which is far greater than that of barium permanent ferrite (BaFe12O19). [ABSTRACT FROM AUTHOR]