Recycling of Strontium Ferrite Waste in a Permanent Magnet Manufacturing Plant

Abstract

Residues resulting from the manufacture of strontium ferrite magnets have been recycled for further use in magnet fabrication instead of disposal as waste. The quality of the recycled ferrite powder has been tested and compared to that of the new starting ferrite material. The magnetic properties of the recycled powder not only match those of the starting material acquired by the company for the production of magnets but exceed them. A coercivity value 3.5 times larger than that of the new starting ferrite powder, accompanied by a 25% increase in remanence, makes this material a new and improved ferrite product to re-enter the production chain in the factory with an extended applications range. This improvement is proven to be due to tuning of the morphology and microstructure through processing and subsequent heat treatment. The use of processing conditions in the same range as those typically used in the preparation of ferrite powders and magnets, in combination with the superior magnetic quality of the resulting powders, makes this method a suitable path to guarantee sustainability and an efficient use of resources in permanent magnet companies.

Controlled Preparation of Different Proportions of Metal Fe-Mn from Waste Mn Ferrite by Molten Salt Electrolysis

“…The theoretical decomposition voltages of MnCl2 and FeCl3 at 800 °C are 1.8 V and 0.8 V, respectively. The decomposition voltages of FeCl3 and MnCl2 are calculated by Equations (2) and (4). Thus, the decomposition voltages of MnCl2 and FeCl3 at 800 °C are 2.3 V and 1.1 V, respectively.…”

“…Ferrites are widely used in the electronics industry [1,2]. Since 2008, more than 250,000 tons of Mn-Zn ferrite have been produced annually in China [3].…”

Recycled strontium hexaferrite powder behavior in the magneto fluidized state in dependence of the chamber fill factor

“…Strontium hexaferrite powders are widely used in the powder metallurgy as materials for electric motor stators due to their magnetic stats and thermal resistance [1][2][3][4][5]. The recycled old magnets and the waste of the magnet manufacturing can be reused [6][7][8]. This decreases the pollution and increase the level of sustainability of the production.…”

Advances in 3D printing of magnetic materials: Fabrication, properties, and their applications

“…Magnetic materials are typically referred to objects that could produce their own magnetic field, and the overall magnetic behaviors are particularly depending on the orbit and spin motions of electrons. From the aspect of behavior under magnetic field, magnetic materials can be divided into several categories, such as ferromagnets, time, residues are generated during most manufacturing processes, and the volume of residues rapidly scales up as a result of the large market of magnetic materials [13].…”