Avaliação de métodos de moagem de imãs provenientes de HDs de computadores e notebooks em fim de vida útil

Abstract

Hard Disks (HDs) magnets have neodymium (Nd) in their composition, a chemical element belonging to the lanthanide group and known as the Rare Earth element. The need for this element in the development of cutting-edge technology and the global dependence on Chinese supply, brings a great alert regarding the need to seek alternative sources to meet the demand for this material. With the growing increase in waste from electrical and electronic equipment (WEEE), urban mining can be applied to obtain raw material from WEEE, in order to minimize environmental impacts and recover the materials and metals present in these wastes. Recycling is one of the alternatives to meet this demand for products that use rare earths and, at the same time, reduce pollution. In this way, this study carried out the steps that precede the recycling of magnets: disassembly and mass balance of the HDs as well as their components, the segregation of components, demagnetization and evaluation of magnetism. Afterwards, the magnets were milled. Some assumptions were defined to determine the most appropriate grinding methodology, such as lower energy consumption and higher yield in the grinding process. Demagnetization was achieved in 45 minutes by heating to 350°C in a muffle furnace. In the methods determined in the present study, the most efficient grinding is performed in the eccentric mill, compared to the ball mill. The result indicates that the time of 45 minutes showed the best yield, with 20.95% efficiency in grinding, reaching a granulometry of of <0.25mm. Therefore, it was determined that grinding in the eccentric mill is the most efficient in terms of time and energy consumption, according to the method used in this work.