**1. Introduction**

In the past, a large number of physical and chemical processes have been widely used to manufacturing the different types of electronic devices with the desired characteristics [1, 2]. Beyond the supply of raw materials during manufacturing cycles, however, the environmental and human

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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health impacts have restricted the wide-scale production [3, 4]. In response to those concerns, coherent procedures that enable device manufacturers to reduce or eliminate toxic substances in their designs will be a major advance toward green development.

ferrites an excellent material for these filters operating over the 50–450 kHz frequency range. For five decades ferrite components have been employed in a widening range of applications [10]. Currently these are useful as magnetic devices into applications such as switching mode power supplies (SMPS) and lighting electronic ballasts, matching and storage devices, interfer-

Mn-Zn Ferrite as Recycled Material Resource Based on Iron Oxide Suitable to Functional Green…

http://dx.doi.org/10.5772/intechopen.72418

It is well known that the magnetic structure of a Mn-Zn ferrite is noncollinear in a certain range of temperatures and magnetic fields, which results from competitions between antiferromagnetic interactions of their sublattices, aligning the sublattice magnetizations antiparallel to each other, and under an external field will try to align them parallel to each other [11]. Such magnetic interactions between d ions had allow to predict magnetic properties and thus to calculate composition with structure parameters; however, dominant interaction is exchange coupling between Mn and Fe ions caused by the magneto-crystalline anisotropy. Furthermore, it has been shown that the states of Mn and Fe ions support both ferromagnetic and antiferromagnetic long-range orders [12]. At lower field conditions, bulk ferrites always are accompanied by characteristic anomalies in their physical properties, like domain structure [13]. The last indicates that the resistivity in their grain boundaries will be short-circuited due to the domain wall excitation by the applied alternating magnetic field when the fre-

Mn-Zn ferrites have been manufactured by a complex composition of iron oxide (*Fe*<sup>2</sup> *<sup>O</sup>*<sup>3</sup>

with manganese oxide (MnO) and zinc oxide (ZnO) by using ceramic process technologies. Ceramic process can be divided into four functions: preparation of the powder, forming powder into cores, sintering cycle, and finishing stage [9, 10]. Thus, taking into account environmental impacts, the use of energy resources, etc., efficiency in the processing technology of bulk ferrites must be studied into LCA methodology, including product manufacturing, use phase, and end of life. **Figure 1** illustrates the schematic of the life-cycle assessment methodol-

LCA methodology with the stages coverage in **Figure 1** is understood in accordance with

oxides as constitutes are weighed and thoroughly mixed into a homogeneous mixture to form slurry and then mixed in a ball mill [9, 15]. After calcining process in air atmosphere at the powder temperature of approximately 1000° C, partial decomposition of the carbonates and

Besides, forming powder into core geometries is done by dry pressing process, and to achieve final magnetic and mechanical characteristics in bulk ferrites, sintering cycle must be completed. This phase consists in gradual ramping up from room temperature to approximately

C into air atmosphere. After, the temperature is further increased to the final temperature

most ferrites will require some shape of finishing in accordance with their magnetic performance. Subsequently, the Mn-Zn bulk ferrites are in general employed as SMPS into product manufacture (see **Figure 1**). However, severe problems as the combination of core losses (hysteresis, eddy currents, and residual), winding losses, and failures in power semiconductor

C, after a cool-down cycle is needed at reduced oxygen pressure. Finally,

the following. During the preparation of the powder, raw material (*Fe*<sup>2</sup> *<sup>O</sup>*<sup>3</sup>

) mixed

191

) and MnO and ZnO

ence suppression, etc.

ogy for bulk ferrites.

cycle from 1000 to 1500°

800°

quency changes from 10 kHz to 1 MHz [14].

oxide evaporation of impurities occurs.

It is well known that for the materials selection for conventional electronic devices, the primary purpose is link material and function. The latter has been achieved by focusing on selected material attributes, including mechanical, thermal, electrical, optical, and chemical properties, and processing characteristics [5]. Also, traditionally selection has been focused solely on cost; nevertheless, availability, environmental consequences of use, and recycling must also become important factors. Recycling is the transformation of waste into usable products or materials; it is sometimes referred as resources recovery which might be often more environmentally gentle than using raw materials owing to reduced energy use and elimination of hazardous gases and other pollutants [6].

The assessment of recycling potential must be based on established principles, including knowledge of the relative ease of "liberation" of the materials of interest and specific characteristics during physical separation technology and shredding in accordance with the international materials life-cycle initiative established by the United Nations Environmental Program (UNEP) and the Society for Environmental Toxicology and Chemistry (SETAC) [7]. Conversely, design of products profoundly will affect the potential recyclability of the resources they contain [8].

The chapter is focused on recovery of one useful material based on iron oxide well known as Mn-Zn ferrite extracted from unusable electronic systems. Using a scientific tool known as life-cycle assessment (LCA), which takes into account all stages of the life cycle of products or materials, including processing technology, manufacturing processes, use phase, and end-of-life routes, will deliver powerful basis to quantifying the recycling performance. Thus, researching Mn-Zn ferrites in foil shape will provide theoretical basis for open-loop recycling, converting waste materials into suitable materials in its second life.

This chapter is organized as follows. After introducing the recycling concept and their environmental advantages, it presents the Mn-Zn foil ferrites as recycled material resource explaining the source of their uncommon physical properties. Then the following sections are focused on analysis of both structure and conduction properties to functional green devices into engineering applications.
