**2.1 Protecting the environment with recycling rare earth elements**

One way to reduce the environmental impact of permanent magnets is to recycle rare earth elements from old or discarded magnets. This process involves extracting and purifying the rare earth elements from the magnet, which can then be used to create new magnets. Electronic waste, also known as e-waste, may contain rare earth elements [7]. These elements are used in the production of electronic devices such as smartphones, laptops, and televisions. When these devices are disposed of improperly, the rare earth elements they contain can end up in landfills or incinerators. This not only wastes valuable resources but also poses a risk to the environment and human health. Recycling e-waste is one way to recover rare earth elements and reduce the environmental impact of their disposal. However, the process of extracting these elements from e-waste can be challenging and expensive due to their low concentration and complex composition. Therefore, it is important to design electronic devices with recycling in mind and develop more efficient methods for recovering rare earth elements from e-waste [8]. There are several methods of rare earth element (REE) recycling, including:


*Perspective Chapter: Environmental Impact of Modern Permanent Magnets DOI: http://dx.doi.org/10.5772/intechopen.111661*


#### **Table 1.**

*Compares some properties of permanent magnetic materials.*

6.Biometallurgy: This method involves using microorganisms to extract and recover REEs from waste materials such as electronic waste or mine tailings [14].

In general, these methods can help reduce our dependence on mining for new sources of rare earth elements and promote sustainable practices in the industry. Recycled rare earth elements can be used in a variety of applications, including:


The elements used to make magnets are not always iron. Instead, magnets are usually made of alloys, including some rare metals. The most common of these rare metals is

#### *Modern Permanent Magnets – Fundamentals and Applications*


#### **Table 2.**

*List of rare earth elements used to make magnets arranged in order of importance.*

neodymium. Neodymium magnets are the strongest of the rare earth magnets. Other rare metals used in magnet production include dysprosium and samarium. Cobalt is another metal used in the production of magnets, as shown in **Table 2** [22, 23].

Different methods are used to manufacture rare earth magnets, but one of the most common ones is called powder metallurgy. This method involves the following steps, as shown in **Figure 1**.

The raw materials used in the manufacture of rare earth magnets are neodymium, iron, and boron. These materials are firstly crushed into small particles and then mixed together in a certain proportion. The mixed raw materials are then melted in a vacuum furnace at high temperatures to form a molten alloy. The molten alloy is then cast into a mold to form a solid block of material. The solid mass of the material is then ground into a fine powder using a ball mill. Followed by compacting the fine powder into the desired shape using a hydraulic press. Next comes the sintering process, where the pressed powder is heated in a vacuum or in an inert atmosphere to a high temperature (about 1000°C), allowing some of the elements to melt and bond together. This process is called liquid phase sintering and gives the magnet its final strength and density. The sintered magnet is then ground, sliced, or cut into its final shape. This can be done with diamond tools or wire saws. Finally, the magnet is coated with a protective layer to prevent corrosion and improve its performance. This method allows for precise control over the composition and microstructure of the magnet, resulting in magnets with high magnetic properties and excellent performance characteristics [24].

**Figure 1.**

*The method used in the manufacture of rare earth magnets.*

*Perspective Chapter: Environmental Impact of Modern Permanent Magnets DOI: http://dx.doi.org/10.5772/intechopen.111661*

### *2.1.2 Challenges in recycling rare earth elements*

There are many challenges associated with recycling rare earth elements. One major hurdle is that the amount of REE used in final products ranges from less than a milligram to several kilograms [25]. This means that assembly and disassembly of REE-containing devices can be difficult. In addition, earth-recycling methods require rare conventional hazardous chemicals such as hydrochloric acid, a lot of heat, and, therefore, a lot of energy [26].

### **2.2 Protecting the environment with biodegradable magnets**

While magnetic materials have many beneficial applications, they also come with environmental concerns. Traditional magnetic materials, such as neodymium and samarium-cobalt, are not biodegradable and can have negative long-term effects on the environment if not disposed of properly. Biodegradable magnets have emerged as a promising alternative that can mitigate these environmental concerns [27, 28]. These materials are typically made from biodegradable polymers, such as polylactic acid or cellulose, mixed with magnetic particles such as iron oxide or ferrite. The advantages of biodegradable magnets include their ability to degrade naturally over time, reducing the amount of waste that ends up in landfills or oceans [29]. They also have lower toxicity levels and can be produced using more sustainable manufacturing processes, making them a more environmentally friendly option. In General, the use of biodegradable magnets has the potential to improve the sustainability of various industries that rely on magnetic materials, such as electronics, automotive, and medical industries.
