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Recycling of Li-Ion Batteries (LIBs) is still a topic of scientific interest. Commonly, spent LIBs are pretreated by mechanical and/or thermal processing. Valuable elements are then recycled via pyrometallurgy and/or hydrometallurgy. Among the thermal treatments, pyrolysis is the most commonly used pre-treatment process. This work compares the treatment of typical cathode nickel-cobalt-aluminum (NCA) material by conventional pyrolysis, and by a microwave assisted pyrolysis. In the conventional route, the heating is provided indirectly, while via microwave the heating is absorbed by the microwaves, according to the materials properties. The comparison is done with help of a detailed characterization of solid as well as the gaseous products during and after the thermal treatment. The results indicated at least three common stages in the degradation: Dehydration and evaporation of electrolyte solvents (EC) and two degradation periods of EC driven by combustion and reforming reactions. In addition, microwave assisted pyrolysis promotes catalytic steam and dry reforming reactions, leading to the strong formation of H2 and CO.

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In the past years the topic of WEEE recycling has gained more relevance due to increased production and reduced effectiveness in metal recovery. Therefore, new processing technologies are evolving today as result of the increasing heterogeneity of WEEE. Such is the case of pyrolysis as an upgrading and conditioning method for different types of complex scraps, which also facilitate further mechanical separation of metal as well as production of an alternative fuel source. In this work, it has been concluded that pyrolysis can be easily integrated as a preprocessing step in a resource efficient recycling route. PrefaceThe electronic industry provides devices which in the recent years have become essential in modern life. However, strong competition encourages the industry to produce improved performance of devices, increase number of features and reduced production costs in each generation of products, which bring the balance between production, waste generation and recycling processes to its unsustainability. It was estimated for the year 1998 that Europe produced about 6 million tons of waste electrical and electronic equipment (WEEE), in 2005 the WEEE arising was about 8.3 and 9.1 million tons being 4 % of the municipal waste and expecting to grow annually between 2.5 and 2.7 % reaching about 12.3 million tons in 2020. In Europe, there are several directives and regulations that aim to stimulate WEEE production, recycling and disposal such as the WEEE Directive [1]. The existence of such directives has clarified the horizon to develop a new generation of products and to develop more safe recycling processes in Europe. However, the path is still long to cover non-European electronic devices and have reliable recycling processes.The world has moved from relatively simple devices with few elements to incredible complex technologies including a large variety of elements. These elements are used as chemical compounds, as metal alloys and in some special cases as pure metal. Therefore, the new electronic devices represent due to their complexity and miniaturization a real challenge for the end-of-life product processers.The wide spectrum of elements in WEEE goes from base metals, precious metals, critical metals, different types of plastics, to some harmful elements. The so-called critical metals are used mostly in scarce quantities and are distributed in different components like printed circuit boards PCBs (e.g., platinum group metals (PGMs), precious metals (PMs), Sb, Ta, rare earth elements (Ta, Nd), Fe, Al, Cu, Pb, Ni, Sn, As, Ba, Br, Bi); liquid crystal displays LCD screens (e.g., indium as indium tin oxide ITO), light emitting diode LED (e.g., Ga, In and REs (Gd, Ce, Tb, Eu, Y, La, Sm, Lu, Tm, Dy), getters (e.g., W, Ta), fluorescent powders (e.g., La, Tb, Eu, Y, Ce), hard disks (e.g., PGMs), flame retardants (e.g., Sb), CRT glass (e.g., Sb) and batteries (e.g., Co, REs like Ce, LA, Nd, Pr) [2]. Quantities of base metals and precious metals vary from time to time according to their applications. Challenges in...