Brazil is the second largest producer of electronic waste in the Americas, with a production that grows each year and only 10% of it being treated in its own way. Additionally, given the typical chemical composition of this type of residue, it can be possible to recover valuable metals, such as copper, gold, silver, and platinum. Presently, Brazil does not have an industrial plant devoted to such extractive activity using electronic waste, with most of its treatment carried out abroad. The research hypothesis of this manuscript is that universities and their communities could develop sources of raw materials for such extraction processes and, therefore, deserve attention for the creation of collection points and partnerships. In this context, there is a need to understand this community behavior regarding the acquisition, storage, and disposal of electronic equipment, as well as information about topics related to electronic waste management and recycling. To implement such a study for the higher education community in Rio de Janeiro, a form was created covering several topics on the subject, which was disseminated among the teachers, students, employees, and family members of two main state universities. It was determined that the studied group has more than 16.96 million mobile phones in hibernation, in addition to other equipment, with an estimated stockpile value of USD 67.45 million for the studied group in the metropolitan area of Rio de Janeiro. If extrapolated to all of Brazil, this could be as high as USD 797.50 million for the studied group. This information will be used in future projects to assess the economic potential of an industrial plant dedicated to metal recovery in Brazil. However, the present study also identified an important lack of knowledge regarding proper waste disposal and solid waste policies among this well-educated group. It became clear that without appropriate information regarding collection points and knowledge on how to deal with obsolete devices, the access to this source of raw material could be a hinderance to future extraction projects in the area.

This work covers initially a general thermodynamics assessment regarding the zinc ferrite (ZnFe 2 O 4 ) behavior toward direct and reducing chlorination. Then, the use of alternative chlorination agents were also theoretically appreciated, before a set of experiments has been carried out with industrial residue (electric arc furnace dust). Besides identifying zinc ferrite (95.4 pct), the XRD analysis indicated the presence of ZnO (4.6 pct). Therefore, the main objective of the present work is related to a theoretical (thermodynamics) and experimental (kinetics) evaluation of the mentioned residue chemical behavior as submitted to chlorination methods. Several characterization methods were used, such as X-ray diffraction, scanning electron microscopy, X-ray fluorescence, mass spectroscopy (ICP-MS), and energy-dispersive X-ray spectroscopy (EDS). It was observed that zinc was present, mostly, in the form of zinc ferrite (franklinite). The thermodynamics study revealed that Zn has a more susceptible behavior regarding the oxides conversion into chlorides. However, this tendency is not necessarily associated with a selective reaction, as showed for the chlorination in the presence of carbon, as both iron and zinc chlorides formation is feasible. The experimental results have indicated that some reaction systems can be further studied in order to identify operational conditions that enable selective formations. So, it was observed that for the calcium chloride reaction conducted at 1273 K (1000°C) for 30 minutes, the iron content in the residue slightly increases (with 15 pct removal), whereas the zinc content decreases from 20 to 12 pct (53 pct removal), suggesting complementary studies where this possible selectivity could be even more determinant. Such results have also indicated that the direct action of chlorine at 1073 K (800°C) allowed complete removal of zinc, followed by conversion in the order of 40 pct in iron. Therefore, a complementary investigation over these alternatives is identified as a promising option in the field of electric arc furnace dust treatment, particularly when the Zn content is very low.

The production of electronic waste due to technological development, economic growth and increasing population has been rising fast, pushing for solutions before the environmental pressure achieves unprecedented levels. Recently, it was observed that many extractive metallurgy alternatives had been considered to recover value from this type of waste. Regarding pyrometallurgy, little is known about the low-temperature processing applied before fragmentation and subsequent component separation. Therefore, the present manuscript studies such alternative based on scanning electron microscopy characterization. The sample used in the study was supplied by a local recycling center in Rio de Janeiro, Brazil. The mass loss was constant at around 30% for temperatures higher than 300 °C. Based on this fact, the waste material was then submitted to low-temperature processing at 350 °C followed by attrition disassembling, size classification, and magnetic concentration steps. In the end, this first report of the project shows that 15% of the sample was recovered with metallic components with high economic value, such as Cu, Ni, and Au, indicating that such methods could be an interesting alternative to be explored in the future for the development of alternative electronic waste extraction routes.

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