*Article* **Electronic Waste Low-Temperature Processing: An Alternative Thermochemical Pretreatment to Improve Component Separation**

**Juliana S. S. Oliveira, Ronald R. Hacha, Felipe S. d'Almeida, Caroline A. Almeida, Francisco J. Moura, Eduardo A. Brocchi and Rodrigo F. M. Souza \***

> Department of Chemical and Materials Engineering, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil; juliana.sette@yahoo.com.br (J.S.S.O.); rojas@esp.puc-rio.br (R.R.H.); felipe\_dalmeida@hotmail.com (F.S.d.); caroline.azvdo@gmail.com (C.A.A.); moura@puc-rio.br (F.J.M.); ebrocchi@puc-rio.br (E.A.B.)

**\*** Correspondence: rsouza@puc-rio.br

**Abstract:** 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.

**Keywords:** low-temperature processing; WEEE (waste of electric and electronic equipment) recycling; materials separation; process characterization; SEM/EDS
