*Article* **Gravity and Electrostatic Separation for Recovering Metals from Obsolete Printed Circuit Board**

**Camila Mori de Oliveira 1, Rossana Bellopede 1,\*, Alice Tori 2, Giovanna Zanetti <sup>1</sup> and Paola Marini <sup>1</sup>**


**\*** Correspondence: rossana.bellopede@polito.it

**Abstract:** This study proposed an evaluation of enrichment processes of obsolete Printed Circuit Boards (PCBs), by means of gravity and electrostatic separation, aiming at the recovery of metals. PCBs are the most important component in electronic devices, having high concentrations of metals and offering a secondary source of raw materials. Its recycling promotes the reduction in the environmental impacts associated with its production, use, and disposal. The recovery method studied started with the dismantling of the PCB, followed by a comminution and granulometric classification. Subsequent magnetic, gravity, and electrostatic separations were performed. After the separations, a macroscopic visual evaluation and chemical analysis were carried out, determining the metal content in the concentrate products. The results obtained from gravity separation showed a product with metallic concentrations of 89% and 76% for particle sizes of 0.3–0.6 mm and 0.6–1.18 mm, respectively. In electrostatic separation, the product obtained was 88% for the lower particle size (<0.3 mm) and 62% for particles sizes >1.18 mm.

**Keywords:** PCB; recycling; metal recovery; mechanical pre-treatment

**Citation:** de Oliveira, C.M.; Bellopede, R.; Tori, A.; Zanetti, G.; Marini, P. Gravity and Electrostatic Separation for Recovering Metals from Obsolete Printed Circuit Board. *Materials* **2022**, *15*, 1874. https:// doi.org/10.3390/ma15051874

Academic Editors: Dimitra Vernardou and Damon Kent

Received: 2 December 2021 Accepted: 24 February 2022 Published: 2 March 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).
