Vol.:(0123456789) 1 3 Journal of Sustainable Metallurgy https://doi.org/10.1007/s40831-019-00242-w RESEARCH ARTICLE Evaluation of Fluidization Process for Recovery of Metals from Discarded Printed Circuit Boards Amit Barnwal 1  · Nikhil Dhawan 1 Received: 15 January 2019 / Revised: 25 July 2019 / Accepted: 27 July 2019 © The Minerals, Metals & Materials Society 2019 Abstract Technological advancements and the ever-increasing demand for the latest electronic gadgets lead to the huge generation of waste. Printed circuit boards are key connecting components of any electronic device, and the presence of signifcant metal- lic values such as copper can be regarded as a valuable secondary source. The discarded printed circuit boards are grounded to − 1 mm size and they consist of 30–40% metal values and 60–70% plastic–organic fraction. Due to the presence of a high amount of plastics in the feed, separation between the plastic and the metallic fraction is necessary for efective recycling. In this study, air and water-based fuidization processes are experimentally investigated for the separation of metallic val- ues. Combined fuidization concentrate yielded a grade of about 90% with an overall recovery of 35%. It was found that the combination of air and water fuidization is a promising route to recover metals from electronic scrap as it is cost-efective and environment-friendly. The underfow fraction obtained consists of 87% metal fraction (Al, Cu, Zn, Pb, and Sn) and can be further used in alloy-making applications. Keywords Printed circuit board · Recycling · Fluidization · Copper · Recovery · Grade Introduction Technological advancements lead to increased use of elec- tronic equipment in diferent sectors such as information technology and health care. However, the increase in the consumption of electronic goods leads to the massive gen- eration of electronic waste with time. Electronic waste is the source of various toxic elements like As, Bi, Be, Cd, Pb, Hg, and polychlorinated biphenyls, polybrominated biphe- nyls, tetrabromobisphenol A, polybromo diethyl ether, which leads to various hazardous environmental and health issues [1–3]. The printed circuit board (PCB) constitutes about 6% of the total e-waste generated [2, 3]. PCB is the key component of any electronic gadget which is mechanically supported and electrically connected. PCB contains base metals (Cu, Al, Fe, Zn, Sn, and Pb), trace amounts of high-value metals (Au, Ag, and Pt) and a majority of non-metallic values (Br, Al 2 O 3 , SiO 2 , and CaO). PCB is composed of two or three layers of non-conductive substrates, where copper sheet intact along with epoxy resins and fber glass is chemically coated with bromine epoxy layer to keep the circuit intact. Generally, non-metallic fractions are manufactured using non-conductive substrate, such as epoxy resin, and glass- woven reinforced plastics and ceramics or using cellulose paper reinforced with phenolic resin [4, 5]. Some formal recycling processes are being used world- wide for processing electronic waste and include pyrometal- lurgy, hydrometallurgy, and physical separation processes. In pyrometallurgy, waste printed circuit boards are treated at high temperature under an argon atmosphere to sepa- rately recover the valuable material [5, 6]. A large quantity of waste liquid efuents is produced during the metal dis- solution and requires proper disposal. Pyrolysis, gasifca- tion, combustion, supercritical fuid depolymerization are some of the other chemical recycling processes adopted in a laboratory set up [7, 8]. Physical benefciation process makes uses of physical characteristics and avoids the use of high temperature as well as chemicals. The recovery of metals from PCBs by physical separation processes includes The contributing editor for this article was Bernd Friedrich. * Nikhil Dhawan ndhawan.fmt@iitr.ac.in 1 Department of Metallurgical & Materials Engineering, Indian Institute of Technology, IIT-Roorkee, Uttarakhand 247667, India