Multi-Layer Ceramic Capacitors in Lighting Equipment: Presence and Characterisation of Rare Earth Elements and Precious Metals

Abstract

In this study, multi-layer ceramic capacitors (MLCCs) detached from lighting sector's waste
 electrical-electronic equipment (WEEE) are characterised for the presence of rare earth elements
 (REEs) and precious metals (PMs). Their digestion was carried out with HNO3 & aqua regia on a
 heating plate and characterised with the use of inductively coupled plasma optical emission
 spectroscopy (ICP-OES) & scanning electron microscopy with energy dispersive X-ray spectroscopy
 (SEM-EDX). The contents of REEs and PMs are 0.84 wt% and 0.60 wt%, respectively, and create an
 economic stored value in MLCCs that is essentially defined by PMs of 98.67% and by Pd 78.37%.
 The content of the main elements is: Nd 0.366 wt%, Y 0.220 wt%, Dy 0.131 wt%, Ag 0.467 wt%,
 and Pd 0.105 wt%. The results confirm the need of selective removal and separate recycling process
 of MLCCs from WEEE drivers.