Which E-waste Contain Which REEs?
Waste electrical and electronic equipment (WEEE) constitutes an important resource for rare earth elements (REEs). Waste liquid crystal displays (LCDs), spent batteries, spent light emitting diodes (LEDs), spent fluorescent lamps (SFLs), waste printed circuit boards (PCBs), spent cathode ray tubes (CRTs) and waste hard disk drives (HDDs) are the fastest growing WEEE and contain many critical rare earth elements and precious elements.
Indium is one of the rare elements and often found in LCD panels in the electronics industry. LCDs have replaced CRTs in recent years due to their lower power consumption capacity. Hence of its unique properties, indium is used as indium-tin-oxide in LCD panels. About 70% of the total Indium consumption consists of indium-tin-oxide. However, the amount of indium oxide in Dzhalindite ore, which is the primary source of indium, is around 0.25 ppm. Therefore Spent LCDs are a serious secondary source of indium.
Rechargeable batteries are called lithium ion batteries (LiBs) and consist of lithium and cobalt. LiB batteries are the most used type of battery. It is widely used in portable electronic devices such as cell phones, laptops, recorders, cameras and MP3 players. Due to its wide usage area, its consumption is also increasing and since cobalt is one of the critical elements, Li-Batteries should be seen as a secondary resource.
NiMH (Nickel-Hydride) Batteries
NiMH (nickel-hydride) batteries are also a valuable material in terms of the elements they contain mainly cerium, lanthanum, praseodymium, and neodymium. The spent NiMH (nickel-hydride) battery scraps constitute a serious secondary resource for cobalt and rare earth elements. It is used as a power source in electronic devices such as digital cameras, electric vehicles, mobile phones. Spent nickel-metal hydride batteries contain 32–47% Nickel, 2–5% Cobalt and 8–12% mischmetal consisting of Lanthanum, Cerium, Praseodymium, and Neodymium.
Spent Fluorescent Lamps (SFLs)
Fluorescent lamps use mixtures of green, red and blue phosphors to create white light. these phosphors contain one or more rare earth elements. The rare earth elements Cerium, Europium, Lanthanum, Terbium and Yttrium commonly used in led phosphors.Yttrium and Europium rare earth elements are present in the inner tube wall to absorb radiation.
SFLs offer opportunities for REE recycling, re-use of phosphorus, separation of different types of phosphorus, and recovery of rare earth metals from phosphors.
Fluid Catalytic Cracking (FCC) Catalyst
FCC Catalyst has an important place in the petroleum refinery and petroleum chemical industry. Contains Lanthanide and Cerium rare earth elements in its structure. Cerium content in the FCC catalyst is about 0.2–0.3%. Hence, it is important secondary source potential for cerium.