Abstract:
Photovoltaic (PV) technology for renewable energy utilization is constantly growing throughout the world. This widespread application is going to determine the disposal of large amounts of wastes (as end of life panels): only in Europe about 500,000 ton/year are expected in the next 20 years. European Union issued the Guideline 2012/19/EU in order to fix rules about end of life photovoltaic panel's treatment establishing both collecting rates and minimum recovery targets.
Currently the dominant PV technology uses crystalline silicon (monocrystalline and polycrystalline) as semiconductor, but the thin film photovoltaic modules using cadmium telluride (CdTe), amorphous silicon, Copper Indium Gallium Selenide (CIGS) and Copper Indium Selenide (CIS) are recently getting much more importance. Wastes of PV installations are secondary raw materials which could be treated in order to recover glass and Al, but also other metals such as Cu, Ti, Ag, Te, In, Se, Ga, along with plastic and metallic components of electronic equipment.
Many recent efforts were devoted to the treatment of end of life panels, but only two full scale processes were developed for crystalline silicon modules (Deutsche Solar) and CdTe panels (First Solar). Furthermore, recent developments concerned with new technologies are designed for treating together more kinds of photovoltaic panels by automated processes. In this lecture, a picture of the PV world in terms of market, typology, waste dynamics and recoverable materials will be given. A detailed description of full scale processes will be reported evidencing products and yields of recovery. A case study of process development for the simultaneous treatment of different kinds of PV panels will be presented. In particular, experimental results in lab and pilot scale will be described regarding the development and optimization of a process including both physical pre-treatment and hydrometallurgical recovery of target metal concentrates.
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