The extensive deployment of photovoltaic (PV) modules
at an expeditious
rate worldwide leads to a massive generation of solar waste (60–78
million tonnes by 2050). A stringent recycling effort to recover metal
resources from end-of-life PVs is required for resource recovery,
circular economy, and subsequent reduction of environmental impact.
The recovery of metallic resources (silicon, silver, copper, lead,
and tin) from the first-generation PVs and critical elements (tellurium,
indium, selenium, and gallium) from second-generation PVs are mainly
targeted. This review systematically discusses the recycling literature
of both generations of solar cells, market value calculations, recycling
preferences, global trends, and the Indian perspective. The status
of PV module recycling on a commercial scale and academic research
efforts are discussed. The review systematically discusses the various
possible pretreatments and extraction/refining processes. The pretreatments
(physical, chemical, thermal, and hybrid processes) play a decisive
role in up-gradation, impurity removal, and metal recovery. The challenges
include homogeneous collection, process efficiency, holistic resource
recovery, and energy considerations. Toxicity characteristics of both
generations, life cycle assessment studies, recycling challenges with
proposed flowsheets, and a detailed future outlook are propounded
to develop a holistic metal recovery approach. In comparison, crystalline
Si PVs comprise the maximum economic value. One tonne of mixed PVs
(first and second generation) can yield ∼9.32 kg of Cu, ∼0.30
kg of Ag, ∼33.48 kg of Si, ∼1.12 kg of Sn, ∼1.12
kg of Pb, ∼4.9 g of Cd, ∼2.5 g of Te, and ∼3.4
g of In.
