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One of the technical challenges with the recovery of valuable materials from end-of-life (EOL) photovoltaic (PV) modules for recycling is the liberation and separation of the materials. We present a potential method to liberate and separate shredded EOL PV panels for the recovery of Si wafer particles. The backing material is removed by submersion in liquid nitrogen, while the encapsulant is removed by pyrolysis. After pyrolysis, separation of the liberated particles (i.e., Si wafer and glass) is carried out by using particle size and shape with mechanical screening. Using this robust approach, a Si wafer grade of 86% and a recovery of 88% were achieved.
INTRODUCTION
Renewable energy systems have grown rapidly in the past decade, and part of that growth has been witnessed by the photovoltaic industry.1 For example, the global installed photovoltaic (PV) capacity grew from 40 GW in 2010 to 227 GW in 2015, making up 12% of the total renewable energy capacity.2 The cumulative installed PV capacity is expected to continue growing, with projections up to 4512 GW by 2050.3 As the production and installation of PV modules grow, so does the amount of endof-life (EOL) PV modules. Most PV modules installed have yet not reached their EOL due to their long lifespans of 25-30 years. However, there is expected to be a dramatic influx of PV panel waste around 2030,3-6 by when it is expected to be around 1.7-8 million tons, while by 2050 it is expected to be between anywhere between 60 and 77 million tons.3 The waste from EOL PV panels contain a number of valuable and recyclable metals and materials.7 Studies on the recovery and recycling of these materials show that energy and environmental savings can be realized,8,9 demonstrating their importance to photovoltaic technology sustainability.
The low disposal rates of PV modules have resulted in a lack in the development of a recycling process. Most EOL PV modules are currently being disposed of in landfills or as hazardous waste, depending on the module type and applicable laws.4,5 In terms of policy on the disposal of EOL PV materials, there are presently no federal regulations in the U.S.; however, some states have acted (e.g., ESSB 5939,10 Bill S2837A,11 and California SB 489).12 In the case of hazardous...
