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Delamination
Material
Separation/Extraction/Purific
ation
Metal
Glass
Si cells
Chemical etching
Clean wafers
Retired PV
modules
Thermal decomposition
Physical separation
Fig. 9.5 PV recycling process
(3) Chemical process: The chemical process identifies and separates the metal fraction and glass & plastic fraction through solvent treatment. The glass and plastic
are discarded separately, and metal fractions are sent to the metal refinery for
recovery of metals.
In all the three processes, the silicon metal recovered is separated and further
converted into silicon wafers, also called slice or substrate (A slice of silicon
semiconductor mainly used for fabrication of integrated circuits). Pyrometallurgical and hydrometallurgical techniques are used in the metal refinery for the purification of metals and to obtain metals such as silver, aluminium, copper from the
supplied waste. These metals can be further used in many domains depending upon
the availability and degree of purity.
Other processes that could be used in the recycling process are given in the
Table 9.3.