Recycling of high purity selenium from CIGS solar cell waste materials
Artikel i vetenskaplig tidskrift, 2014
Copper indium gallium diselenide (CIGS) is a promising material in thin film solar cell production. To
make CIGS solar cells more competitive, both economically and environmentally, in comparison to other
energy sources, methods for recycling are needed. In addition to the generally high price of the material,
significant amounts of the metals are lost in the manufacturing process. The feasibility of recycling
selenium from CIGS through oxidation at elevated temperatures was therefore examined. During
oxidation gaseous selenium dioxide was formed and could be separated from the other elements, which
remained in solid state. Upon cooling, the selenium dioxide sublimes and can be collected as crystals.
After oxidation for 1 h at 800 C all of the selenium was separated from the CIGS material. Two different
reduction methods for reduction of the selenium dioxide to selenium were tested. In the first reduction
method an organic molecule was used as the reducing agent in a Riley reaction. In the second reduction
method sulphur dioxide gas was used. Both methods resulted in high purity selenium. This proves that
the studied selenium separation method could be the first step in a recycling process aimed at the
complete separation and recovery of high purity elements from CIGS.