Pulse laser recovery of high-purity colloidal silver spheres from end-of-life crystalline silicon solar panels

초록

Crystalline silicon photovoltaic (c-Si PV) modules, regarded as first-generation solar cells, are expected to generate a significant volume of end-of-life materials in the coming years due to their limited lifecycle. We propose a novel recycling process to recover silver from spent c-Si PV modules, producing high-purity silver spheres through photoreduction using a nanosecond pulsed laser. In detail, a leaching efficiency of similar to 100 % was shown with an optimized lixiviant concentration (1 M HNO3), temperature (70 degrees C), time (60 min), and solid-liquid ratio (75 g/L). To recover high-purity silver from the leachate, interfering ions other than silver were removed through pH adjustment, and the loss rate of silver was only 1.9 %. High-purity spherical silver particles were recovered by irradiation with a nanosecond pulsed laser at 100 mJ for 60 min to the Ag2O suspension, which was produced by adding NaOH to the purified leachate. The final recovery efficiency of silver was similar to 98 % through leaching, impurity removal, and laser reduction from the waste PV cell. A preliminary life cycle assessment indicated that the process has lower energy consumption and environmental impact than conventional techniques, though economic performance still requires improvement.

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