The pace of expansion of solar installations is currently breathtaking. Worldwide, electricity yields are increasing by around 20% per year, which means that a very large number of photovoltaic systems will soon be in operation.
Instead of waiting a few more years until the mountains of obsolete solar cells begin to grow menacingly, it would be wise to start looking for solutions to a problem that is looming on the horizon. Just think of wind turbine blades, the subsequent recycling of which was not considered for a long time.
That’s why two Chinese universities published a recent study presenting a remarkably simple, fast and environmentally friendly method. In particular, the crystalline solar cell itself can be broken down into its original elements.
First, components such as the aluminum frame and the protective glass cover can be removed. Both of these can easily be melted down and reused.
The cell is then separated from the silicon, silver and aluminum through an etching process. Basically, salt water is used here, but with a very high sodium and potassium content. These two elements are also present in any mineral water.
This molten material is heated to approximately 200°C. The process only takes 180 seconds. Then, 98% of the silicon and 99% of the silver were removed from the semiconductor wafer. The copper, lead and tin can then be separated through a final electrolysis process. In the end, all that’s left is a pure silicon wafer.
Compared to previous methods, energy consumption would be reduced by a factor of 200. No toxic end products are produced, and all extracted elements and chemical compounds can be reused afterwards.
This is a significant advancement that could make solar systems even more sustainable. Many yogurt pots could be inspired by it.
