Silicon: What Are We Recycling
When describing the recycling process for silicon as an elemental component of photovoltaic cells, let’s first understand what silicon is (and isn’t).
Silicon is a metalloid, with the properties of both metals and non-metals. Its greatest quality is probably its ability to conduct electricity, especially at high temperatures. Silicon’s potential as a semiconductor makes the element a familiar component in computer chips and solar panels.
What silicon isn’t though, is silicone.
Silicone is a polymer made of elements, usually silicon, carbon, hydrogen and oxygen. Instead of being a semiconductor, silicone is an electric insulator. As an insulator, silicone can also be found in computers, but to protect parts from electric currents instead of passing them. Generally liquid or a flexible plastic-like solid, silicone is used in medical implants, contact lenses, bandages, personal care items and much more.
While silicone can be recycled, it is not often included in the list of items that municipalities will pick up. Neither is silicon as it is used in solar panels, but environmentally compliant solar recyclers can handle the element at utility-scale levels.
Silicon Recycling Processes for Solar Panels
As a layer of semiconductors within the middle of a solar cell, silicon aids in the absorption of solar energy. This absorbed energy is sent through a circuit and is eventually captured as electrical current.
Silicon can be found in various types of photovoltaic cells, including monocrystalline, polycrystalline, amorphous silicon, and thin-film cells, making it a component in most of today’s solar panels.
Through a comprehensive process of demanufacturing, parts harvesting, recovery, and recycling, silicon can be effectively recycled from solar cells.
If You Can Recycle Silicon, Then What Does It Become?
Silicon is not often found free in nature – it is usually bound with other elements and mined both as sand or vein deposits. This means that to get the silicon used in solar panels and computer chips, the found minerals need to be processed for the extraction of silicon.
Since silicon is not found by itself, recycling solar panels is a great way to retain the mined element for new or refurbished photovoltaic cells. Recycled silicon has also been tested in lithium-ion batteries and could help the batteries store more energy, giving another use for this rarely-alone element.