UNSW Sydney engineers have developed a new, more effective way of recycling solar panels,
UNSW Sydney engineers have developed a new, more effective way of recycling solar panels, which can recover silver at high efficiency. In tests, using their process, the researchers were able to extract 99 per cent of silver from a solar cell for potential reuse.
Recycling solar panels thoroughly has proven difficult up to now since the individual parts, such as glass, silicon, metals, wiring and plastic, are integrated in such a way that makes them hard to separate.
Prof. Shen’s team have been working for nearly three years on developing their new processes, which integrate conventional methods with a very highly abrasive separation system using the addition of sieving aids.
The first existing step to recycle PV panels involves the removal of large components such as the aluminium frame and glass sheets to just leave the solar cell.
“The next step is the crushing the panel and separation of material inside the solar cell and that is currently one of key bottlenecks for the whole system,” says Prof. Shen.
The team discovered that using stainless steels balls as a sieving add provided the most optimal solution for the process.
The key to new process is the addition of the sieving aids which help to crush the solar cells into smaller particles allowing a better separation of all the components. That makes it much easier to recover important elements such as the silver contained in the solar cells.
The entire crushing and sieving process, which occurs inside a vibrating container, takes only around 5-15 minutes to effectively separate 99 per cent of the PV materials.
Once the material has been separated using the new patented process, the team can employ a traditional chemical leaching, as well as precipitation to extract the specific elements such as pure silica and silver.
The ProMO research team at UNSW calculate that between 5-50 million kilograms of silver could potentially be recycled from the cumulative waste by 2050 using their process, given that the equivalent of around 0.64kg of silver per tonne of PV waste has been recovered in tests.