There's a component of our smartphones a which we usually don't pay too much attention to and which usually goes completely unnoticed once we insert it into the cellphone, and it's none other than the chip or la scheda SIM. The famous ticket that we all have in our terminal opens the doors of the 4G connection and mobile coverage, although, unfortunately, it is also one waste that in the years ends up being thrown away. However, as the famous saying goes, "Some waste, others treasure".
To get some context, the annual production of e-waste is around 50 million tons, according to a study. Of these 50 million tons (which, to give you an idea, is the weight of 279.720 Boeing 747s) only 20% is recycled. The rest goes to e-dumps where it will remain until the end of time or until the passage of time itself degrades it. What comes first.
Today we echo a rather curious new recycling technique whose protagonists are none other than the SIM card. As reported by IFLScience! , a method for recycle metal SIM chips in a simpler and cheaper way by mining gold which is in them.
Pull the gold out of the SIM card chips
The technique to extract gold from SIMs uses ultrasound and cavitation *. The first thing you do is coat the SIM with a very thin layer of a surfactant compound, then repeat the process with another type of surfactant, and finally immerse the SIM in water. The surfactant compounds help reduce the tension between the SIM surface and the water. In this way, through the ultrasonic waves, bubbles are created which increase pressure and temperature. This causes the gold particles detach from the SIM card and become trapped in these bubbles for subsequent collection and recycling.
This process is not new, in fact it is already used to extract other metals. The problem is that it is an expensive and polluting process. The main novelty of this new technique is that, according to Dale Huber, researcher at Sandia National Laboratories (Albuquerque, Mexico), it has a reduced environmental impact and it can help address the e-waste problem without the remedy being worse than the disease.
To add a few figures, every year $ 20 billion worth of gold, silver, copper, platinum and palladium are disposed of in electronic waste. With this technique, the rate di Recycling of these materials could be increased for their subsequent reuse in new devices. Not only could this reduce manufacturing costs, but it would help reduce the huge environmental impact of extracting these types of materials to make components.
* Cavitation: formation of vapor or gas filled cavities in a moving liquid. It occurs when the pressure in a point of the liquid is lower than the vapor pressure.
Source: Newscientist
