This is how one can extract gold from e-waste using old milk
Sat April 20 2024
Scientists at ETH Zurich have developed a revolutionary method to extract gold from electronic waste using a milk-derived aerogel. This sustainable approach offers a greener alternative to traditional methods, utilizing a natural byproduct and reducing environmental impact. The process, which yields highly pure gold, exemplifies the principles of circular economy and responsible waste management. This innovation has the potential to transform the recycling industry and pave the way for sustainable resource recovery.
In a world increasingly concerned with sustainability and the environmental impact of waste, a revolutionary discovery has emerged from the laboratories of scientists: the extraction of gold from electronic waste (e-waste) using old milk. This innovative method not only offers a solution to the growing problem of e-waste but also presents a sustainable approach to resource recovery.
E-waste, consisting of discarded electronic devices like computers, smartphones, and televisions, is a treasure trove of precious metals, including gold. Traditionally, extracting these metals has involved processes that are costly, energy-intensive, and harmful to the environment. However, researchers at ETH Zurich in Switzerland have developed a groundbreaking technique that utilizes a milk-derived aerogel to recover gold from e-waste.
The process begins with whey protein, a byproduct of the cheese-making industry. Scientists transform this protein into a low-density aerogel—a material known for its high porosity and surface area. The aerogel acts like a sponge, selectively adsorbing gold ions from a solution containing various metals. Remarkably, the aerogel can capture up to 93 percent of the gold while leaving behind less than 10 percent of other metals.
Once the gold ions are adsorbed onto the aerogel, they are reduced to form metallic gold. This is achieved by dissolving computer motherboards in aqua regia, a potent mixture of nitric acid and hydrochloric acid, which releases gold ions into the solution. The aerogel then snatches these ions from the mixture, and upon heating, frees the gold, turning it into a small, highly pure nugget.
The beauty of this method lies in its simplicity and sustainability. The aerogel is made from a natural byproduct, and the process of making it is relatively inexpensive. Raffaele Mezzenga, one of the lead researchers, highlights the cost-effectiveness, stating, "The value of the gold we recover is 50 times the value we invest to transform the protein into this sponge". Moreover, the gold extracted is about 91 percent pure, equivalent to 21 to 22 carats.
This discovery has significant implications for the recycling industry and the environment. It offers a greener alternative to conventional gold recovery methods, which often rely on synthetic chemicals that can be damaging to the ecosystem. By using a biodegradable and readily available material like old milk, the process aligns with the principles of circular economy and responsible waste management.
The potential of this technique extends beyond gold recovery. The team at ETH Zurich is exploring other food waste proteins, such as keratin and those from tofu production, to recycle rare earth metals. This could pave the way for a new era of material recovery, where waste is not seen as an endpoint but as the beginning of a new cycle of use. The method of extracting gold from e-waste using old milk challenges the traditional notions of waste and resource extraction, offering a glimpse into a future where technology and nature work hand in hand. As we move towards a more sustainable world, such innovations will play an important role in shaping our approach to resource utilization and environmental stewardship.
Source: https://timesofindia.indiatimes.com/