A new gold extraction technique is more sustainable and promises to reuse the precious metals used in electronic products.
In 2022, humans are estimated to produce 62 million tons of electronic waste-enough to fill more than 1.5 million garbage trucks. This value represents a 82% increase compared to 2010 and is expected to reach 82 million tons in 2030.
This electronic waste includes old portable and mobile phoneswhich contain precious materials like gold. Less than a quarter of these waste is properly collected and recycled. However, a new technique developed to safely and sustainably extract gold from electronic waste can help change this reality.
The new gold extraction technique, described in an article in the Nature SustainabilityIt can also make gold mining on a small scale less toxic to people – and for the planet.
GLOBAL GROUND GROWN
Gold has played a crucial role in human life over the centuries, either as currency or as a means of artistic expression and fashion. Currently, it is essential in modern industriesincluding electronics, chemical industry and aerospace sector.
However, the growing search for this precious metal has significant environmental consequences. Deforestation and the use of toxic chemicals are two examples. In industrial mining, the – highly toxic cyanide is widely used to extract gold from the ore. Although cyanide can be degrade, its use represents risks to wildlifeand toxic waste dams represent a threat to the environment.
In artisan mining, mercury is often used. Gold reacts with mercury forming a dense amalgam, which is then warmed to vaporize mercury and recover gold. This practice is the largest source of mercury pollution in the world and is dangerous for both miners and the environment. New solutions are therefore necessary.
A safer alternative
The interdisciplinary team of scientists and engineers has developed a new technique to extract gold from ore and electronic waste. The goal was to create a safer alternative to mercury and cyanide, reducing the impacts on health and the environment.
Although there are already techniques without cyanide or mercury, many have limitations in terms of performance, scale, cost and cover only part of the process. The new approach considers the sustainability throughout the cycle of extraction, recovery and refinement.
The authors used trichloroisocianuric acid – A common chemical in the treatment of water and pool disinfection – activated with salt water to turn gold into a soluble form. To recover gold, they developed a sulfur -rich polymeric adsorbent capable of selectively isolating gold, even in the presence of other metals.
This polymer is produced from elementary sulfuran abundant byproduct of the oil industry. Scientists were able to regenerate and recycle both the leaching chemist and the polymer, and purify the water used in the process.
A new technique was also created that allows “Undo” the polymer After capturing the gold, converting it back to its original mononer, ready to be reused-an important step for a circular economy.
A long and complex path
In the future, there is a plan to collaborate with industry, government and non -profit organizations to test the technique in handcrafted mining operations. The long term objective is to provide a robust and safe method gold extraction, without resort to toxic chemicals such as cyanide and mercury.
Challenges include polymer scale production and the economic viability of the process. You First results are promisingbut there is still a long and complex path until these new techniques can replace current practices.
The biggest motivation is Support the millions of artisanal miners which depend on mercury to extract gold by offering them a safe and economically viable alternative. At the same time, simple and safe methods such as this can boost urban recycling of precious metals.
Success in gold recovery from electronic waste can also reduce the need for primary mining – and thus minimize its environmental impact.
