By Faridat Salifu
Discarded computers and electronic devices could become an important source of precious metals after scientists at ETH Zurich developed an experimental method for recovering gold from electronic waste.
The research highlights the growing potential of treating e-waste as an “urban mine”, where valuable materials contained in obsolete electronics can be recovered and returned to the economy instead of being discarded.
The scientists developed a porous protein-based aerogel that can selectively capture gold ions from a solution containing a mixture of metals extracted from electronic waste.
To test the technology, the researchers processed components from 20 discarded computer motherboards, dissolving the recovered material in an acidic solution to release different metal ions.
When the protein-based aerogel was introduced into the solution, it selectively bound the gold ions, allowing the researchers to separate the precious metal from the other materials.
The recovered gold was then converted into flakes and melted into a solid nugget weighing about 450 milligrams.
Analysis showed that the nugget contained 91 per cent gold and nine per cent copper, corresponding to approximately 21 to 22 carats.
The researchers also recorded a gold absorption capacity of 166.7 milligrams per gram of aerogel, demonstrating the material’s ability to concentrate gold from complex mixtures of metals.
The development could help shift the perception of electronic waste from an environmental burden to a potential source of valuable resources, particularly as obsolete computers and electronic devices continue to accumulate.
Gold recovery from electronic waste can be energy-intensive and may involve chemicals capable of generating hazardous waste and harmful emissions, creating environmental and health concerns when poorly managed.
The ETH Zurich approach could therefore contribute to efforts to make precious-metal recovery more resource-efficient while reducing the need to extract new materials.
An economic assessment conducted as part of the research further indicated that, under the study’s assumptions, the combined cost of sourcing materials and energy for the recovery process was substantially lower than the value of the gold obtained.
The findings point to a wider opportunity for e-waste recycling to support a circular economy by recovering valuable materials from obsolete electronics and reducing the amount of potentially useful resources lost to the waste stream.
Source :ELE Times
