Scientists from the Swiss Higher Technical School of Zurich made a breakthrough in the field of processing electronic waste rich in precious metals. The team of researchers, led by Professor Raffale Mezzang, managed to extract gold using inexpensive and environmentally friendly material – a by-product of the dairy industry, serum protein.
Traditional methods of processing electronic scrap are very energy-intensive and require the use of expensive equipment for extracting precious metals. The new development is able to extract metal ions from a solution containing ionized waste.
The processing process is as follows: first, the scrap is dissolved in a special acid bathtub for the release and ionization of the metals contained in it. Then, a peculiar protein sponge is placed in the resulting solution. Thanks to the unique properties of this sponge, the ions of various materials adhere to it and firmly hold it, with gold ions doing this with the greatest efficiency.
After the ions of metals were absorbed into the protein sponge, it is heated to a certain temperature. As a result of heating, gold particles are separated in the form of flat flakes, which can be easily assembled and melted into compact ingots of a high sample.
During a series of experiments, scientists managed to extract an impressive amount of gold – about 450 milligrams of precious metal from only 20 motherboards. The resulting gold nugget resulted in 91% pure gold and 9% copper, which corresponds to a sample of 22 carats.
The amazing discovery was that the total cost of the raw materials used (serum protein) and energy costs are 50 times lower than the cost of the extracted metal at current market prices. If this method is used in mass production, it will be able to radically reduce energy consumption at processing plants due to the completely organic nature of the process.
The team of Professor Mezzang is not going to dwell on what has been achieved. Scientists will continue experiments, as well as work on commercialization. They hope to offer their innovative solution to interested companies working in the processing area.
In addition, researchers will check whether other inexpensive and easily accessible by-products or food industry waste can be used.
At present, the electronic waste disposal industry is rapidly gaining momentum, offering startups in this area the ability to earn up to $85,000 daily only for the processing of gold and copper. As the industry is further growing in the coming decades, the development of Metzang and its colleagues will allow companies to significantly optimize processes and reduce costs.