Extracting gold from electronic waste suddenly becomes profitable with the help of whey protein
Researchers extracted metal components from 20 old computer motherboards and dissolved them in an acid bath to ionize or separate the metal into positive and negative ions. When protein fiber sponge is placed in a metal ion solution, gold ions will stick to it. Although other metals such as copper and iron can also be absorbed by sponges, the absorption efficiency of gold is much higher.
After absorbing gold ions, the protein fiber sponge is heated, reducing the ions into flakes and ultimately melting into gold blocks with a mass of about 500 milligrams. Analysis shows that gold nuggets are mainly composed of gold (90.8 wt%), with copper and nickel accounting for 10.9 wt% and 0.018 wt%, respectively. These findings indicate that the purity of gold nuggets is very high, equivalent to 21 or 22 carats.
In the paper, the researchers demonstrated the commercial feasibility of their method. The total cost of recycling 1 gram of gold from electronic waste, including the cost of raw material procurement and the energy cost of the entire process, is 50 times lower than the value of recycling gold.
And from an environmental perspective, this method is better. Recycling 1 gram of gold from electronic waste using traditional activated carbon generates about 116 grams of carbon dioxide, while protein fiber sponge has a lower carbon footprint, producing only about 87 grams of greenhouse gases. The main reason why the use of activated carbon has a significant impact on the environment is that it consumes more energy during the production process. This is mainly due to the use of non renewable fuels, coupled with the lower adsorption capacity of activated carbon compared to sponge.
Previous attempts to withdraw funds have their drawbacks, such as scalability. Due to whey being an animal protein, protein fiber sponges may cause greater damage to ecosystems than activated carbon. Therefore, researchers will explore whether plant-based proteins (such as those extracted from peas and potatoes) can replace whey.
The researchers plan to push this technology to the market. Although electronic waste is a promising starting source for extracting gold, they are also focusing on other sources, including industrial waste generated during microchip manufacturing or gold plating processes.
This study was published in the journal Advanced Materials.
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