With the decrease in the natural resources of precious metals and the increasing global demand for them, a team of Finnish researchers developed a revolutionary and environmentally friendly method for recycling silver from electronic waste using cooking oils.
This method depends on the use of fatty acids of common vegetable oils and light, and is to convert this increasing type of waste into a valuable source for this mineral, while avoiding dangerous and polluted chemical processes that dominate this industry today.
“In our new way, the materials used to treat silver are inexpensive and sometimes derived materials from waste. Therefore, their price is close to the price of already used operations,” says the lead author of the study, Anzi Zobank, a post -PhD, Helsinki University, in a special dialogue in Al -Jazeera Net.
Results were published the study The researchers conducted to extract the silver metal from electronic waste in the journal “Kimikal Ingering Journal”.
A precious metal under the request pressure
Silver is among the most used minerals in many fields, it is an essential component in the manufacture of components of computers and mobile phones, and is used in medicine for its anti -bacterial properties, as it is an essential component of the solar panels industry, and then its availability stimulates the shift towards more dependence on renewable and clean energies.
However, this wide spread led to an increased demand for this mineral, as it indicates Specialized reports To the global demand for silver exceeded the offer by 16% in 2023, while the price has risen 6 times over the past twenty -five years.
The high demand for silver also led to dwindling with exploitable natural reserves, which only left enough for about 20 years at the current extraction rate. However, the annual silver production of recycled sources is still relatively modest, as only 17% of the quantities of silver extracted in 2023.
One of the reasons that hinder the development of this ratio is the methods currently used to re -extract silver from waste that is expensive and contaminated at the same time. Thermal processes consume enormous energy and include burning waste at very high temperatures to extract minerals.
Chemical treatment methods to extract silver from waste produce dangerous chemicals such as cyanide known as its toxicity, nitric acid that causes erosion and harmful ammonia.
The extraction of one kilogram of this precious metal requires about 170 kilograms of dissolved cyanide in 500 cubic meters of water, which may cause this substance to leak into the sewers and raise the risk of a major environmental catastrophe, such as those that occurred in the Romanian -Roman areas in 2000 and Tianjin in China in 2015.
Cooking oils to separate silver
In the new study, a team of researchers from the University of Helsinki developed a radically different way to extract silver metal from electronic waste, characterized by being safe, sustainable and inexpensive.
The idea on which this innovative method is somewhat simple but amazing at the same time, and is to use fatty acids in vegetable oils to dissolve silver.
The researchers ’dissolution, according to what was stated in the study, relied on the most commonly unsaturated fatty acids such as oleic acid found in olive oil and linoleic acid in sunflower oil.
These materials are characterized by their abundance, as global production of vegetable oils exceeds 15 million tons annually, in addition to being biological and non -toxic decomposition and can be extracted even from waste, such as used cooking oil, which makes them completely compatible with the circular economy.
Zobank explained that the new method “works quantitatively using a slight heating, and then is characterized by low energy consumption and its high efficiency.”
The process takes place in moderate conditions, with light heating to 60 ° C and by adding non -harmful materials to accelerate the extraction of silver. The fatty acids play an essential dual role, as they form the liquid in which silver melts and their molecules install the newly formed silver ions, and this prevents them from interacting and preserving them in the solution.
The innovative method, according to the study, enabled the dissolution of up to 4.6% of the weight of silver in relation to the weight of the fatty acids used. This means that one kilogram of oils can dissolve 46 grams of silver, which is an enormous loading capacity compared to traditional solvents. The reaction speed using the new method was about twice the fastest traditional method used today.
The researchers have proven the efficacy of this innovative method on real waste, containing parts of silver -wrapped plastic from computer keyboards. From 13 grams of treated plastic, 677.8 mg of silver salts were extracted, and after reduction, 130.5 mg of pure metal silver was obtained, with a production rate of about 98%.
New horizons
This research opens promising horizons for electronic waste management and securing strategic metal supply.
In his conversation with Al -Jazeera Net, Anzi Zobank explained that the development of this technology “has now reached a high level of technological readiness, that has been validated in the laboratory.” But he added that “no attempt has been made to expand its scope yet, but we believe that by conducting more research, the process can be developed more.”
Dr. Zobank does not rule out that “more research leads to the discovery of appropriate conditions for extracting other noble minerals.” And he confirms that “the solar panels in particular will be the next goal of this process, given the size of their massive production, as well as the amount of quantities that dispose of them.”
As millions of tons approach the panels from the end of their shelf life in the coming decades, finding an effective way to restore the silver it contains will be very important.