Finnish scientists use cooking oil and peroxide to recover silver from electronic waste

Researchers in Finland have developed a method that uses common cooking oils and hydrogen peroxide to extract silver from electronic waste, a process they say could offer a lower‑toxicity alternative to conventional recycling techniques.

Authors at the University of Helsinki and the University of Jyväskylä published the work in the Chemical Engineering Journal, reporting that fatty acids found in vegetable oils such as sunflower or olive oil can interact with silver ions from circuit boards and connectors. When combined with hydrogen peroxide and warmed slightly, the mixture dissolves silver; subsequent treatment with ethyl acetate produces solid elemental silver.

The team used computational modelling to investigate how fatty acids stabilize silver ions, and laboratory tests showed the method can selectively target and recover silver while leaving other metals in place. The process reportedly converts silver‑coated components into pure silver powder. Ethyl acetate was used as the extracting solvent; it is commonly viewed as less toxic than many industrial solvents used in metal recovery.

The approach contrasts with many current recycling and hydrometallurgical techniques that rely on strong mineral acids, cyanide‑based reagents or high‑temperature smelting — methods that can generate toxic effluents, hazardous air emissions or pose occupational risks for workers. By using organic fatty acids and an oxidant already present in many labs and households, the Finnish researchers say the method reduces hazardous byproducts and allows reuse of reagents.

Silver is a critical material in electronics, renewable energy technologies and medical devices, but it is poorly recycled. Industry estimates and academic reviews indicate that less than one‑fifth of silver is recovered from end‑of‑life products. Demand has risen while primary supply growth has been limited, contributing to a significant increase in silver prices over recent decades.

The authors emphasise the selectivity of the process: stabilisation by fatty acids and controlled reduction permit recovery of silver without co‑processing large quantities of other metals. They also report that simple photochemical steps can assist in the final conversion of dissolved silver into elemental form, and that the principal organic reagents can be reclaimed for repeated use in multiple cycles.

Laboratory demonstrations processed silver‑coated connectors and printed circuit board fragments to yield metallic silver powder. The researchers describe the technique as scalable, noting that it may be applicable to small‑scale urban mining operations and industrial recyclers who seek lower‑impact alternatives to conventional wet chemistry and pyrometallurgy.

Environmental and policy analysts say technological advances that make recovery of precious metals from e‑waste safer and more economical could reduce pressure on mining, lower lifecycle emissions for electronics and renewables, and improve conditions in informal recycling sectors. However, adoption will depend on process economics, regulatory approval for solvents and reagents, worker safety protocols, and integration with existing recycling streams.

The researchers caution that the method remains under refinement. Additional work is needed to assess performance across the wide range of electronic device types, to quantify recovery yields and reagent lifetimes at scale, and to evaluate full‑system environmental impacts compared with established techniques. If those studies confirm laboratory findings, the method could offer recyclers and manufacturers a way to recover valuable silver with fewer hazardous byproducts, keeping material in use and reducing demand on mined supplies.