The recovery of minerals from recycled materials, or so-called ‘urban mining,’ is an expanding industrial branch. The amount of gold in scrapped electronics, for example, may be up to 10-100 times that of ore.
There are small amounts of gold in computers, phones, and many other devices, which ends up being burned along with the scrapped devices.
The gold is separated chemically from the ashes, but the chemicals being used currently are very damaging to the environment. In developing countries, the gold is recovered with the help of quicksilver in inhumane conditions in sweatshops. Another environmentally risky method is dissolving with the help of cyanide.
– Small amounts of gold are often used in the electronics industry, and recovering it is important from the viewpoint of recycling, says Professor Timo Repo from the Department of Chemistry at the University of Helsinki, who has developed the new method.
Now, researchers have succeeded in using an organic solvent to extract gold, using sulphuric acid as an auxiliary and hydrogen peroxide as an oxidant. So far, the method has only been tested in lab conditions.
– Once the basic phenomenon has been observed, it opens up possibilities for a wider set of applications, Eeva Heliövaara, a doctoral student from the University of Helsinki, says.
Pyridinethiol‐Assisted Dissolution of Elemental Gold in Organic Solutions: Dr. Minna Räisänen, Eeva Heliövaara, Dr. Feda'a Al‐Qaisi, Dr. Mikko Muuronen, Aleksi Eronen, Henri Liljeqvist, Dr. Martin Nieger, Dr. Marianna Kemell, Karina Moslova, Dr. Kalle Lagerblom, Prof. Timo Repo. 29 October 2018, Journal Angewandte Chemie. https://doi.org/10.1002/anie.201810447
Professor Timo Repo
Doctoral Student Eeva Heliövaara
Science communicator Riitta-Leena Inki
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