Researchers devise green method of gold extraction from scrap

With the help of a new solvent method, gold can be extracted from recycled materials in a more eco-friendly way, reports a research.

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, said a press release issued by the University of Helsinki quoting an article published in the scientific journal Angewandte Chemie .

“Small amounts of gold are often used in the electronics industry, and recovering it is important from the viewpoint of recycling,” said Professor Timo Repo of 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,” said Eeva Heliövaara, a doctoral student at the University of Helsinki and a co-author of the article.

There are small amounts of gold in computers, phones, and many other devices, which end 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 the scrap materials with the help of cyanide.