Technology

New method for safer mining of precious metals such as gold

Researchers at the University of Notre Dame have invented a new class of molecules that can be used to simplify the process used to capture precious metals such as gold, platinum and palladium.

The study, published in the Journal of the American Chemical Society, shows that these new molecules were created in a specific shape and size that allow them to capture the precious metal ions. This unique molecular recognition property can be utilized for multiple applications – the most notable being gold mining.

“Today, most of the world’s mined gold is using an outdated 125-year-old process that processes gold with large amounts of poisonous sodium cyanide, which is extremely dangerous for mine workers and can cause environmental problems,” said Bradley D. Smith Professor of Chemistry and Biochemistry and senior author of the study at Notre Dame.

“The new molecules created by our research team are expected to be very useful for gold mining, as this alternative process can be used to offer milder conditions for both workers and the environment.”

This alternative mining method converts the gold containing ore into chloroacetic acid and extracts it using an industrial solvent. The molecules are capable of selectively separating gold from the solvent without the use of water (water stripping), which is economically and environmentally expensive.

“Our new molecules have the ability to eliminate this need for water removal and facilitate the recycling of solvents in this alternative extraction process,” said Smith.

In addition to their use for gold mining, these molecules could also be applied to “urban extraction”, which includes processes that remove valuable metals from streams containing urban waste water.