Researchers find cyanide-free gold leaching process

Researchers at Curtin University in Western Australia have come up with a leaching process for gold extraction that does not use cyanide.
Researchers find cyanide-free gold leaching process Researchers find cyanide-free gold leaching process Researchers find cyanide-free gold leaching process Researchers find cyanide-free gold leaching process Researchers find cyanide-free gold leaching process

Staff reporter

Staff reporter

As part of an eight-year study Curtin University researchers developed an improved glycine leaching technology that enhances the leaching rates for gold ore without using cyanide, a highly toxic chemical compound known to have detrimental effects on the environment and the human body.

Typically when leaching gold with glycine without cyanide miners need higher temperatures, glycine concentrations and oxygen addition levels.

The Curtin process requires none of these.

Co-research lead and chair for extractive metallurgy for the Future Battery Industries Cooperative Research Centre Jacques Eksteen said the technology used a low concentration of the strong oxidising agent potassium permanganate, which produced better results compared with other oxidants for the alkaline glycine gold leach system.

"Traditionally, leaching or separating gold and other precious metals from an ore deposit or e-waste materials requires the use of cyanide," Eksteen said.

"Industrially, it is very expensive to detoxify cyanide, but it still does not eliminate the risks associated with transporting, handling and processing the chemical."

When low concentrations of potassium permanganate were added to the glycine system, the researchers were able to leach 85.1% of gold from the ore deposit at ambient temperature.

Co-research lead and senior research fellow Elsayed Oraby said researchers at Curtin University had spent years developing a leaching process and their work broadened the use of this patented technology, making it more suitable for extracting gold deposits.

"We believe this new process will bring many benefits to gold extraction industries, which from an environmental point of view, is a much friendlier extraction method," he said.