Researchers from the Curtin University in Perth, Australia, have improved their glycine leaching technology to enhance gold extraction process.

The glycine leaching technology has been improved by the researchers by significantly enhancing the leaching rates for gold ore using a low concentration of a strong oxidising agent, known as potassium permanganate.

Upon assessing various oxidants for the new alkaline glycine gold leach system, the research team observed the most successful results with potassium permanganate.

According to Curtin University Western Australia (WA) School of Mines: Minerals, Energy and Chemical Engineering professor Jacques Eksteen and Dr Elsayed Oraby, the addition of potassium permanganate to the process could address the problems associated with leaching gold with glycine (in the absence of cyanide).

These problems include the need for higher temperatures, glycine concentrations and oxygen addition levels.

Eksteen said: “Traditionally, leaching or separating gold and other precious metals from an ore deposit or e-waste materials requires the use of cyanide – a highly toxic chemical compound that is known to have detrimental effects to the environment and to the human body.

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

Eksteen noted that the research team added low concentrations of potassium permanganate to the alkaline glycine system that resulted in leaching of 85.1% of gold from the ore deposit (similar to the extraction by cyanidation) at ambient temperature and using a substance known as a benign reagent.

Oraby said: “Researchers at Curtin University have spent years developing a new leaching process and our work broadens 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.”

In order to commercialise the new process, the Curtin team is working with minerals industry partner, Mining and Process Solutions (MPS).