Scientists uncover the reason behind the detectability of gold

In a groundbreaking study, an international team of geochemists has uncovered the intricate relationship between gold and arsenic, shedding light on the formation of gold deposits and potentially paving the way for improved gold processing methods.

The research, conducted using the intense X-rays beam produced by the European Synchrotron (ESRF) at Grenoble in France, has revealed that certain minerals can concentrate gold up to a million times more than is found elsewhere in nature. This discovery could open the door to controlling chemical reactions, potentially improving gold processing and recovering more gold.

The study found that when the arsenic concentration is low, gold doesn't enter the mineral structure but only forms weak gold-sulfur bonds with the mineral surface. However, when the mineral is enriched with arsenic, gold can enter the mineral structural sites by directly binding to arsenic, allowing gold to be stabilized in the mineral. This link between arsenic and gold has been known for centuries, but the new research provides a more detailed understanding of the association.

Dr. Jeffrey Hedenquist, a geochemist from the University of Ottawa, has commented on the association between gold and arsenic-rich minerals. According to Dr. Hedenquist, this association is caused by an atomic-scale attraction between gold and arsenic.

Gold deposits are formed due to the presence of arsenic, as discovered by the research team. Gold is concentrated alongside arsenic, particularly in iron- and arsenic-containing minerals such as pyrite and arsenopyrite. The structure of these minerals plays a role in the association between gold and arsenic.

The findings of Dr. Pokrovski and his team help to further explain this association. They explain how iron sulfides can massively capture and then release gold, controlling ore deposit formation and distribution. This research could make it easier to find new sources of gold and other precious metals that bind to arsenic-containing iron sulfides.

The Salsigne mine near Carcassonne, France, was one of the largest gold mines and the world's largest arsenic producer at one time. The mine closed in 2004, but the environmental consequences of the arsenic pollution still persist in the region. Gold is often found with arsenic, causing health problems for miners.

Dr. Hedenquist's comments help explain why gold is often associated with arsenic-rich minerals. The new research provides valuable insights into the geological conditions and fluid chemistry that allow gold to precipitate alongside arsenic minerals, which is relevant for gold deposit formation.

This research not only deepens our understanding of the geology of gold deposits but also opens up possibilities for improving gold processing and recovery methods. As Dr. Pokrovski and his team continue to explore this fascinating association, we can look forward to further advancements in the field.