2021-07-05

Why is there a gold mine? Scientists have found the answer

By yqqlm yqqlm

Why is there a gold mine? Scientists have found the answer

For thousands of years, gold has been due to its purity and stability Sex is cherished. It is also scarce enough to maintain its value-the World Gold Council estimates that all the gold ever mined in the world is small enough to fit into a 20x20x20 meter cube. It is valued for its beauty, but also because it is one of the most inert metals in the entire periodic table, and it does not easily react with other substances. So why should gold be gathered in sufficient quantities for mining, and why are there gold deposits?

Some gold is discovered in the form of gold nuggets, which is the dream of prospectors, but a considerable amount of gold is combined with minerals. As we all know, gold is related to minerals containing iron and arsenic, such as pyrite and arsenopyrite. These minerals act a bit like sponges, concentrating gold, one million times more than gold found elsewhere in nature, such as in hot spring water that transports gold. The gold is chemically combined in these minerals, so it is invisible to the naked eye.

Why is there a gold mine? Scientists have found the answer(1)

A giant gold mine in Western Australia (Super pit). Pyrite and arsenopyrite are the main ore minerals, which concentrate invisible gold and arsenic.

The scientific team used the intense X-ray beam produced by the European Synchrotron Accelerator (ESRF) in Grenoble, France, to study the role of enriched gold minerals, which can detect the chemical bonds between minerals and gold.

They found that when the mineral is rich in arsenic, gold can enter the mineral structure site by directly combining with arsenic (chemically speaking, forming Au(2+) and As(1-) bonds) , Which makes gold stable in minerals. However, when the arsenic concentration is low, gold does not enter the mineral structure, but only forms a weak gold-sulfur bond with the mineral surface.

The lead researcher, Dr. Gleb Pokrovski, CNRS, GET-CNRS-Toulouse Paul Sabbatir University Research Director said: “Our research results show that arsenic promotes the concentration of gold. This arsenic drive The gold pump explains how these iron sulfides can capture and release gold on a large scale, thereby controlling the formation and distribution of deposits. From a practical point of view, this means that it will be easier to find new sources of gold and other precious metals because they Combined with arsenic-containing iron sulfide. It may also open the door to control chemical reactions. If we can improve gold processing, we can recover more gold.”

The new model just determines why gold tends to be found together with arsenic. Dr. Pokrovski continued: “For centuries, people have known that gold was discovered together with arsenic, which caused serious health problems for gold miners. Now that we know what is happening at the atomic level, we can start to see Is there any way to prevent this situation”.

The harmful link between arsenic and gold is well known in France and other parts of the world, including the Salsigne mine near Carcassonne. This is one of the largest gold mines in Western Europe and was once the largest arsenic producer in the world. It was closed in 2004, but the environmental consequences of arsenic pollution still exist in the area.

Dr. Jeffrey Hedenquist of the University of Ottawa commented: “Geologists and prospectors have long known that gold may be related to arsenic-rich minerals. In the past few decades, others have quantified this A connection. The findings of Dr. Pokrovski and his team now help explain why we see this connection. It is caused by the atomic-level attraction between gold and arsenic. This marriage is arranged by the structure of certain minerals. .”