Their research shows that a unique “dense liquid layer” at the interface between pyrite and water acts as a “nanofactory,” according to a research article published in the journal PNAS on Thursday .
This layer promotes the nucleation, growth, and enrichment of gold, even in fluids with very low gold concentrations, for example 10 parts per billion .
This finding provides a new perspective in understanding the formation of gold ore from aqueous solutions containing gold.
Pyrite-induced gold precipitation is a crucial step in the formation of high-grade gold deposits, but the interfacial dynamic mechanism remains unclear.
Previous studies have mostly relied on post-reaction analysis, making it difficult to capture the instantaneous gold precipitation process.
In this latest research effort, a collaborative team led by the Guangzhou Institute of Geochemistry of the Chinese Academy of Sciences (CAS), successfully observed the reaction between pyrite and a low-concentration gold solution in real time .
The results showed that approximately 13 minutes after contact, a "dense liquid layer" formed around the pyrite. Approximately 20 minutes later, gold nanoparticles began to appear within this layer, with their number and size gradually increasing over time.
These observations provide important evidence for understanding how gold forms at the pyrite-water interface.
Moreover, this finding also refutes the traditional view that “gold mainly originates from deep hydrothermal fluids,” and opens new avenues for explaining nanoparticle-induced mineralization processes in nature.
