Reduction Potential Gold

gold reduction potential — Figure 2 and 3 Au–H2O and Au–CN–H2O diagrams at 25°C | **Reduction Potential Gold**

The oxidation-reduction (dissolution and precipitation) of gold from Au –> Au+ +e- is driven by this equation. Without using a gold periodic table or a oxidation potential chart, you can simply review the chemistry here:

Figure 1 is Au–H2O system: No stability region for gold ions between lines; can’t dissolve Au in aqueous solutions (for now)
Figure 2 shows why we can’t dissolve gold; Figure 3 shows how we can (This is why cyanide is used).

Vertical line at bottom for H+ + CN– = HCN (g); impacts other lines.
Curvature of lines; reflects changing activity coefficients

These are controlled by water salinity as they need a strong oxidizing environment.

The redox potential of this system VS pH is shown in Figure 1

Learn all about oxidation and reduction:

Witness the magic of gold oxidation:

View the metallurgy gold reduction process:

David
September 18, 2015
3:19 am