Kinetics and deposit morphology of gold cemented on magnesium, aluminum, zinc, iron and copper from ammonium thiosulfate–ammonia solutions

The kinetics of gold cementation by magnesium aluminum, zinc, iron and copper at equal conditions as well as the morphology of cementation products and the dissolution of cementing agents were investigated. Both the effect of cementing agents on gold cementation rate and the dissolution of metals decrease in order Cu > Zn > Mg > Fe > Al. High dissolution of magnesium, zinc, iron and copper per mol deposited gold was found. Zinc is the most efficient cementing agent. Magnesium and iron can be used in gold cementation practice but the extremely slow cementation rate prevents the practical application of aluminum.Significant differences in the morphology of gold deposits on magnesium, aluminum, zinc, iron and copper were found: thick deposit layers with small or large cracks were observed on magnesium or zinc; porous layers of fern leaf-shaped dendrites on copper; compact smooth deposit of fine crystallites on iron and small very rare formations of fine dendrites on aluminum.