Producing Gold (Au)

Au: Gold

This element is known from ancient ages.

Abundance: 0.08ppm(in the earth's crust)

Put powder of gold ore into solution of sodium cyanide in air.

4Au + O2 + 8CN(-) + 2H2O 4Au(CN)2(-) + 4OH(-)

Add powder of zinc in the solution.

2[Au(CN)2](-) + Zn [Zn(CN)4](2-) + 2Au

Add deposits and gold into hot concentrated sulfuric acid, and dissolve silver.

2Ag + SO4(2-) + 4H(+) 2Ag(+) + SO2 + 2H2O

Gold deposits. Silver is recovered from remained solution.