ClipArt ETC
In the gold extraction process, finely crushed ores are leached in vats with a very diluted solution of Potassuim Cyanide (KCN), containing 0.05 to 0.3 percent KCN (or its equivalent, Sodium Cyanide, NaCN) which is allowed to remain for twelve to twenty-four hours to dissolve the gold.

Cyanide Leaching Tank (Gold Extraction)

In the gold extraction process, finely crushed ores are leached in vats with a very diluted solution…

This furnace is used to purify a gold concentrate. The gold concentrates, if non-pyritic, are treated in grinding pans in the bottom of which mercury is placed. The amalgam (mercury alloy), after squeezing out the excess mercury, is heated in the retort, to distil (separate) off the rest and leave the gold, which is then melted and cast into bars of gold bullion of varying fineness.

Retort Furnace for Gold Bullion

This furnace is used to purify a gold concentrate. The gold concentrates, if non-pyritic, are treated…