Gold Extraction And Recovery Process

Gold extraction and recovery processes refer to the methods used to separate gold from its ores. There are various techniques used in the extraction and recovery of gold, including:

Gravity concentration: This is the separation of gold particles based on the difference in their specific gravity. It is used to recover coarse gold particles and is usually the first step in the gold recovery process.

Flotation: This is the separation of gold particles from other minerals using air bubbles. It is used to recover finer gold particles that cannot be recovered by gravity concentration.

Cyanidation: This is the most commonly used method for gold extraction. It involves the use of a weak cyanide solution to dissolve gold from its ore. The gold is then recovered from the solution by adsorption onto activated carbon or by precipitation with zinc dust.

Carbon-in-Pulp (CIP): This is a variation of cyanidation that involves the use of activated carbon to adsorb gold from the cyanide solution. The carbon is then removed from the solution and the gold is stripped from the carbon using a hot caustic solution.

Merrill-Crowe process: This involves the precipitation of gold from the cyanide solution using zinc dust. The gold-zinc precipitate is then filtered, dried, and smelted to produce gold bullion.

Electrowinning: This is the recovery of gold from the pregnant leach solution by passing an electric current through the solution. The gold is deposited onto a cathode and then stripped from the cathode to produce gold bullion.

Heap leaching: This is the extraction of gold from low-grade ores or tailings by stacking the ore in a heap and then applying a dilute cyanide solution to the heap. The gold is then recovered from the solution using the carbon-in-pulp or Merrill-Crowe process.

Each of these techniques has its advantages and disadvantages, and the choice of technique will depend on various factors such as the type of ore, the grade of the ore, the size of the gold particles, and the economics of the process.