Treatment process of gold-bearing tailings

Gold-bearing tailings are the residual materials that remain after the extraction of gold from ore. They contain various amounts of gold and other valuable minerals, as well as harmful substances such as heavy metals and cyanide. The treatment process of gold-bearing tailings aims to recover the gold and other valuable minerals while minimizing the impact of harmful substances on the environment.

The following are the common treatment processes and methods for gold-bearing tailings:

1. Gravity separation: This process separates the heavy minerals from the lighter ones using the force of gravity. It is often used in the initial stage of gold-bearing tailings treatment to recover the coarse gold and other heavy minerals.

2. Flotation: Flotation is a process that uses chemicals and air to separate the valuable minerals from the unwanted materials. It is effective for separating the fine-grained gold and other minerals from the tailings.

3. Cyanide leaching: Cyanide leaching is a widely used process for extracting gold from the tailings. The tailings are mixed with a solution of sodium cyanide and water, which dissolves the gold and other precious metals. The gold is then recovered from the solution by adsorption onto activated carbon or by precipitation with zinc powder.

4. Carbon-in-pulp (CIP): CIP is a method of gold recovery that involves adsorption onto activated carbon. The gold-containing solution is passed through a series of tanks containing activated carbon, which adsorbs the gold. The loaded carbon is then stripped of the gold using a caustic solution, and the gold is recovered by electrowinning or precipitation.

5. Heap leaching: Heap leaching is a process that involves stacking the tailings into a heap and irrigating them with a solution of sodium cyanide and water. The solution percolates through the heap, dissolving the gold and other precious metals. The pregnant solution is then collected and the gold is recovered by adsorption onto activated carbon or by precipitation with zinc powder.

6. Biological treatment: Biological treatment involves using microorganisms to remove or degrade harmful substances in the tailings. For example, bacteria can be used to oxidize and remove cyanide from the tailings. This process can be used in conjunction with other treatment methods to reduce the environmental impact of the tailings.

In conclusion, the treatment process of gold-bearing tailings involves a combination of physical, chemical, and biological methods to recover the valuable minerals and reduce the impact of harmful substances on the environment. The choice of treatment method depends on the characteristics of the tailings and the desired outcomes of the treatment process.