Gold and silver are extracted from their native ores by MacArthur-Forrest cyanide process.

Extraction of Gold using Cyanide Process
Gold is extracted from its ores using the cyanide process, which involves leaching gold from the ore with a cyanide solution. The cyanide process is widely used for extracting gold due to its efficiency and cost-effectiveness.

Leaching Process
- In the cyanide process, the ore is crushed and then mixed with a dilute cyanide solution.
- The cyanide solution reacts with the gold in the ore to form a gold-cyanide complex.
- This complex is then separated from the ore using various methods such as carbon adsorption or precipitation.

Recovery of Gold
- Once the gold-cyanide complex is separated from the ore, the gold can be recovered by various methods such as electrolysis or precipitation.
- The recovered gold is then further purified to obtain pure gold.

Advantages of Cyanide Process
- The cyanide process is highly efficient in extracting gold from low-grade ores.
- It is a cost-effective method compared to other gold extraction processes.
- The process can be easily scaled up for commercial gold extraction operations.

Environmental Concerns
- While the cyanide process is effective in extracting gold, it also poses environmental risks if not managed properly.
- The use of cyanide can lead to water pollution and harm aquatic life if not properly treated and disposed of.
- To mitigate these risks, strict regulations and guidelines are in place for the safe use of cyanide in gold extraction processes.