What does cyanide leaching involve in the extraction of gold?

Cyanide leaching involves a chemical process where cyanide is used to dissolve and separate gold from its ore. This method is particularly effective for extracting gold from low-grade ores, as it allows for the recovery of gold that would otherwise be too expensive to extract using traditional methods. In this process, crushed ore is treated with a cyanide solution, which selectively reacts with gold, forming a soluble gold cyanide complex. This complex is then separated from the ore, allowing for the recovery of gold by further chemical processes, such as precipitation or absorption onto activated carbon.

This technique is notable for its efficiency and effectiveness in mining operations, especially as new innovations improve its sustainability and safety, mitigating environmental concerns associated with cyanide use. Other options addressed different aspects of gold processing but do not accurately describe the cyanide leaching method. For instance, crushing ore is a preparatory step for various extraction methods, while electrolytic refining refers to purifying already extracted gold, making those processes distinct from cyanide leaching. Similarly, heat separation is associated with traditional smelting techniques, which differ fundamentally from the chemical dissolution approach that cyanide leaching employs.