【Recovery Gold】Cyanidation treatment method of complex gold ore

Cyanidation is a commonly used process for the extraction of gold from ores and concentrates. However, some gold ores and concentrates can be considered "complex" due to the presence of various minerals, such as sulfides and refractory ores, which can make the cyanidation process more challenging. In this case, additional steps may be required to effectively recover gold.

Here are some approaches to cyanidation of complex gold ores and concentrates:

Pre-treatment

Pre-treatment is a process that involves the treatment of the ore or concentrate before cyanidation. The purpose of pre-treatment is to increase the accessibility of gold by removing interfering minerals or modifying the ore structure.

Roasting: Roasting is a common pre-treatment method for refractory gold ores, which contain minerals that resist cyanide leaching. Roasting involves heating the ore in the presence of air or oxygen to convert sulfides to oxides, which are more amenable to cyanide leaching.

Bioleaching: Bioleaching is a process that uses microorganisms to oxidize sulfide minerals and release gold. The microorganisms are added to the ore or concentrate and allowed to grow and produce acid, which then oxidizes the sulfides.

Pressure oxidation: Pressure oxidation involves the treatment of sulfide ores or concentrates under high pressure and temperature, which oxidizes the sulfides and makes the gold more accessible to cyanide leaching.

Cyanide leaching

After pre-treatment, the ore or concentrate is subjected to cyanide leaching to dissolve the gold.

Heap leaching: Heap leaching is a process that involves the stacking of ore or concentrate on a pad and then applying a cyanide solution to the heap. The solution percolates through the heap, dissolving the gold, and the pregnant solution is collected and processed to recover the gold.

Tank leaching: Tank leaching is a process that involves the mixing of ore or concentrate with a cyanide solution in a tank. The slurry is agitated to ensure good mixing and contact between the cyanide solution and the gold. The pregnant solution is then processed to recover the gold.

Carbon adsorption

Carbon adsorption is a process that involves the adsorption of gold from the cyanide solution onto activated carbon.

Carbon-in-pulp (CIP): In CIP, the slurry is mixed with activated carbon, and the gold is adsorbed onto the carbon particles. The loaded carbon is then separated from the slurry and sent to an elution circuit to recover the gold.

Carbon-in-leach (CIL): In CIL, the slurry is first subjected to cyanide leaching, and then the pregnant solution is mixed with activated carbon to adsorb the gold. The loaded carbon is then separated from the slurry and sent to an elution circuit to recover the gold.

In summary, cyanidation of complex gold ores and concentrates can be challenging due to the presence of interfering minerals. Pre-treatment methods, such as roasting, bioleaching, and pressure oxidation, can be used to increase the accessibility of gold. Cyanide leaching can then be used to dissolve the gold, and carbon adsorption can be used to recover the gold from the pregnant solution. The choice of process depends on the characteristics of the ore or concentrate and the desired product specifications.