Gold recovery is a key process in the modern mining industry, as the efficiency of recovery of each gram of gold has a direct impact on a company's profitability.
As gold prices continue to rise, mining companies are placing increasing emphasis on improving the efficiency and effectiveness of their gold recovery processes. Activated carbon has become an indispensable material in the modern gold recovery process due to its excellent adsorption capacity and selectivity.
This article will detail the role and benefits of the activated carbon in gold recovery and how to choose the right activated carbon to optimize the gold extraction process.
What is activated carbon and what role does it play in gold recovery?
Activated carbon is a material with a highly porous structure which, due to its large specific surface area and developed pore structure, has an extremely high adsorption capacity.
In gold mining, activated carbon is mainly used in the cyanide adsorption process, i.e. it is used to recover the gold dissolved in a cyanide solution. This process is crucial in modern gold recovery methods, especially in the CIL (carbon-in-leach) and CIP (carbon-in-pulp process) processes, which are widely used in the industry.
Main advantages of activated carbon
- High adsorption capacityDue to its large specific surface area and porous structure, activated carbon can effectively adsorb gold cyanide complexes, thus improving the gold recovery rate.
- High mechanical strengthActivated carbon has a high hardness and wear resistance, which allows it to withstand the complex hydrodynamic conditions of the gold recovery process and reduce losses.
- Ease of desorptionGold-cyanide complexes can be easily desorbed from the activated carbon, which facilitates gold recovery.
Gold recovery process with the use of activated carbon
In the gold recovery industry, the application of activated carbon is mainly focused on the extraction of dissolved gold ions from cyanide-containing solutions, particularly in the CIL (Carbon in Leach) and CIP (Carbon in Pulp) processes. The key steps of activated carbon in the gold recovery process are listed below:
Leaching
Leaching is the starting point of the activated carbon gold recovery process. The ore, after being crushed and ground, is processed into fine particles to increase the contact area with the solution.
Subsequently, the ore is mixed with a cyanide solution, dissolving the gold and forming soluble gold cyanide complexes ([Au(CN)₂]-). This process is generally carried out in agitation tanks or heap leach tanks.
Adsorption
Adsorption is the central step of the process. In this stage, activated carbon is added to the solution containing gold cyanide complexes, and, through its large specific surface area and porous structure, the gold is adsorbed on the surface of the activated carbon particles.
Desorption
During adsorption, the gold is fixed on the surface of the activated carbon. To remove the gold from the activated carbon, the desorption process must be performed. This process is usually carried out using a high temperature and pressure desorption method, where a desorbing agent (such as a cyanide and sodium solution) is introduced, which separates the gold from the carbon particles and brings it back into solution.
Coal regeneration
After desorption, the activated carbon loses part of its adsorption capacity, so it is necessary to regenerate it to restore its effectiveness. Regeneration is generally performed by a thermal process, where organic impurities on the surface of the carbon are burned off, reactivating its porous structure.
Electrolysis for gold extraction
The desorbed solution, which contains high concentrations of gold cyanide complexes, then undergoes an electrolysis process to extract the gold from solution. This process is typically performed in an electrolytic cell, where the anode is made of insoluble material and the cathode is made of stainless steel or other metallic material.
Request a QuoteHow to select the right activated carbon for gold recovery
The selection of the right activated carbon for gold recovery is crucial to improve the efficiency of the process. Some key factors to consider are listed below:
- Particle sizeThe particle size of activated carbon influences its adsorption capacity. A suitable particle size can increase the contact efficiency between the activated carbon and the gold solution, improving the gold adsorption rate.
- Adsorption capacityThe adsorption capacity of activated carbon depends on its specific surface area and internal pore structure. The higher the adsorption capacity, the higher the recovery rate.
- Mechanical resistanceHigh quality activated carbon must have sufficient wear resistance to withstand several regeneration cycles without disintegrating.
- PurityIt is essential to choose activated carbon without impurities to avoid interference in the gold recovery process or contamination of the solution.
For gold recovery, we recommend the use of coconut shell activated carbonspecifically designed for CIL and CIP processes. This type of activated carbon offers excellent adsorption performance, high strength and long life, being the ideal choice to optimize the gold recovery process. Detailed parameters are presented below:
| Indicator | Parameter |
|---|---|
| Raw materials | Coconut shells |
| Size | 6-12 meshes, 8-16 meshes |
| Iodine value | 950-1200 mg/g |
| Ashes | <3% |
| Hardness | ≥98% |
| CTC | 55-60% |
Conclusion
Activated carbon plays a crucial role in the gold recovery process, as it not only improves the recovery rate, but also significantly reduces costs and minimizes environmental impact. By selecting the right activated carbon and optimizing each stage of the process, mining companies can achieve higher profits and sustainable development.
PuroCarbon S.L. is dedicated to providing high quality activated carbon products to customers worldwide. If you would like to learn more about our products or request a customized quote, please do not hesitate to contact us. contact with us. We are here to help you achieve greater success in your mining operations.