Activated carbons for gold recovery sector - Manufacturing, Other
Activated carbon has long been used as an adsorbent in the gold processing industry to recover gold from mining operations. Due to its high surface area and exceptional hardness, coconut shell GAC (granulated activated carbon) is the main product used in carbon-in-leach (CIL), carbon-in-pulp (CIP), and carbon-in-column (CIC) operating systems.
Gold Recovery Process
For gold recovery, water and a cyanide such as calcium cyanide, sodium cyanide, or potassium cyanide, are added to ore or scraps to form a slurry.
The gold will leach out and mix with the cyanide into a solution. Activated carbon is then used to separate and store the gold, which is removed as the final step of the process.
There are three basic operating systems in use for modern gold recovery:
Carbon in Pulp:Carbon in pulp, or CIP, processing occurs when the leaching takes place in an agitation tank before the activated carbon is introduced.
Carbon in Leach:Carbon in leach, or CIL, occurs when the activated carbon is added to the slurry before any leaching occurs. The gold is both leached and adsorbed simultaneously.
Carbon in Column:Carbon in column, or CIC, is a completely different process. After leaching, the gold-cyanide solution is poured into massive columns packed with activated carbon.
There are specific pros and cons to each operating system, but all ultimately serve the same purpose of gold recovery.
Why Use Activated Carbon?
Activated carbon has a remarkable capacity for adsorption. The activation process gives it a submicroscopic porous network and a tremendous surface area, providing numerous bonding points for gold molecules. These molecules are attracted by the surface molecules of the activated carbon, allowing them to activated carbon for later desorption.
What Happens to the Used Activated Carbon?
After the gold recovery process is finished, the activated carbon is considered “spent.” However, allowing it to be used again. Some recovery operations are capable of reactivating their own carbon, but many prefer to send spent carbon to a specialist for reactivation.