There are predominantly three methods employed in industry to adsorb leach gold from a pulp stream onto activated carbon. The methods are Carbon-in-Leach (CIL), Carbon-in-Pulp (CIP) and Pumpcell technology. CIL and CIP are typically counter current operations while the Pumpcell technology makes use of the carousel mode of operation.
The CIL mode of operation is when the leach and adsorption circuit are combined into a single process. A CIL mode of operation has advantages when carbon enhances the leach efficiency by competing with other gold adsorbants (pre robbers) constituents in the ore.
In a CIP operation the majority of the leachable gold has been leached prior to the first carbon adsorption stage. The gold adsorption is carried out in specifically designed tanks that are situated after the leaching tanks in the overall process flow. The adsorption tanks are typically a quarter to a tenth of the size of the leach tanks.
The CIL and CIP modes of operations occur in a number of tanks placed in series. Pulp flows continuously from the first tank to the last, while carbon is pumped counter current from the last tank to the first. The main difference between CIL and CIP lies in the extent to which gold is leached prior to carbon adsorption.
For both CIL and CIP applications the adsorption tanks can be arranged in the conventional cascading configuration or the tanks can be positioned on the same horizontal elevation.
Pumpcell technology was developed to introduce an alternative approach to the design of conventional CIP adsorption circuits. Pumpcell technology has become the carbon adsorption route employed on modern day gold plants. The operating cost benefit realised over life of mine have attributed to the increasing popularity of the Pumpcell technology.
For more information about equipment specific to CIL and CIP applications click below.