The ConSep ACACIA Reactor is a patented, high efficiency leaching system, exclusively designed to handle the high-grade concentrates produced by Knelson Concentrators. The system is designed to maximize gold recovery from gravity concentrates and provide numerous process advantages over a conventional gold room. Here's how it works….
Transfer of Concentrate to the reactor.
Knelson Concentrator gravity concentrate generated over a 24-hour period is held in a storage vessel in the gold room for subsequent transfer to the ConSep ACACIA Reactor.
Pre-washing of the gold concentrate to remove ultra-fine solids (slimes)
To ensure the leach overflow solution does not carry suspended solids that interfere with the subsequent gold electrowinning, and that water and subsequently pregnant solution can be recovered by drainage, the concentrate solids are fluidized for est. 30 minutes.
Reaction vessel overflow solution containing fine solids est. at -30 microns is discharge back to the grinding section.
3. Mixing of the Leach Reagents
The leach solution is made up in the reaction vessel feed tank that is fitted with a side-mounted mixer. Potable water (3.2 m3) is added to the tank and NaOH, NaCN and LeachAid are added as solids in that order and mixed.
4. Leaching of the Concentrate
The leach solution is pumped from the reaction vessel feed tank via the distributor through the reaction vessel at a rate sufficient only to fluidize the concentrate. This ensures that no fine solids are carried over in the pregnant overflow.
The leach solution is circulated through the reaction vessel for about 16 hours.
5. Recovery of Pregnant Solution and Washing of the Residue
At termination of leaching, the reaction vessel overflow is sampled for assay, the flow is stopped and drainage of the solution through the distributor to the reaction vessel feed tank is commenced. After about 15 minutes, when the solids in the reaction vessel have settled, pregnant solution is also taken off to the reaction vessel feed tank via the decant. This reduces the pregnant solution recovery time.
The wash water is applied as a spray to the surface of the residue solids. The minimum quantity of wash applied is approximately equal to the voids in the residue, which are about 0.5 m3.
6. Transfer of Solution to Electrowinning
The gold bearing solution, which is now all located in the solution tank, is transferred to direct electrowinning where the gold is recovered as cathode
7. Discharge of the Leach Residue
The leached residue is fluidized and then discharged to the grinding section.
The very coarse grinding ball chips fail to fluidize and are retained on the distributor screen. The grinding ball chip is physically removed from the reaction vessel.
8. Electrowinning
The pregnant solution and recovered wash solution in the reaction vessel feed tank are mixed and pumped to the electrowinning cell feed tank where it is sampled and the volume of the solution is measured. The solution in the electrowinning cell feed tank is pumped to the EW cell at controlled flow rate. Solution is circulated on the cell for a specific period of time determined by the cell tail assay.
9. Disposal of Electrowinning Tail
The EW tail is transferred in total to the CIL circuit
Request Additional Information
Do you require additional information? Complete the online information request form and a Knelson representative will contact shortly.
Share Your Knelson Experience
"At Musselwhite we have two Knelsons, and recently we have just completed a study to optimize both Knelsons. The work is done with the Knelson group in Vancouver."
- Nuri Hmidi, Metallurgist - Placer Dome, Canada
...more > >
