Cyanide leaching has been the industry standard method for recovering gold from ore for decades, and SGS continues to remain at the forefront of this very successful gold recovery technology.
Carbon has been traditionally used to recover gold from cyanide leachates, but recent technological advances have resulted in the use of resins as a highly efficient and cost-effective method of gold recovery. SGS has the expertise to help you develop a gold flowsheet that optimizes gold extraction, gold recovery with reasonable operational costs and environmental sustainability.
SGS project managers can work with you to develop an effective flowsheet for your gold operation. Starting at the scoping or bench scale, we will design and demonstrate a testing program that will define and optimize the crucial gold recovery parameters including mineralogy, kinetics and chemical constraints.
Whether your final flowsheet uses carbon or resin technologies, the data gathered by SGS will enable you to make important operational decisions and provide capex and opex information for your feasibility study.
Carbon Technologies to Recover Gold
CIP (Carbon-in-pulp) / CIL (Carbon-in-leach) / CIC (Carbon-in-columns)
SGS metallurgists developed and continue to improve on these cost-effective, time-tested and proven processes. In each, activated carbon is used to extract gold from the cyanide leach solution. Such a carbon recovery system offers high recovery rates and lower capital and operating costs. These carbon recovery techniques include:
- Carbon-in-pulp
The ore is crushed, finely ground and mixed with the cyanide leach solution to form a slurry in an agitation tank. The activated carbon is introduced into the slurry and then removed by screening once it is fully loaded or “pregnant” with gold.
- Carbon-in-leach
This process is very similar to the CIP process. The main differences lie in the preparation of the slurry and method for removing the gold from the leachate. In a CIL process, the carbon is mixed with the leachate solution, not with pulp. This is a much less abrasive system meaning that the carbon lasts much longer than in a CIP process.
- Carbon-in-columns
During this process, the cyanide leaching solution passes through columns filled with ore. The process is highly effective for removing gold from low grade ore.
Resin Recovery Technologies
Resin RIL (Resin-in-leach)/RIP (Resin-in pulp)
In recent years, resin is replacing carbon as the gold recovery substrate of choice. SGS is the world leader in the development of this technology. The process used in resin recovery is similar to carbon, but the gold is adsorbed onto solid spherical polystyrene resin beads rather than activated carbon grains.
Resin recovery offers all the advantages of carbon recovery, with some additional benefits:
- Clear-cut mechanical and engineering advantages over carbon-in-column (CIC) recovery as a result of the flow characteristics of resin beads
- The size of the synthetic resin particles is more consistent than the natural carbon particles, allowing for easier control when adding adsorbant
- Better recovery rates are obtained from refractory ores or those containing high levels of clay or organic compounds
Contact SGS early in the planning stage of your gold project. Our robust technology and globally-recognized technical expertise can give you the information you need for an efficient and cost-effective gold flowsheet for your operations.