A large proportion of the world’s silver is produced as silver flotation concentrate and is sold to smelters for treatment. This incurs costs in smelter charges, transport and often extra taxes. The ILR has the ability to add value by treating silver flotation concentrates to recover silver metal on site. The intensive leaching conditions of high NaCN in solution and high dissolved oxygen levels overcome the issue with silver’s slow dissolution rate in traditional CIL-CIP circuits and the scrubbing action of the rolling drum reduces the formation and impact of insoluble silver sulphide minerals on the surface of the silver.
Silver leaching chemistry is complex due to the many silver minerals involved. This often requires a finer grind, higher cyanide conditions and longer residence times than what is required for gold and makes test work essential. Gekko have experience in optimising the leaching of silver concentrates through implementing successful projects such as Hochschilds Ares and San Jose concentrate treatment plants.
Due to increasing demand for the treatment of higher masses of silver flotation concentrates Gekko is currently developing the ILR45000 which will increase treatment rates by an order of magnitude – minimum of half a tonne an hour up to a nominal ten tonnes per hour depending on leach residence.