Two Cyanidation Routes, One Goal
CIL and CIP are both cyanidation processes that dissolve gold from finely ground ore and adsorb it onto activated carbon. Gold recovery on suitable ores can reach 99%. The difference is in how leaching and adsorption are arranged.
Carbon-in-Pulp (CIP)
In a CIP circuit, cyanide leaching happens first in dedicated tanks. The gold dissolves into solution before the slurry moves to a separate train of carbon tanks, where the dissolved gold is adsorbed onto activated carbon.
CIP is often preferred where the ore leaches quickly, because leaching is not slowed down by carbon moving through the same tanks.
Carbon-in-Leach (CIL)
In a CIL circuit, leaching and carbon adsorption happen together in the same tanks. Carbon is added to the leaching tanks themselves, so gold is adsorbed as it dissolves.
CIL is a good fit where gold is slow to leach, because continuous adsorption keeps the gold concentration in solution low, which can drive the reaction forward more effectively.
How to Choose
The choice between CIL and CIP depends on your ore's leaching kinetics, which are measured in the laboratory before design. Key factors include:
- Leaching speed — slow leach often favours CIL; fast leach may suit CIP.
- Carbon handling — the two circuits differ in how much carbon is carried through the tanks.
- Ore grade and throughput — larger plants are engineered around the same decision, using larger tanks.
Both routes use the same downstream equipment: elution to strip gold from carbon, electrowinning to recover it, and smelting to produce doré.
Equipment Xinhai Supplies
Xinhai designs and supplies complete CIL/CIP plants, including:
- Dual-impeller leaching and agitation tanks up to 20 m × 20 m
- Carbon handling, screening and regeneration circuits
- Elution systems from 200 kg to 3,000 kg
- Electrowinning cells and gold room design