What is the Difference Between CIL and CIP

CIP and CIL are both methods used in gold mining to extract gold from ore using a cyanide solution and activated carbon. CIP stands for carbon in pulp, while CIL stands for carbon in leach.

What is the difference between CIL and CIP? CIL is a single stage process whereas CIP is a two stage process. CIP first involves leaching with cyanide, then adding activated carbon to absorb the gold. In contrast, CIL adds activated carbon directly to the leaching tank, allowing leaching and gold absorption to happen simultaneously.

Key Areas Covered

1. What is CIL (Carbon in Leach)  
      – Definition, Features 
2. What is CIP (Carbon in Pulp)
      – Definition, Features 
3. Similarities Between CIL and CIP
      – Outline of Common Features
4. Difference Between CIL and CIP
      – Comparison of Key Differences
5. FAQ: CIL and CIP
      – Answers to Frequently Asked Questions

Key Terms

Carbon in Leach, Carbon in Pulp, CIL, CIP

Difference Between CIL and CIP - Comparison Summary

What is CIL

CLI, which stands for Carbon in Leach, is a gold mining process. Preparation, leaching and adsorption, gold loaded carbon separation, and gold recovery are the major steps involved in this process.

In the preparation step, gold ore is crushed and is ground to fine powder. In the leaching and adsorption step, the ground ore is mixed with a cyanide solution to form a slurry. The cyanide dissolves the gold particles, creating soluble gold-cyanide complexes. Activated carbon is also present in the slurry. The highly porous structure and large area of the carbon attracts the gold ions.

The next step is the gold-loaded carbon separation. The gold-laden carbon needs to be separated from the leftover ore pulp (the barren slurry). This separation might involve screens or filtration techniques. The final step is the gold recovery step.

The gold is then stripped from the loaded carbon through a process called elution. This often involves using a hot caustic solution that dissolves the gold off the carbon. Finally, the recovered gold solution goes through electrowinning or smelting to obtain pure gold.

Advantages of CIL include it being a one stage process and being a simple operation procedure compared to other methods.

What is CIP

CIP, which stands for carbon in pulp, is another gold mining method. There are a few steps in this process. First, the gold ore is crushed and ground into a fine slurry. To dissolve the gold particles, oxygen and sodium cyanide are introduced into it. This proceeds with the addition of activated carbon.


Then, gold-laden carbon is separated from the barren pulp. Through a process like electrowinning, the gold is recovered from the loaded carbon, leaving the carbon ready for reuse. Finally, the leftover pulp undergoes treatment to minimize environmental impact.

As CIP uses cyanide, which is a hazardous chemical, it is essential to dispose of the waste products properly.

Similarities Between CIL and CIP

  1. Both methods aim to extract gold from crushed ore using activated carbon.
  2. Activated carbon plays a central role in both processes.
  3. Both CIP and CIL utilize a cyanide solution (usually sodium cyanide) to dissolve gold particles in the crushed ore.
  4. Both processes require constant mixing and agitation in tanks.

Difference Between CIL and CIP


  • CIL (Carbon in Leach) is a gold extraction method where cyanide leaching and carbon adsorption take place simultaneously in a series of tanks. On the other hand, CIP (Carbon in Pulp) is a gold extraction method where cyanide leaching and carbon adsorption occur in the same tanks.


  • CIL requires a larger amount of carbon compared to CIP.

Carbon Concentration in the Slurry

  • Since CIL has more carbon in the tank, the overall carbon concentration in the slurry is lower than in CIP.

Gold Recovery Rate

  • CIL can achieve slightly higher gold recovery rates due to the continuous interaction between carbon and the leaching solution.


  • CIP is a simpler process that operates with less equipment involved.


CIL and CIP are gold mining techniques that use cyanide and activated carbon to extract gold. CIL is a one-stage process where leaching and adsorption happen simultaneously, while CIP separates these steps. This is the basic the difference between CIL and CIP.


1. What is the carbon-in-pulp method?

The carbon-in-pulp (CIP) method is a gold extraction technique. It uses activated carbon like a sponge to soak up gold dissolved in cyanide solution. The carbon-gold mixture is then separated, and the gold is recovered from the loaded carbon.

2. What is the role of carbon in extraction?

In extraction, carbon acts as a reducing agent, particularly for metals lower than it on the reactivity series.

3. What is carbon-in-leach?

Carbon-in-leach (CIL) is a gold extraction method where gold dissolves in cyanide solution and is simultaneously absorbed by activated carbon.

4. What is carbon sludge?

After use in water treatment or gold extraction, the spent carbon becomes carbon sludge, requiring disposal or potentially regeneration.

5. What is the difference between slurry and sludge?

Slurry and sludge are both mixtures, but slurry is thinner and flows more easily. Slurry has a higher liquid content and can be pumped, while sludge is thicker and needs special pumps.


1. “Carbon in Pulp” Wikipedia. Wikipedia Foundation. 

Image Courtesy:

1. “Carbon In Pulp (with text)(CC BY-SA 3.0) via Commons Wikimedia

About the Author: Hasini A

Hasini is a graduate of Applied Science with a strong background in forestry, environmental science, chemistry, and management science. She is an amateur photographer with a keen interest in exploring the wonders of nature and science.

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