Key Salient Features for Gold Mining Applications

• Raw Material: Made from coconut shells, a renewable and sustainable resource.
• Micro porosity: High proportion of micropores (pores <2 nm), suitable for trapping small molecules like gases and volatile organic compounds.
• Hardness: High mechanical strength, meaning it does not easily break during handling or use.
• Low Ash Content: Less impurity, better efficiency in filtration and chemical reactions.
• Surface Area: Typically between 900–1200 m²/g, depending on the activation process. 

Production Process of Activated Carbon for Gold Mining Applications

• Carbonization: Coconut shells are heated in the absence of air to form char.
• Activation: Char is treated with steam or chemicals (e.g., phosphoric acid, potassium hydroxide) at high temperatures (600–900°C) to develop its porous structure.

Why Activated Carbon Works for Gold Adsorption

1.Highly Porous Structure:

• Activated carbon has an extremely high surface area (500–1500 m²/g).
• The internal pores provide sites for the gold-cyanide complex to adsorb.

2.Hydrophobic Interactions:

• Gold-cyanide complexes are slightly hydrophobic.
• Activated carbon is also hydrophobic, so the complexes are attracted to and retained on the carbon surface.

3.Van der Waals and Electrostatic Forces:

• Weak forces help hold the gold complexes on the carbon.
• In CIP/CIL systems, the carbon is kept in contact with the slurry for enough time for maximum adsorption.

4.Selective Affinity:

• Activated carbon shows a higher affinity for [Au(CN)_2]^− compared to many other metal cyanide complexes, making it selective and efficient for gold recovery.

What Happens After Adsorption.

1.Elution: 

• The gold is stripped from the carbon using a hot caustic solution.
• This produces a concentrated gold-bearing solution.

2.Electro winning or Precipitation: ·  

• Gold is recovered from the solution via electro winning or chemical precipitation.

3.Carbon Regeneration:

• The stripped carbon is thermally regenerated (often in a kiln) to remove any residual organics or contaminants, restoring its adsorption capacity.