The advantages of using coconut shell for active recovery of gold: low cost, simple operation, suitable for large-scale processing of low-grade ores. High recovery rate (up to 90% or more). Here are the main application methods and steps of activated carbon in gold extraction:
1. Carbon-in-Pulp Method (CIP)
Applicable scenarios: used for processing the pulp after cyanide leaching (gold exists in the form of cyanide gold complexes in the pulp).
Process:
Cyanide leaching: After crushing the ore, it is mixed with sodium cyanide (NaCN) solution, and gold dissolves to form [Au(CN)₂]⁻.
Adsorbing gold: Activated carbon (granular, usually coconut shell carbon) is added to the pulp. The activated carbon selectively adsorbs the gold cyanide complexes.
Separating carbon from pulp: The gold-loaded carbon and tailings are separated through sieving.
Desorption and electrolysis: The gold-loaded carbon is desorbed using a high-temperature alkaline sodium cyanide solution or alcohol-alkaline solution, and then obtained through electrolysis as pure gold.

2. Carbon In Leach (CIL) Method
Difference from CIP: Cyanide leaching and activated carbon adsorption are carried out simultaneously, shortening the processing time.
Advantages: Reduces the loss of gold during the leaching stage and is suitable for ores containing interfering substances (such as organic carbon).
3. Carbon Column Adsorption in Heap Leaching Method
Applicable scenarios: Heap leaching of low-grade gold ores.
Process:
Cyanide solution is sprayed onto the ore heap, dissolving gold and forming a gold-containing solution.
The solution passes through an adsorption column filled with activated carbon, where gold is adsorbed by the carbon.
The gold-loaded carbon is desorbed for further purification.

Key features of activated carbon：

High specific surface area: 500–1500 m²/g, providing sufficient adsorption sites.

Selective adsorption: preferentially adsorbs [Au(CN)₂]⁻ rather than other metal ions.

Mechanical strength: wear-resistant, suitable for slurry environment.

Regeneration ability: can be reused after high-temperature activation.

Activated carbon adsorption is still one of the mainstream processes for gold smelting due to its high efficiency and economy, especially when treating low-concentration gold solutions. In practical applications, CIP, CIL or heap leaching combined processes should be selected according to the characteristics of the ore.