Coconut shell activated carbon in gold refining, due to its well-developed microporous structure, high specific surface area, and excellent mechanical strength, has become an indispensable key material in the adsorption-based gold extraction process. Its main application process and characteristics are as follows:
Core Application Process in Gold Refining
Adsorption Stage: Capturing Gold Ions
Coconut shell activated carbon (usually 0.4-3mm granules) is loaded into a specially designed adsorption tower (such as carbon-in-pulp (CIP), carbon-in-liquid (CIL), or carbon-column (CIC) process).
The slurry or solution containing gold cyanide ions (Au(CN)₂⁻) flows through the tower.
With its huge specific surface area and unique pore structure, coconut shell activated carbon efficiently adsorbs gold cyanide complexes from the solution onto its surface and into its pores through physical adsorption and partial chemical action, forming "gold-loaded carbon."
Desorption Stage: Releasing Gold
When the activated carbon is nearly saturated with adsorption, it is removed from the adsorption system.
Gold adsorbed on activated carbon is redissolved into the solution through desorption processes (such as atmospheric pressure heated desorption, pressure desorption, or alcohol desorption), forming a high-concentration "gold-containing precious solution."
Commonly used desorption solutions include a mixture of sodium cyanide (NaCN) and sodium hydroxide (NaOH).
Recovery and Regeneration Stage: Recycling
Gold Recovery: Gold is extracted from the gold-containing precious solution using traditional methods such as zinc powder replacement and electrolytic deposition, precipitating or separating it in solid form. This precipitated gold is then refined through smelting to obtain the finished product.
Activated Carbon Regeneration: The desorbed "lean carbon" can be treated by thermal regeneration (burning off adsorbed organic matter at high temperatures) or acidic regeneration to restore its adsorption activity. Regenerated activated carbon can recover more than 85% of its activity, enabling recycling and reducing operating costs.
