Application of coconut shell activated carbon in gold refining, process analysis of adsorption method!

In the process of gold mining and refining, coconut shell activated carbon gold mining has become an indispensable key material due to its excellent adsorption performance. JS Activated Carbon will deeply explore the unique role of activated carbon in the gold refining process and its importance in achieving efficient and environmentally friendly gold extraction.

Unique characteristics of coconut shell activated carbon

Coconut shell activated carbon has excellent adsorption capacity due to its porous structure and huge specific surface area. Its specific surface area is generally between 500 and 1400 square meters per gram, and some high-performance carbons can even reach 2500 square meters per gram. This special structure enables several cubic meters of coconut shell activated carbon to effectively adsorb tiny molecules and ions in the solution, especially gold cyanide ions, which is crucial for gold refining.

Specific process of gold extraction

1. Preparation and adsorption of activated carbon

The first step of gold extraction is to prepare activated carbon. Selected coconut shell activated carbon is placed in a special adsorption tower, and the gold cyanide ion solution after cyanidation of gold ore flows through the tower. In this process, the gold cyanide ions are firmly adsorbed by the activated carbon. As the adsorption process proceeds, the activated carbon gradually approaches saturation, and then it needs to be replaced with new activated carbon or subsequent treatment.

2. Reduction and separation

When the adsorption capacity of activated carbon reaches saturation, it is taken out of the adsorption tower and heated. At this time, an appropriate amount of reducing agent, such as lead oxide or borax, is added to promote the reduction of gold cyanide ions to metallic gold. The reduced gold particles are separated from the activated carbon, and impurities are removed by screening and washing to ensure the purity of the final product.

3. Refining and Purification

The separated gold particles need to be further refined and purified to remove any residues and finally obtain high-purity gold. This process usually involves high-temperature smelting and multiple screenings to ensure the purity of the gold.

Environmental protection measures and sustainable development

In the process of gold refining, environmental protection is always an important consideration. The use of activated carbon adsorption not only improves the recovery rate of gold, but also significantly reduces the use of chemical reagents and the discharge of wastewater. For used activated carbon, we take scientific recycling and treatment measures to avoid secondary pollution to the environment.

Process types for gold extraction by activated carbon adsorption

The processes for gold extraction by activated carbon adsorption mainly include carbon-in-slurry method (CIP method), carbon-in-leach method (CIL method) and carbon column method (CIC method). These process steps basically include the following links:

Adsorption: Use activated carbon to adsorb gold from cyanide slurry to produce gold-loaded carbon.

Desorption: Desorb the gold-loaded carbon, transfer the gold back into the solution, and produce gold-desorbed precious liquid.

Recovery: Use various methods to recover gold from gold-containing precious liquid.

Regeneration: Regenerate the desorbed lean carbon to restore its activity and return it to the adsorption operation for reuse.

Characteristics and adsorption process of activated carbon

Activated carbon can be divided into two categories: powdered carbon and granular carbon. Granular carbon can be made from a variety of carbon-containing materials. Studies have shown that the structure of activated carbon is similar to graphite, consisting of tiny chips with a thickness of only a few carbon atoms. The adsorption process of activated carbon mainly includes three steps: external diffusion, internal diffusion and adsorption.

Factors affecting activated carbon adsorption

The adsorption capacity of activated carbon is affected by many factors, including:

Activated carbon type: Coconut shell charcoal and apricot kernel charcoal have better adsorption characteristics than coal charcoal and coke charcoal.

Adsorption equipment structure: Common adsorption tanks are axial flow and radial flow. Axial flow tanks have low resistance and low wear rate.

Slurry properties: The particle size, concentration, viscosity and organic matter content of the slurry will affect the adsorption effect.

Carbon extraction equipment and process operation

At present, there are three main types of carbon extraction equipment: turbine pump, jet pump and air mixing chamber. The carbon extraction process usually starts from the first tank, and carbon is extracted in series in each tank, and carbon is added to the last tank. The number of carbon extractions should be reasonably arranged according to experiments and theoretical calculations to maintain consistency of operation.

Desorption of gold-loaded carbon

The desorption of gold-loaded carbon is a reversible process. The gold on the gold-loaded carbon can be effectively desorbed into the solution by using appropriate methods. Common desorption methods include:

Normal pressure heating desorption method: Desorption is carried out at a temperature of 85-95℃ using a mixed solution of 0.1% NaCN and 1.0% NaOH, which takes 28-70 hours.

Pressurized desorption method: desorption is carried out under the conditions of 150-170℃ and 0.3432Mpa. The cycle is short but the equipment cost is high.

Alcohol desorption method: desorption is carried out under normal pressure, but because alcohol is flammable, it needs to be carefully controlled.

American and British desorption method: treatment is carried out using a specific solution. The operation is relatively complicated, but the effect is significant.

Regeneration of de-gold carbon

After multiple adsorption and desorption, the activity of activated carbon will decrease. The activity can be restored by acid regeneration or thermal regeneration. Practice has shown that the activity can be restored to more than 85% after thermal regeneration, even exceeding the activity of new carbon.

Matters needing attention during regeneration

Removal of organic matter: During the regeneration process, organic matter in the carbon should be removed as much as possible to improve the regeneration effect.

Control the regeneration temperature: Ensure that the regeneration temperature is evenly distributed to improve the recovery efficiency of activity.

Pay attention to the pore structure of the carbon: the blockage of the pores will affect the recovery of activity and needs to be cleaned in advance.

The importance of coconut shell activated carbon:

Coconut shell activated carbon plays an important role in the gold refining process. Its high efficiency and environmental protection characteristics make it the preferred material in the industry. With the promotion of the concept of sustainable development, the diversified application of activated carbon will continue to expand and promote the green development of various industries. Through scientific and reasonable processes and technologies, we can protect the environment while maintaining efficient refining and achieve a win-win situation for economy and ecology.