Manufacturer of Activated Carbon for Gold Recovery
Global Adsorbents is a leading Coconut Shell Manufacturer for
- Carbon in Pulp (CIP)
- Carbon-in-Leach (CIL)
- and Carbon-in-Column (CIC)
The MANTRA of success in mining gold lies in maximizing yields – you need a specialized adsorption material for this.
Global Adsorbents Pvt. Ltd. manufactures high-purity Activated Carbon for Gold Recovery, for delivering efficient recovery in leaching loops.
Our Gold Recovery Activated Carbons have a homogenous microporous structure because they are made from premium quality coconut shells with high hardness.
This bio-mechanical advantage ensures superior adsorption with high loading capacity, and strength, helping gold mines and gold recovery companies to increase operational efficiency.
The Role of Carbon in Gold Cyanidation
The gold cyanidation process is very important to gold extraction.
During this phase, gold-bearing ore is treated with a dilute sodium cyanide (NaCN) solution in the presence of oxygen. This dissolves the elemental gold, and upgrading it into a stable, water-soluble aurocyanide complex.
Once dissolved, our specialized Coconut Shell-based Activated Carbon for Gold Recovery is introduced to selectively adsorb the gold-cyanide complex out of the liquid phase or abrasive ore pulp.
The porous internal surface of the carbon acts as a molecular magnet, locking the gold ions deep within its micro-pores for downstream elution (stripping) and electrowiring.
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How, Why and Which Extraction Circuits should you use:
CIP vs. CIL versus CIC
To maximize recovery efficiency, matching the correct operational circuit with the appropriate grade of activated carbon for gold recovery is critical.
Key Properties:
Carbon-in-Pulp (CIP) process involves separate Leaching & Adsorption-
How CIP Works: Leaching and carbon adsorption happen sequentially. The ore is fully leached in dedicated agitation tanks first. Then the ore slurry passes into a second circuit where the Activated Carbon for Gold Recovery moves counter-currently to adsorb the dissolved gold.
Active Carbon Requirement for CIP: This needs a high K-Value, equilibrium loading capacity to extract high assays of gold.
Carbon-in-Leach (CIL) involves concurrent leaching and adsorption-
How CIL works: Leaching and adsorption occur simultaneously within the same tanks. Activated carbon is present during the cyanidation process.
Active Carbon Requirement for CIL: Coconut shell carbon of minimum 98% ball pan hardness (ASTM) is suited for this circuit because it mixes with raw ore particles during active leaching, and this carbon has a relatively higher abrasion resistance which is necessary to prevent structural breaks.
Carbon-in-Column (CIC) Involves upward solution flow through carbon columns-
How CIC Works: Value bearing pregnant solutions flow upward through vertical columns which have stationary beds of granular carbon.
Active Carbon Requirement for CIC: This is based on optimal particle size distribution, for example, 6×12 mesh. To maintain ideal solution flow rates without causing pressure drops, bed blinding, or pegging to the screens this works well.
4 Best Practices for How to use Activated carbon for gold recovery to get high levels of extraction rates:
Pre-Screening and De-dusting: Always screen fresh or regenerated Activated Carbon for Gold Recovery over a wet vibratory sizing screen before using it to shed loose carbon dust and other fine particles.
Optimize Slurry Density: Maintain circuit pulp densities for example, between 40% and 45% solids. Screens become weaker because a dense slurry will limit the flow of carbon and slow down adsorption kinetics.
Maintain Counter-Current Inter-stage Flow: Upward movement of carbon from low to high concentration tanks while the ore slurry pumps downstream are important to increase the concentration gradient and load efficiency.
Maintaining Kiln Regeneration Temperatures: When thermally regenerating spent carbon, maintain rotary kiln temperatures in the range of 650°C and 850°C in an oxygen-depleted steam atmosphere. This restores active pore spaces without burning away the carbon’s physical structure.
4 Preventive measures, What NOT to Do while using activated carbon for gold recovery:
Only use coconut base activated carbon: Do not use alternative raw material activated carbon in agitated CIP/CIL circuits. These have relatively lower physical hardness so they can pulverize quickly during agitation. This can lead to more carbon loss and also gold loss.
DO NOT Overlook Inorganic Fouling : Never skip the acid-wash cycle (3% to5% HCl Hydrochloric acid before desorption/elution.)
AVOID Oxygen Depletion in Leaching: If oxygen levels drop below 4 ppm during cyanidation, the gold-cyanide complex will not form properly, and this will stop the Activated Carbon from binding the ions.
Expected Results of Using our activated carbon for gold recovery
High Recovery Yields: Solution-to-carbon gold recovery rates ranging between 95.01% and 99.31%.
Low Gold Loss in Tailings: Hardness numbers of our activated carbon are above 98.5%. This reduces the generation of carbon fines.
Extended Reusability Profiles: Our activated carbon for gold recovery is manufactured with standards to go through 100 to 200 thermal reactivation cycles.
Frequently Asked Questions
Why is coconut shell the best raw material for activated carbon for gold recovery?
Coconut shell when activated with , produces a high volume of micropores (pore diameters less than 2 nm) which match the molecular dimensions of the gold cyanide complex. Besides this, coconut shells possess a very high natural carbonaceous density, which makes its harder when compared to coal or wood based activated carbons. Even among coconut shells, there are special belts in India which have the thickest and hardest shells. Differences in these parameters contribute to significant improvements in the recovery of gold. Global Adsorbents Private Limited have relationships with these farms for the supply of the highest quality raw material.
What is the difference between K-value and R-value in gold-grade activated carbon?
The K-value (equilibrium loading capacity) measures the absolute quantity of gold the activated carbon can hold at saturation, usually expressed in milligrams of gold per gram of carbon. The R-value (adsorption kinetics) measures the speed or rate at which the carbon extracts gold from the solution during initial contact hours. A high R-value is critical in fast-moving CIL circuits where processing time is limited.
Does high attrition resistance prevent loss of gold in mining tailings?
Carbon granules go through attrition scrubbing and agitation. Activated carbon with low hardness, breaks into particles called “fines” – which escape the inter-stage exit screens and into the tailings pond. They contain adsorbed gold, which is lost. It is estimated that every 0.8% to 1.2% of carbon lost to attrition can result in up to 40 to 60grams of gold loss per metric ton of activated carbon. Global Adsorbents Private Limited have special in house techniques to reduce the loss on attrition to the lowest levels in the industry, thus reducing the generation of fines and optimizing recovery of gold.
What are the recommended mesh sizes for gold recovery?
As per global mining standards the mesh sizes are 6×12 mesh (1.70 mm to 3.35 mm) and 8×16 mesh (1.18 mm to 2.36 mm). These sizes provide an optimal surface area required for quicker adsorption kinetics with the structural size needed to remain securely retained by standard industrial inter-stage wedge-wire screens (which generally feature apertures of 0.6 mm to 1.0 mm).
What is carbon poisoning or fouling in gold processing circuits and its cause?
Carbon fouling is caused by the accumulation on the carbon’s surface of inorganic substances like salts, silica and carbonates and iron OR organic compounds for example reagents, oils, and fuels. These block the entrance to the micropore network and prevent the gold-cyanide complex from adsorbing and lowering loading rates.
How many cycles can coconut shell-based activated carbon for gold recovery be reactivated?
It is resistant to structural degradation, it can withstand repeated acid washing and pyrogenic rotary kiln treatment.
Why is acid washing of activated carbon done before elution?
Acid washing with a 3% to 5% Hydrochloric Acid (HCl) solution dissolves inorganic calcium carbonate scale, mineral salts, and metal complexes that may stick to the carbon surface. Removing these inorganic blockages before the stripping (elution) process improves desorption efficiency and keeps the pore structure clean for reactivation.
Does platelet content affect the efficiency of activated carbon for gold recovery?
Platelets are flat, elongated, or flake-like carbon particles created during manufacturing or handling. Despite having good chemical activity, platelets tend to align parallel to screen slots and slip through inter-stage sieves, causing significant gold losses. Global Adsorbents maintains a strict quality control threshold, limiting platelet content to less than 1.0% to safeguard process yields. We have collaborated with gold miners to customize sieve dimensions for them to remove platelets as per their process.
Platelets are flat, elongated, or flake-like carbon particles created during manufacturing or handling.
Despite having good chemical activity, platelets tend to align parallel to screen slots and slip through inter-stage sieves, causing significant gold losses.
Global Adsorbents maintains a strict quality control threshold, limiting platelet content to less than 1.0% to safeguard process yields. We have collaborated with gold miners to customize sieve dimensions for them to remove platelets as per their process.