# Carbon in Column Gold Recovery: CIC Design, Carbon Selection and Troubleshooting
- Publisher: YELI Carbon (Xiamen Yeli New Materials Co., Ltd)
- Published: 2026-10-27
- Last reviewed: 2026-10-27
- Canonical: https://www.yelicarbon.com/blog-carbon-in-column-gold-recovery.html
## Direct answer
Carbon in column (CIC) gold recovery passes a clarified gold-bearing solution through granular activated carbon held in one or more columns. The carbon remains in the column while solution flows through it. CIC selection therefore depends on mesh distribution, bed voidage, pressure drop, fines, fouling, solution chemistry, and compatibility with elution and regeneration, not on iodine value alone.
## What is carbon in column gold recovery?
Carbon in column is a gold adsorption process in which a gold-bearing solution passes through granular activated carbon held in a column or engineered bed. It is used where the feed can be clarified before adsorption, such as some heap-leach solutions, filtered leach liquors, or other low-solids process streams.
In carbon-in-pulp (CIP) and carbon-in-leach (CIL), carbon moves through agitated tanks containing ore pulp. In CIC, carbon normally remains in a packed or engineered column while a comparatively clear solution flows through it.
## CIC vs CIP vs CIL
| Feature | CIC | CIP | CIL |
|---|---|---|---|
| Carbon location | Column or engineered fixed/expanded bed | Agitated adsorption tanks | Agitated leach and adsorption tanks |
| Feed condition | Clarified solution, low suspended solids | Ore pulp | Ore pulp |
| Main strength | Clear separation of solution and carbon; compact contactor | Direct treatment of leached pulp | Leaching and adsorption in one stage |
| Main constraint | Solids, scale, and fines can foul the bed | Screening and carbon attrition in pulp | Screening, aeration, and competing leach conditions |
| Data needed | Flow, bed dimensions, pressure drop, backwash design | Pulp flow, solids, screens, tank profile | Pulp flow, leach kinetics, carbon profile |
Related YELI guide: https://www.yelicarbon.com/blog-cic-vs-cip-cil-gold-recovery.html
## Which activated carbon should a CIC plant evaluate?
A CIC plant should evaluate activated carbon as both a hydraulic and metallurgical material. Ask for:
- particle-size distribution, including fines and oversize limits
- apparent or bulk density and the measurement basis
- ball-pan hardness and abrasion resistance
- moisture and ash
- iodine number and test method
- any gold adsorption rate or capacity result, with test conditions
- exact-lot batch COA and retained sample availability
Coconut shell granular activated carbon is widely used for gold recovery because its hard structure and microporous surface suit the gold cyanide complex. Nominal mesh alone does not prove suitability. A 6x12 mesh cut may suit a column where that particle size retains properly and the pressure-drop budget allows it; a finer or coarser cut may be appropriate in another design.
YELI's published gold-grade coconut shell GAC range is 6x12 mesh and 8x16 mesh, with 3x6 mm also available, iodine 1000-1300 mg/g, ball-pan hardness >=98%, and a batch COA. These figures are a starting specification, not a substitute for testing the delivered lot against the plant's actual solution.
## How does mesh size affect pressure drop?
Finer carbon creates more particles and smaller flow channels per unit of bed volume, so pressure drop can rise at the same superficial velocity. A wide particle-size distribution can make the effect worse because small particles migrate into the voids between larger granules.
Mesh size alone does not predict pressure drop. Bed voidage, particle shape, fines, feed solids, bed depth, flow rate, temperature, support design, and flow distribution also matter. Record pressure differential at several flow rates and after backwashing during commissioning.
Related YELI guides:
- https://www.yelicarbon.com/blog-gold-carbon-mesh-size-guide.html
- https://www.yelicarbon.com/blog-activated-carbon-packed-bed-voidage-gold.html
## How should a CIC column calculate bed voidage?
Bed voidage is the fraction of packed-bed volume not occupied by carbon particles.
A practical estimate is:
`voidage = 1 - (bulk density / particle density)`
Both densities must come from the same conditioned sample and state the same measurement basis. Bulk density is carbon mass divided by settled bed volume. Particle density excludes spaces between particles but includes internal pores according to the stated method.
If particle density is unavailable, voidage should be measured or supplied as design data rather than guessed from a typical number. Request the method and sample condition behind each density value.
YELI specification sheet: https://www.yelicarbon.com/gold-carbon-specification-sheet.html
## Common carbon-in-column problems
| Symptom | Check first | Useful evidence |
|---|---|---|
| Pressure differential climbs | Feed solids, fines, bed compaction, gas pockets, scale | Pressure trend at fixed flow; differential after backwash; sieve analysis |
| Gold breakthrough arrives early | Flow, contact time, bed bypass, feed grade, carbon condition | Inlet/outlet assays; loading profile by bed depth; flow record |
| Uneven carbon loading | Distribution, channeling, bed level, column geometry | Depth samples; hydraulic study; shutdown inspection |
| Fines appear after transport | Hardness, abrasion resistance, dust, handling | Batch COA; sieve test before/after handling; photo log |
The column design basis should state acceptable flow ranges, bed expansion limits, and the action to take when pressure trends move outside the approved window.
## Loading, stripping, and regeneration
Column carbon should be evaluated against the entire route:
- loading kinetics
- elution performance
- acid-wash or scale-control requirements
- regeneration temperature
- handling losses
- expected useful cycles
A carbon that loads well but breaks down during transfer can create a downstream gold-loss problem that a loading test alone will not reveal.
Related YELI guides:
- https://www.yelicarbon.com/blog-gold-carbon-elution-guide.html
- https://www.yelicarbon.com/blog-gold-carbon-regeneration-cycles.html
## Batch COA checks
A useful batch COA connects the tested sample to the shipment and states the method, result, and acceptance limit for each property.
Check:
- mesh distribution
- iodine number
- ball-pan hardness or abrasion resistance
- apparent density
- moisture and ash
- gold adsorption rate or capacity, if reported
- lot number matching bags, pallets, and shipping documents
- whether the result is a single batch or composite
- retained sample availability
Primary references:
- ASTM D4607 iodine number: https://www.astm.org/d4607-14r19.html
- ASTM D3802 ball-pan hardness: https://www.astm.org/d3802-10r24.html
- YELI sample COA: https://www.yelicarbon.com/coa-sample-gold-carbon.html
## Buyer data checklist for a CIC carbon quotation
Send:
1. Circuit route and whether the feed is truly clarified.
2. Solution flow in m3/h, operating hours, gold tenor, pH, temperature, cyanide, and suspended solids.
3. Column diameter, bed depth, number of columns, design pressure drop, flow direction, and backwash design.
4. Support, screen, and distribution details.
5. Whether carbon is stripped in place or transferred.
6. Elution, acid-wash, and regeneration conditions.
7. Required mesh distribution and acceptable fines.
8. Iodine, hardness, density, moisture, and ash limits.
9. Packing, port, target trial quantity, and delivery schedule.
10. Previous COA or operating problem, if available.
Quote request: https://www.yelicarbon.com/contact.html#quote-form
## CIC pilot test
Use a representative solution or an approved synthetic solution. Run candidate carbons under the intended flow and temperature, with the same bed depth and preconditioning where practical.
Measure:
- pressure drop at several flow rates before loading
- outlet assays over time for breakthrough curves
- loaded-carbon gold profile through the bed
- elution performance
- regeneration performance
- changes in particle-size distribution and fines
A pilot that reports only one adsorption number does not answer whether the bed is hydraulically stable or whether the loaded carbon can be stripped and reused.
## Technical references
- ASTM D4607: Standard Test Method for Determination of Iodine Number of Activated Carbon
- ASTM D3802: Standard Test Method for Ball-Pan Hardness of Activated Carbon
- YELI specification sheet: https://www.yelicarbon.com/gold-carbon-specification-sheet.html
- YELI sample batch COA: https://www.yelicarbon.com/coa-sample-gold-carbon.html
- Packed-bed voidage guide: https://www.yelicarbon.com/blog-activated-carbon-packed-bed-voidage-gold.html
- Gold carbon mesh guide: https://www.yelicarbon.com/blog-gold-carbon-mesh-size-guide.html
## Contact
- Email: info@yelicarbon.com
- WhatsApp: +86 136 0090 6330
- Product hub: https://www.yelicarbon.com/activated-carbon-gold-recovery.html
- Quote form: https://www.yelicarbon.com/contact.html#quote-form