By the YELI Technical Team · Updated August 2026 · 6 min read
Short answer: For gold CIP/CIL recovery, the three common coconut-shell GAC cuts are 6×12 mesh (particles ~1.7–3.4 mm, the most widely used all-rounder), 6×16 (~1.2–3.4 mm, finer, for tighter screens and slower flows), and 3×6 mm (~3.4–6.7 mm, coarse, for high-flow or pre-regeneration duty). Choose the cut that matches your interstage screen apertures and elution column — changing mesh later is a plant redesign, not a swap. If in doubt, 6×12 is the safe default for most CIP/CIL circuits.
Mesh size is the most overlooked specification in gold carbon buying. Buyers focus on iodine and hardness, then discover the 6×12 they ordered doesn't match their interstage screens or their elution column's flow characteristics. Mesh is not a preference — it is a compatibility decision with your entire circuit. Here is how the common cuts compare and how to choose.
What the Numbers Mean
Mesh numbers describe the particle size range. "6×12" means particles pass a 6-mesh screen (3.4 mm openings) but are retained on a 12-mesh screen (1.7 mm openings) — so particles are roughly 1.7–3.4 mm. Larger numbers mean finer particles. The size affects three things: how carbon behaves on your interstage screens, how it packs in the elution column, and how it survives the kiln.
The Three Common Cuts Compared
| Cut | Particle size | Typical use | Notes |
|---|---|---|---|
| 6×12 mesh | ~1.7–3.4 mm | Most CIP/CIL circuits | All-rounder; matches standard interstage screens; good loading and elution flow |
| 6×16 mesh | ~1.2–3.4 mm | Finer screens, slower flow | More surface area per volume; tighter screens required; higher pressure drop |
| 3×6 mm | ~3.4–6.7 mm | High-flow, pre-regeneration | Coarser; lower pressure drop; less surface area per volume |
Why the Cut Must Match Your Screens
Interstage screens are sized to retain the carbon in each tank. If you order finer carbon than the screens allow, it escapes with the pulp — carrying adsorbed gold with it. If you order coarser carbon than your elution column is designed for, flow characteristics change and elution efficiency drops. The sieve analysis on the COA tells you the actual distribution; ask for it and check it against your circuit before ordering.
Mesh and Elution: The Less Obvious Link
Elution columns are designed around a bed of a certain particle size. Finer carbon packs more densely, which raises pressure drop and can change how evenly the eluant flows through the bed. Coarser carbon flows more freely but offers less surface area for gold transfer. This is why changing mesh later is disruptive — the column, screens and kiln were all designed around the original cut.
Mesh and Regeneration
In the kiln, finer particles are more vulnerable to burn-off and loss through the discharge screens. Coarser carbon generally survives regeneration with less loss. If you run many regeneration cycles, the slightly coarser end of your range tends to last longer — another reason the 6×12 default balances surface area and durability.
Which Should You Buy?
- 6×12 mesh — the safe default for most CIP/CIL plants. If you don't have a strong reason to deviate, start here.
- 6×16 mesh — choose when your interstage screens are fine and flow is low enough to tolerate higher pressure drop.
- 3×6 mm — choose for high-flow circuits or as a pre-regeneration coarse cut where pressure drop must stay low.
Tell your supplier your screen apertures and elution setup, and they should confirm the right cut rather than selling you a default.
Need the Right Cut for Your Circuit?
We supply gold-grade coconut shell GAC in 6×12, 6×16 and 3×6 cuts — iodine 1000–1300, hardness 95–98%, full sieve analysis with every batch. Tell us your screens and elution setup and we will confirm the grade.
See Gold CIP/CIL Grade Specs →The Bottom Line
Mesh size is a compatibility decision, not a preference. Match the cut to your interstage screens, elution column and regeneration kiln — and verify the sieve analysis on every lot. When in doubt, 6×12 is the all-rounder most circuits use. For the full spec picture, see our gold CIP/CIL grade page.
FAQ: Gold Carbon Mesh Size
6×12 mesh (particles ~1.7–3.4 mm) is the most widely used all-rounder for CIP/CIL circuits and the safe default for most plants. 6×16 is finer (more surface area, tighter screens required) and 3×6 mm is coarser (lower pressure drop, high-flow duty). Match the cut to your interstage screens and elution column.
6×12 means particles pass a 6-mesh screen (3.4 mm openings) but are retained on a 12-mesh screen (1.7 mm openings), so particles are roughly 1.7–3.4 mm. Larger numbers mean finer particles. The sieve analysis on the COA shows the actual size distribution.
Changing mesh is a plant redesign, not a swap — interstage screens, elution column and kiln are all designed around the original cut. Choose the right mesh from the start, and verify the sieve analysis on every lot.
Yes. Finer particles are more vulnerable to burn-off and loss through kiln discharge screens, while coarser carbon generally survives regeneration with less loss. That is another reason the 6×12 default balances surface area and durability over many cycles.