Granular Activated Carbon Supplier: How to Spec and Source GAC from China

This page is written for the person who has to place the order: what the numbers on a GAC datasheet actually control, how to match raw material to application, and how to vet a Chinese GAC manufacturer before you wire a deposit. If you want the engineering side — bed depth, EBCT, vessel sizing — that lives in our GAC system design guide. If you want per-ton numbers, see the activated carbon price guide.

What Granular Activated Carbon Is

GAC is activated carbon crushed and screened into irregular granules, typically between 4 and 40 mesh, then steam-activated at 800–1000°C to open up an internal pore network of 800–1200 m²/g. The granular form exists for one reason: it holds together in a packed bed under continuous flow, so water or gas can pass through at pressure without the media compacting, blinding, or washing out.

That is the dividing line against the other two forms. Powdered carbon is dosed into a tank and removed with the sludge — it works fast, but you can't run flow through it. Pellet carbon is extruded into uniform cylinders with a lower pressure drop, which matters in gas phase. GAC sits in the middle and dominates liquid-phase filtration: municipal drinking water, industrial wastewater polishing, point-of-use cartridges, gold recovery columns, sugar and sweetener decolorization.

How to Read a GAC Datasheet

Most GAC disputes trace back to a buyer who compared only iodine number. These are the parameters that decide whether the carbon performs, in the order they usually matter.

Iodine number (mg/g)

The standard proxy for total micropore surface area, measured by iodine adsorption. Higher iodine means more capacity for small molecules. Our coal-based HojeeAqua BG series runs BG400 through BG1000 (iodine >500 to >1000 mg/g); coconut-shell HojeePure CG grades run CG950 to CG1100 (iodine >950 to >1100 mg/g).

Iodine number is necessary but not sufficient. It tells you nothing about pore size distribution, so it over-predicts performance on large molecules — humic acids, color bodies, PFAS — which need mesopores the iodine test never sees.

Bulk density (kg/m³)

The parameter buyers forget and then get burned by. GAC is sold by weight and used by volume. A vessel holding 10 m³ of media needs 4,800 kg of a 480 kg/m³ coconut carbon, but 6,600 kg of a 660 kg/m³ coal carbon — a 37% difference in tonnage on the same purchase order.

Typical ranges: coconut-shell GAC 480–520 kg/m³, coal-based GAC 450–660 kg/m³ depending on grade, wood-based lower still. Always confirm the figure before you compare quotes per ton, because a cheap high-density carbon can cost more per cubic metre of bed filled.

Hardness and abrasion

How much of the granule survives handling, backwash and thermal reactivation. Coconut GAC typically tests above 98–99% hardness; our coal-based grades hold above 95%. Soft carbon generates fines, fines cause head loss and turbidity spikes, and if you plan to reactivate, soft carbon means you lose several percent of the bed every cycle. See the hardness and abrasion number guide for the test methods.

Ash and water-soluble content

Ash is the inorganic residue left after the carbon burns off. Coconut shell GAC runs under 3%; coal-based GAC typically under 12%. High ash means more leachable minerals, higher pH drift on start-up, and in gold recovery, more contaminants competing for adsorption sites. For drinking water and food contact, low ash plus low water-soluble content is what keeps you inside the spec.

Mesh size and uniformity

Mesh controls the trade-off between adsorption kinetics and pressure drop. Finer mesh adsorbs faster with more external surface; coarser mesh runs at lower head loss. What matters as much as the nominal size is how tightly the distribution is held — a sloppy 8×30 with 10% oversize and 8% fines will channel. Ask for the actual screen analysis, not just the label. Our mesh size guide maps common cuts to applications.

Moisture

Usually specified at ≤5%. It matters because you pay for it. Carbon shipped at 12% moisture instead of 5% means roughly 7% of every container is water.

Matching Raw Material to Application

There is no universal GAC. Three raw materials, three pore structures, three price points.

Coconut shell GAC is micropore-dominated, hard, and low in ash. It is the default for drinking water, point-of-use cartridges, food and beverage, and gold recovery, where hardness and cleanliness carry the decision. Iodine typically 950–1200 mg/g.

Coal-based GAC has a broader pore distribution reaching into the mesopores, which makes it stronger on larger organic molecules, color, COD and taste-and-odour work in municipal and industrial water. It is also meaningfully cheaper per ton. Our coal granular grades cover iodine >500 to >1000 mg/g across the BG range. The coal-based activated carbon guide breaks down the sub-grades.

Wood-based GAC is macropore-heavy and mostly used where decolorization drives the spec rather than filtration.

A short version: if it goes in a drinking water cartridge or a CIL circuit, start with coconut. If it polishes municipal or industrial water at volume, start with coal and let the pilot data decide. For the full comparison, see coconut shell vs coal-based activated carbon.

Grade Selection by Use Case

Gold recovery is the one case where iodine number is the wrong yardstick. Loading capacity (K value), kinetics (R value), hardness and attrition decide the result — see the 6×12 gold recovery carbon specifications.

How to Vet a Chinese GAC Manufacturer

China supplies the majority of the world's granular activated carbon, and the quality spread between the best and worst factories in the same city is wider than most buyers expect. Five checks separate a manufacturer from a trading desk.

1. Ask whether they own the kiln. A large share of "manufacturers" on B2B platforms are traders reselling whichever factory quoted lowest that week, which is why batch consistency collapses on the second order. Ask which activation furnaces they run, how many production lines, and annual tonnage. We operate three production bases — Nan'an in Fujian, Shizuishan in Ningxia, and Hami in Xinjiang — with 20,000+ tons of annual capacity, which is also what lets us hold one spec across repeat orders.

2. Demand a batch-specific COA, not a sample COA. The meaningful document is the certificate of analysis for the lot you are shipping, tested against the parameters in your PO: iodine, bulk density, hardness, ash, moisture, screen analysis. A generic datasheet with round numbers proves nothing. Every batch we ship carries its own COA.

3. Verify certifications by number. ISO 9001/14001/45001 certificates carry registration numbers you can check. Ours is ISO 9001:2015 No.00125Q36671R0S, issued by CQC. Food and drinking water work may additionally need Halal, Kosher, or food-grade documentation — ask upfront rather than after production.

4. Allow third-party pre-shipment inspection. A factory confident in its carbon will accept SGS or BV inspection of the loaded lot before it sails. A factory that resists is telling you something. We offer SGS/BV pre-shipment inspection on request.

5. Test the sample against your own water. Lab numbers are a screen, not a decision. Get 5–25 kg of the actual production grade, run it on your feed, and compare breakthrough against your incumbent carbon. Anyone unwilling to send a real sample from a real batch is not a supply partner.

MOQ, Packaging and Lead Time

MOQ is 1 ton on most GAC grades, which is deliberately low so you can qualify the carbon before committing to a container. Full-container load — roughly 20+ tons in a 20ft, up to 28 tons in a 40HQ depending on bulk density — gets the best per-ton rate.

Packaging options:

• 25 kg woven bags with inner PE liner, palletized — standard for cartridge and small-batch users
• 500 kg and 1,000 kg FIBC jumbo bags — lowest cost per ton for bulk vessels and distributors
• Custom-printed OEM packaging with your brand

Lead time runs 7–15 days for stock grades and 15–25 days for custom specifications or OEM packaging. We ship to 50+ countries on FOB, CIF and DDP terms. Recent GAC movements include 78 tons of coal GAC to Myanmar for water treatment and coal GAC to Saudi Arabia for municipal supply — the case studies carry the loading and documentation detail.

Frequently Asked Questions