How to Verify a Chinese Activated Carbon Factory Is Real: A 15-Question Factory Audit

By the YELI Technical Team - Updated October 2026 - 8 min read

Short answer: Four checks separate a Chinese activated carbon factory from a trading company: an 18-character unified social credit code that resolves to an active licence with a manufacturing scope, live video of a steam activation kiln running, a lab that titrates its own iodine number, and a customs declaration naming the company as the producer of the goods. A coconut-shell gold carbon factory sells 6×12 mesh (1.70–3.35 mm, GB/T 12496.2 / ASTM D2862) at iodine 1000–1300 mg/g (GB/T 12496.8 / ASTM D4607), hardness ≥98% (GB/T 12496.6 / ASTM D3802), platelet content <1.5% and apparent density 0.45–0.52 g/cm³ (GB/T 12496.1 / ASTM D2854). If those numbers cannot be tied to a test method, a batch number and a dated COA, keep your deposit in your own bank.

Most suppliers who answer an activated carbon RFQ within ten minutes are not factories. In China the export side of this trade is dominated by trading companies registered in Xiamen, Qingdao, Guangzhou and Tianjin, while the plants that steam-activate coconut char sit inland in Fujian, Jiangxi, Hainan and Ningxia. A trader is not automatically a problem — a competent one is a workable partner if you know which plant runs your batch. The problem is that from an email signature you cannot tell the two apart, and a deposit wired to the wrong one is hard to recover from 8,000 km away.

How do you tell a Chinese activated carbon factory from a trading company?

A factory answers process questions. A trader answers price questions. Ask what the carbon looks like when it leaves the kiln, before screening — a plant manager describes the discharge, the temperature and the fines. Ask for the steam-to-char ratio, how the kiln is fired, or how many tons of coconut char are in the yard today, and you get a number in the answer. Ask a trader and you get "our engineer will confirm", followed two days later by a PDF datasheet.

The most reliable test is to request something they cannot copy: the QC log page covering the last ten production lots, with batch numbers and the measured iodine, hardness, apparent density, moisture and ash for each. A plant produces that page every day. A trader has never produced a line of it.

Ask for the specification in method terms, not in words:

A second useful test is the negative question: what can you not do? A real plant names the cuts it does not run, the highest iodine its char can reach, and how long a production run takes. A trader says yes to everything, including a 4×8 cut at iodine 1200 mg/g delivered in a week.

Check the licence, the credit code and the bank account name

Read the business licence in this order: legal name, unified social credit code, company type, registered address, business scope, date of establishment, registering authority. The scope is where the truth sits. A manufacturer's scope contains production and processing of activated carbon; a trading company's contains wholesale, retail, commission agency and import/export. Both are legal entities. Only one owns a kiln.

Then verify the code yourself instead of trusting the scan. The National Enterprise Credit Information Publicity System (gsxt.gov.cn) returns the live record for the 18-character code: operating status, address, scope, and whether the company has been placed on the abnormal operation list for a missed annual report or an address it no longer occupies. If the code returns nothing, or the name does not match your proforma invoice, stop.

Registered capital proves nothing — it is a subscribed figure that says nothing about kilns, and it is the number traders quote most often. Look instead for an address a plant can occupy: a village or township industrial road, not a room on the 26th floor of an office tower.

The bank details end most conversations. Compare three names: the legal name on the licence, the beneficiary on the proforma invoice, and the account name in the bank details. They must be identical. If you are asked to wire to a personal account, to a company registered in another city, or to an offshore account you have never seen on any document, walk away — you lose the VAT invoice, the paper trail and any realistic claim in China. Check the beneficiary address in the SWIFT field against the licence address too.

Ask for the ISO 9001 certificate and verify the number with the issuing body, or on the CNCA platform (cx.cnca.cn). Then check the certified address. A certificate issued to another company at another address is not evidence about your supplier, however good the scan looks.

Does the plant address match the port on your bill of lading?

Longyan has no seaport, and neither does Ningxia or Jiangxi. Coconut shell activation plants sit inland because char, fuel and labour are there, and containers move by truck to Xiamen, Fuzhou, Qingdao or Tianjin. An inland address is normal. An inconsistent story is not.

Send three questions in one email: the plant address in Chinese characters, the port of loading they will quote FOB from, and the freight forwarder they use there. A factory answers all three in one line and can add the trucking time, whether the container is loaded at the plant or stuffed at a port-city warehouse, and how the bags are palletised. A trader quotes whichever port is cheapest that week, and the "factory address" changes between emails.

Cross-check one address four times: on the licence, on the ISO 9001 certificate, on the COA header and on the packing list. A real plant's address is identical in all four.

Then read the export paper. On a Chinese customs declaration, 境内发货人 names the domestic consignor and 生产销售单位 names the producer of the goods. Ask for two redacted declarations from the past year where their own company appears in the production and sales field, for activated carbon under HS code 3802.10.00. A supplier who cannot show one declaration carrying their own name has not exported anything, whatever the website says.

Loading is the last link in that chain. Ask for loading supervision at the plant, with the container and seal numbers visible in the photographs and the bags counted as they go in. If the cargo must be "consolidated" elsewhere and nobody may watch, the lot you approved may not be the lot in the container.

Weight is where this turns into money. Packing is normally 25 kg film-laminated woven bags or 500–1,000 kg jumbo bags with a liner, and 10 m³ of carbon weighs about 4,500 kg at 0.45 g/cm³ but 5,200 kg at 0.52 g/cm³ — roughly 700 kg, or 15%, on the same volume. Ask for charge mass calculated from measured density, and treat a bag packed below its nominal net weight as a claim against the moisture and density figures on the COA.

Do they own a steam activation kiln and a coconut-shell supply?

Gold recovery carbon is physically activated with steam in a rotary kiln or a multiple-hearth furnace. Chemical activation with phosphoric acid or zinc chloride is a different process, used mostly for wood-based carbons, and it leaves a different pore structure plus residues you do not want upstream of a CIL circuit. Ask directly which route they use, then for the kiln type, the fuel, the number of kilns and whether they are running today.

Photographs prove nothing — every trader owns a folder of another plant's photographs, watermarks included. Ask for a live video call during Chinese working hours and give them a route: start at the plant gate with the company sign in frame, walk to the kiln and show the discharge, open the lab door, finish at the screening deck with 6×12 carbon running. Have them state the date on camera. A real factory does this in five minutes and mildly complains about the walk. A trader asks you to wait until next week and sends more photographs.

Then test their raw material knowledge. Coconut shell char comes from Hainan, Indonesia, the Philippines and Sri Lanka; the shell is carbonised near the source and the char ships to the activation plant. Ask the char origin, how many tons are in the yard today, and whether char is dried before charging — then how they hold iodine between 1000 and 1300 mg/g when char quality varies shipment to shipment. Someone who runs the kiln answers with settings they can defend. Someone selling paper says "high quality raw material".

Screening and de-flaking separate a gold plant from a water plant. The 6×12 cut is made by screening, while flat plate-shaped granules are created in the kiln and removed by water polishing and edge rounding. Ask what they do about platelets, what the last batch measured against the <1.5% limit, and how much −200 mesh fines the screening generates per batch. Flakes pass screens, pack badly in a column and break into fines that leave your circuit carrying gold — loaded carbon commonly assays 3,000–10,000 g Au/t (Industry-typical; not a YELI process commitment.) Ball-pan hardness is the other half of that loss: coconut shell carbon typically runs 96–99% and coal-based carbon 90–95% (Industry-typical; not a YELI process commitment.) Two grades with identical iodine numbers on paper can differ by tonnes of annual consumption.

Is the lab real? Iodine, hardness, density and platelet in-house

Four tests have to run in-house for a plant to control its own product: iodine number by titration (GB/T 12496.8 / ASTM D4607), hardness by the ball-pan method (GB/T 12496.6 / ASTM D3802), apparent density in a graduated cylinder (GB/T 12496.1 / ASTM D2854), and moisture and ash by oven and muffle furnace (GB/T 12496.4 / ASTM D2867, GB/T 12496.3). Platelet content is plant QC rather than a published standard method, so ask how they count it. An answer mentioning a sieve, a counting tray and a technician looking at granules is real. An answer repeating the brochure number is not.

A working iodine bench is easy to recognise: a burette on a stand, iodine standard solution, sodium thiosulfate, starch indicator, an analytical balance with a current calibration sticker, a sieve shaker with the steel balls used for the hardness test, a muffle furnace and a drying oven. Ask for a three-minute video of one titration and the equipment list with model numbers. If the "laboratory" is a colour comparison card or a handheld meter, nobody is measuring iodine; a tolerance of ±50 mg/g on an ordered grade cannot be held by eye.

Outsourcing is a grey area, not a disqualification. A trader can send every sample to a third-party lab and still sell you good carbon — but then nobody in that office knows the iodine of the lot going into your container, and nobody catches a bad batch before it ships.

COA discipline is what you actually buy. A COA worth having carries a batch number, production and test dates, measured values with a pass/fail column against the ordered specification, the test method beside each value, the legal entity name and an authorised signature. Reject documents listing "typical values" instead of batch results, carrying no method column, or promising the COA after payment. Then check paper against material: keep a sealed split of the sample you tested and compare it with your own lab or third-party result on the shipped lot. Iodine outside the stated tolerance band is a rejection, not a negotiation.

Sampling is where most disputes start. Ask how many bags per lot are sampled and how the sample is reduced — quartering or a riffle splitter. A composite drawn from one bag at the top of a stack says nothing about the container.

Can you check all of this without flying to China?

Yes, and you should run most of it before spending money on a visa. The licence and credit code are checkable the same day, the ISO certificate with the issuing body, the video walk in one appointment, the sample by air courier. A site visit is better — stand at the kiln, watch the screening, look at the char yard — but it should confirm a supplier you have already verified, not replace the verification.

Order the sample before you argue about price. Ask for a 1–2 kg composite from the production lot, split into two sealed bags: one for your laboratory or an independent one, one held as your reference. Test iodine, hardness and apparent density, then compare with the COA the factory issues for the same batch number. A sample that arrives without a batch number, or with a COA typed after your enquiry, is a warning rather than a sample.

For a serious order, appoint an inspector — SGS, Intertek, Bureau Veritas or Cotecna — for pre-shipment inspection or loading supervision, and write the scope into the contract: sample from sealed bags, iodine and hardness in a nominated laboratory, witnessed stuffing, sealed and photographed container. A plant that owns the material accepts this within a day. The fee is small against a container.

Then read the export record: the commercial invoice, packing list, bill of lading, certificate of origin and COA of one delivered shipment, with the shipper name on the bill of lading matching the legal name on the licence. Then call the forwarder named on the booking and ask whether they handle this company's carbon regularly and where they receive it. Forwarders answer honestly; they have no stake in the sale.

Payment structure is part of verification. Never wire the full value to a supplier you have not met, and never to a personal account. A letter of credit at sight from a bank both sides accept, or a deposit against shipping documents, are ordinary here; a supplier who refuses every structure that gives you a document check is telling you something. The comparison of terms is in payment terms for activated carbon from China.

The 15-question audit list, and the answers traders give

Send all fifteen in one email rather than one at a time. Response time, completeness and the use of the supplier's own words tell you as much as the content.

Now the other side. These are the sentences you will hear most often, what they usually mean, and what to do next.

One last habit: compare the answers across emails. The address, the port, the forwarder, the kiln count and the char origin should be identical every time you ask. A supplier whose story moves is a supplier whose carbon will move too.

Frequently asked questions