A trial-lot plan to qualify a charcoal supplier

Changing a raw material supplier is one of the riskier moves in a carbon plant. A new charcoal can behave differently in the furnace, and the surprise often comes after the first full cargo has arrived. A trial-lot plan turns that risk into a series of small, cheap tests, each with a clear pass or fail. This note shows how to qualify a charcoal supplier in six stages, for a processor evaluating Kora or any other source of coconut shell charcoal. Kora supplies charcoal and powder only, and does not make or sell activated carbon.

Stage 1. Paper review

Before anything is shipped, compare the supplier’s published data with your specification.

• Take the limits Kora publishes for lump charcoal: fixed carbon at least 70 %, moisture up to 10 %, ash up to 5 %, grades A and B, jumbo bag packing, about 13 MT in a 20-foot container.
• Mark the rows of your specification that Kora does not answer. For lump these are volatile matter, size spread and hardness. For powder, fixed carbon, ash, bulk density and particle size distribution.
• Ask what the difference between Grade A and Grade B is. Kora gives that on request.

Outcome: a short list of questions and a decision whether to continue. If a missing row is critical for your process and the supplier cannot provide it even by testing, stop here.

Stage 2. Sample and laboratory report

Request a sample, and ask for the laboratory report and the certificate of analysis (COA) of the lot it came from. Then run your own tests on the same sample.

• Use the method and basis named in your specification.
• Test enough pieces to see the spread, not only the average.
• Record the sample’s lot identification so you can trace it.

Outcome: a comparison of three sets of numbers: published limits, supplier report, your own result. They should tell the same story. If they do not, ask why before you go on.

Stage 3. Small activation test

If your plant allows, run a small activation batch with the sample. Measure what you normally measure on your product. This is the real qualification; everything else is preparation. A sample can pass every paper limit and still behave differently in your furnace, which is why the written limits come from your process.

Outcome: a yes, a no or a “yes with conditions”, where conditions become contract terms such as a tighter size range.

Stage 4. Trial lot

Order a modest quantity, below a full container if the terms allow, and treat it as an inspection exercise.

• Agree the incoterm and payment method up front. Kora states FOB or CIF at an Indonesian port; letter of credit at sight, telegraphic transfer or escrow-protected payment; and documents against payment for established buyers.
• Ask for the five documents Kora states with each shipment: COA, phytosanitary certificate, certificate of origin, packing list and bill of lading.
• Confirm with your forwarder, before booking, how your cargo is treated under dangerous-goods rules and which customs heading applies. Kora’s pages do not state either.
• On arrival, sample each bag group and test the same properties you tested in stage 2.

Outcome: a comparison of the arrived lot with the sample and with the COA.

Stage 5. Write acceptance criteria

From stages 2 to 4, fix what a delivery must meet:

1. the limits, with method and basis;
2. the sampling rule, such as how many bags are tested for each lot;
3. what happens when a lot is outside the limits: replacement, price adjustment or rejection;
4. the time allowed to make a claim.

Stage 6. Routine control

After qualification, keep two habits:

• check every incoming lot against its COA, and keep the samples for an agreed period;
• review the results every quarter or after a process change, and raise drift early.

Where to begin

To qualify a charcoal supplier, stage 1 costs nothing but time. Send your specification, even if incomplete, through the contact page, and read the published figures on the lump charcoal feedstock page. The first reply comes within two business days.