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Calcium Carbonate · Grade Selector

Which calcium carbonate grade does your application need?

Grade selection is a particle-size decision: match the top cut (D97) to your product's gauge. The thinner and glossier the product, the finer the grade — a coarse particle that causes no problem in a pipe wall becomes a gel, speck, or tear in a thin film. Whiteness does not enter the choice: every grade in the KC Series runs whiteness ≥98 and ISO brightness ≥95.

Pick your application below and get the grade a technical rep would start with, plus the one-line reason. The recommendation is a starting point — the free sample is what settles it on your own line.

Pick an application above to get a grade. The selector applies one rule: match the top cut (D97) to your product's gauge — the thinner and glossier the product, the finer the grade.

The KC Series ladder — finest to coarsest

KC-4

D97 ~5.5 µm

Finest cut

KC-6

D97 ~6 µm

Fine

KC-10

D97 ~10 µm

General-purpose middle

KC-17

D97 ~17 µm

Coarse & economical

Every grade, same chemistry — the ladder is a particle-size decision

CaCO₃ ≥98%

Fe₂O₃ ≤0.05%

Whiteness ≥98

ISO brightness (R457) ≥95

Surface Coated or uncoated

Values typical, confirmed per lot on the certificate of analysis. The accredited heavy-metals panel is in progress and will be supplied with the COA once complete — relevant if your end-use is food-contact.

Qualify it on your own line

A free sample (under a tonne) with a per-lot certificate of analysis, dispatched within 48 hours. Your application comes with the request, so the sample matches your line — not a generic pack.

A recommendation, not a quote — no obligation. Your selection is used only to match the sample to your line. See our privacy policy.

The full logic

Which grade for your application? The particle-size guide →

Running a white product?

Run the TiO₂ economics on your own numbers →

The selection logic

Top cut matters more than the average — defects come from the coarse tail

The number that predicts defects is not the median particle size (D50) — it is the top cut (D97), the size below which 97% of the particles fall. Two grades can share a similar average and behave very differently if one has a longer coarse tail. That is why the selector matches D97 to gauge: the thinner or more surface-critical the product, the tighter the top cut it needs.

It is also why "just use the finest grade everywhere" is a mistake. An ultrafine grade in a thick pipe wall adds cost and can make dispersion harder — finer particles agglomerate more — without improving the part. The right grade is the coarsest one your product's gauge tolerates, at the best economics.

Kantor Materials produces the KC Series at the Yên Bái limestone belt in Vietnam and supplies it producer-direct. The full reasoning behind the ladder is in the grade-selection guide; if your line is white, the filler economics calculator shows what the ≥98 whiteness is worth in displaced titanium dioxide — on your own numbers.

Frequently asked

How does the grade selector choose a calcium carbonate grade?

It applies the same rule a technical rep would: match the top cut (D97) to the product's gauge and surface demands. Thinner and glossier products need a finer, tighter cut (KC-4, KC-6); thicker, less surface-critical products are more economical on a coarser grade (KC-10, KC-17). Defects come from the coarse tail of the particle-size distribution, so the top cut — not the average size — is the number that predicts them.

What is the difference between KC-4, KC-6, KC-10, and KC-17?

Particle size only. KC-4 is the finest cut (D97 about 5.5 µm) and KC-17 the coarsest (D97 about 17 µm). Chemistry and whiteness are the same across the ladder: CaCO₃ ≥98%, Fe₂O₃ ≤0.05%, whiteness ≥98, ISO brightness (R457/ISO 2470) ≥95, available coated or uncoated. Values are typical and confirmed per lot on the certificate of analysis.

Is the recommended grade final?

No — it is the grade a technical rep would start with. Formulations, equipment, and loadings differ, so the grade is settled on your own line: Kantor Materials dispatches a free sample (under a tonne) with a per-lot certificate of analysis within 48 hours for your lab to qualify against what you run today.

Do I need coated or uncoated calcium carbonate?

That is a separate decision from the grade number — it follows your loading, gauge, and dispersion process. The general rule: the higher the loading, the thinner the product, and the finer the grade, the more benefit a stearic-acid coating gives. For low loadings in thick products, uncoated is usually fine. Every KC grade is available both ways.

What if my application is not listed?

Send the application, the gauge or wall thickness, and the spec you run today — the grade follows directly from those three. Request a sample through the selector and reply with the details, or use the inquiry page; we will recommend the grade and send a free sample with a per-lot COA to qualify on your equipment.