What is the difference between D50 and D97?

D50 is the median particle size: half the particles are finer. D97 is the top cut: 97% of particles are finer than this value. Our grades are named by their nominal top cut, from 5 to 20 microns, and both values are measured by laser diffraction.

Are coated and uncoated grades the same base mineral?

Yes. Both series start from the same ground calcium carbonate at 99.9% purity and 97% brightness. The coated series adds a stearic acid surface treatment, with the coating level measured by thermal analysis on every grade.

How is the stearic coating level verified?

By a thermal mass-loss method: the sample is dried at 105 °C, then treated at 350 °C in a muffle furnace, and the mass difference gives the exact stearic acid percentage.

Can I get a full laboratory report for a specific grade?

Yes. Each grade has a technical data sheet available for download, and full laser-diffraction particle size reports are available on request.

Clear Technical Data

The numbers, side by side.

Review the key product specifications and compare grades to choose the right option for your application.

Particle Size Distribution

A clear comparison of available particle sizes.

Particle-size comparison (µm)
Grade (top cut)	D50 · Median	D90	D97	D98	Coating*	TDS
CaCO₃ — 5 µm	1.52	3.46	4.10	5.25	1.47%	Download
CaCO₃ — 8 µm	2.10	5.94	8.05	8.71	1.36%	Download
CaCO₃ — 10 µm	2.56	7.12	9.61	10.18	1.14%	Download
CaCO₃ — 12 µm	2.78	8.62	11.69	12.58	1.06%	Download
CaCO₃ — 15 µm	3.05	9.99	13.94	15.14	0.88%	Download
CaCO₃ — 20 µm	3.38	12.50	18.26	20.06	0.75%	Download

* All grades are available uncoated or stearic-acid coated. Coating values are measured levels determined by thermal analysis. Laser-diffraction PSD per grade; full laboratory reports on request.

Chemistry & Physical Properties

Typical properties — all grades.

Chemical analysis
Component	Typical value
CaCO₃ purity	99.9%
CaO	56.6%
MgO	0.01%
Fe₂O₃	0.001%
SiO₂	0.001%
Loss on ignition	43.89%

Physical properties
Property	Typical value
Brightness	97%
Bulk density	0.82 g/cm³
Moisture	0.02%
Appearance	White powder

Comparison of 8 and 20 µm grades
Metric	8 µm grade	20 µm grade
Volume mean D[4,3]	2.781 µm	5.193 µm
Specific surface area	1612 m²/kg	1225 m²/kg
Distribution span	2.514	3.468

Stearic acid raw material (coated series)
Property	Value
Appearance	White granules
Acid value	210 mg KOH/g
Iodine value	0.65 g I/100 g
Moisture	0.001%
Unsaponifiable matter	0.1%

Method

How we measure.

Particle size

Laser-diffraction particle size analysis on every production batch, reporting the full distribution from D3 to D98.

Brightness

Optical brightness testing on every batch — 97% typical across all grades.

Coating level

Thermal mass-loss analysis: drying at 105 °C, thermal treatment at 350 °C in a muffle furnace, exact stearic percentage from measured mass difference.

Quality system

ISO 9001:2015 certified quality management system.

FAQ

Questions engineers ask.

D50 vs D97?

D50 is the median — half the particles are finer. D97 is the top cut — 97% of particles are finer. Our grades are named by nominal top cut.

Same mineral, both series?

Yes — both series start from the same 99.9% pure ground calcium carbonate. The coated series adds measured stearic acid surface treatment.

Full lab reports?

Each grade has a downloadable TDS; complete laser-diffraction reports are available on request.

Packaging?

25 kg bags, FIBC jumbo bags, or custom packing per customer requirement.

Technical Guides

Guides to help you choose the right product.

Three short guides explaining what the numbers on this page mean in practice.

All Guides

Technical Guide

Need a value we haven't published?

Our laboratory can run the analysis your specification requires — ask us.

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