Calcium Carbonate Knowledge Hub
10 Micron Calcium Carbonate
2026-09-04 16:44:39
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10 micron calcium carbonate is a fine ground calcium carbonate (GCC) grade whose particle-size target is commonly expressed as a D50 of about 10 µm, although some suppliers use “10 micron” as a broader commercial grade name. It is widely used in PVC, masterbatch, plastics, paint, rubber, sealants, adhesives, and selected paper or construction products where a smoother filler and lower coarse residue are needed than with 20–25 µm grades.
The phrase must be qualified by the full particle-size distribution. A powder with D50 = 10 µm can still have a D97 or D98 near 45 µm, which may be acceptable for one use but unsuitable for a high-gloss coating, thin film, or premium cable compound. One commercial GCC grade, for example, is specified as D50 10 µm and D98 45 µm.
What Does 10 Micron Mean?
Ten microns equals 0.010 mm. At this fineness, calcium carbonate is typically measured by laser diffraction rather than conventional sieve analysis. The term may refer to the median particle size, maximum particle size, or a nominal supplier grade, so the definition must be stated in the product specification.
| Possible meaning | What it tells you | What it does not tell you |
|---|---|---|
| D50 = 10 µm | Half of the measured particle volume is finer than 10 µm | The size of the coarse tail or the finest fraction |
| D97 = 10 µm | 97% of the particle volume is below 10 µm | Whether the product has the desired median size, surface area, or coating quality |
| Maximum particle size ≤10 µm | Top-size control, if accurately measured | The distribution below 10 µm |
| “10 micron” commercial grade | General fine GCC category | A standardized PSD or direct comparability between suppliers |
For purchasing, the strongest approach is to specify D10, D50, D90, and D97 or D98, together with the laser-diffraction method and sample-dispersion procedure.
10 Micron vs Other Grades
| Size reference | Relative fineness | Typical use direction |
|---|---|---|
| 38 µm | Fine sieve-grade powder | Putty, rubber, artificial stone, tiles, selected plastics |
| 25 µm | Fine filler | Paints, rubber, sealants, adhesives, construction chemicals, selected PVC |
| 20 µm | Fine GCC | Paints, PVC, general plastics, rubber, sealants, wall coatings |
| 10 µm | Very fine GCC | PVC, masterbatch, plastics, paints, rubber, sealants, adhesives, paper-related products |
| 2–5 µm | Ultrafine GCC | High-quality coatings, premium PVC, fine masterbatch, paper coating, specialty fillers |
| Below 1 µm | Very fine PCC or nano-oriented material | Specialty coatings, functional fillers, high-performance polymer systems |
Moving from 20 µm to 10 µm increases surface area and can improve smoothness, packing, and filler distribution. It can also raise oil absorption, compound viscosity, coating-agent demand, powder cohesion, and manufacturing cost. The best choice depends on the required final properties, not simply on the smaller micron number.
How 10 Micron GCC Is Produced
10 micron calcium carbonate is produced from high-quality limestone, marble, chalk, or calcite. The material is crushed, dried if needed, finely ground, and classified in a closed circuit so oversized particles return to the mill.
Calcite-rich carbonate feed → crushing → moisture control → fine grinding → high-efficiency air classification → powder collection → optional surface treatment → cooling and deagglomeration → quality testing → packing or bulk delivery
Ball mills with air classifiers, vertical roller mills, ring roller mills, and other fine-grinding systems can be used. The classifier is essential: it controls the D50, upper particle-size limit, and product yield. Without stable classification, a powder may have an acceptable average size but still contain too many coarse particles for the intended application.
Production controls
Raw-material purity: High CaCO3, low MgO, low silica, low iron, and high whiteness are important for fine GCC.
Moisture: Low, stable moisture avoids mill buildup, classifier instability, agglomeration, and poor powder flow.
Grinding: Feed rate, mill energy, airflow, temperature, and internal wear affect the final size distribution.
Classification: D90, D97, or D98 must be monitored to control the coarse fraction.
Contamination: Magnets, clean conveying, and suitable wear materials reduce iron, grit, and dark specks.
Storage: Fine powder should be cooled and protected from moisture to preserve flowability and prevent caking.
Coated vs Uncoated 10 Micron Calcium Carbonate
10 micron calcium carbonate is available as uncoated GCC or stearic-acid-coated GCC. The choice depends mainly on the formulation’s binder system.
| Type | Typical applications | Why it is selected |
|---|---|---|
| Uncoated 10 micron GCC | Water-based paints, paper-related uses, wall coatings, construction products, selected rubber formulations | Natural calcium carbonate surface can suit aqueous and mineral-based systems |
| Stearic-acid-coated 10 micron GCC | PVC, PE, PP, masterbatch, cable compounds, rubber, sealants, adhesives | Hydrophobic surface can improve compatibility, dispersion, and moisture resistance in non-polar polymer systems |
Coating performance becomes more important as the powder becomes finer because specific surface area increases. Treatment level should be optimized using actual surface area, activation rate, moisture, resin type, filler loading, and compound trials. A fixed dosage suitable for a 25 µm grade may not be suitable for 10 µm GCC.
Common Applications
| Application | Role of 10 micron calcium carbonate | Key selection controls |
|---|---|---|
| Rigid PVC pipe and profile | Fine filler, often coated, for selected formulations requiring good dispersion and surface quality | D50, D97, whiteness, moisture, coating quality, extrusion performance |
| PE and PP masterbatch | Fine mineral filler used to manage cost and compound properties | Fine PSD, hydrophobicity, surface area, bulk density, low moisture, melt-flow behavior |
| Wire and cable compounds | Fine filler for controlled distribution in polymer matrices | Low moisture, coating condition, PSD, electrical and mechanical formulation requirements |
| Paints and coatings | Fine extender filler influencing film smoothness, viscosity, coverage, and cost | Whiteness, low grit, PSD, oil absorption, dispersion, gloss, binder compatibility |
| Rubber | Fine filler for compound processing and property adjustment | Particle size, moisture, coating, surface area, dispersion, cure compatibility |
| Sealants and adhesives | Fine filler affecting rheology, density, extrusion, and formulation economy | PSD, oil absorption, moisture, coating, flowability, storage stability |
| Paper and paperboard | Potential filler or coating component in qualified systems | Brightness, low grit, fine PSD, slurry behavior, retention, and optical properties |
Commercial 10 micron calcium carbonate products are marketed for masterbatch, plastic molding, PVC cable, paint, PVC pipe, rubber, and paper-related uses, often with high whiteness and low moisture requirements. Actual performance must be validated in the customer’s formulation.
How to Specify a 10 Micron Grade
A purchase order should state whether 10 µm refers to D50, D97, D98, or another measurement. This avoids receiving a powder with the right nominal label but an unsuitable coarse tail or surface area.
| Specification item | Why it matters |
|---|---|
| 10 µm definition | Clarifies whether it refers to median size, top cut, D97, or maximum particle size |
| D10, D50, D90, D97, and D98 | Defines the complete PSD and coarse fraction |
| Laser-diffraction method and dispersion protocol | Ensures supplier and customer results are comparable |
| Specific surface area | Helps predict coating demand, oil absorption, viscosity, and resin interaction |
| CaCO3, CaO, MgO, SiO2, Fe2O3 | Confirms purity, whiteness potential, and abrasive-impurity control |
| Acid-insoluble residue | Controls non-carbonate grit and contamination |
| Whiteness, brightness, and Lab* values | Important for white PVC, paint, coatings, paper, masterbatch, and sealants |
| Moisture, bulk density, and flowability | Affect storage, bagging, silo discharge, dosing, and compounding |
| Coating condition and activation rate | Required for polymer-grade stearic-acid-coated GCC |
| Application trial data | Confirms real performance in the intended PVC, masterbatch, coating, rubber, adhesive, or sealant system |
Key Takeaway
10 micron calcium carbonate is a very fine GCC grade often specified with D50 around 10 µm. It is used in PVC, masterbatch, plastics, cable compounds, paints, rubber, sealants, adhesives, and selected paper applications where smoother filler dispersion and lower coarse residue are required.
Do not buy the grade based only on “10 micron.” Confirm whether this refers to D50 or another limit, then review D97 or D98, purity, whiteness, moisture, surface treatment, and end-use test results. These parameters determine whether the calcium carbonate will provide the desired processing stability, surface finish, rheology, and cost-performance balance.
