Kaolin (China Clay)
High-Purity Industrial Grade Kaolin – Reliable Bulk Supplier for Coatings, Ceramics, Polymers, Paper, Rubber, and Specialty Chemical Manufacturing
Kaolin (China Clay) is a refined hydrated aluminum silicate mineral widely used as a functional industrial raw material, filler, coating pigment, and rheology modifier. It is valued for its controlled particle size distribution, high brightness, low abrasiveness, chemical inertness, and stable dielectric properties. Industrial buyers source kaolin for applications requiring consistent mineralogy, whiteness, dispersion stability, and predictable performance in formulations and manufacturing processes.
Natraj Chem supplies industrial-grade kaolin sourced from validated producers and processed to meet strict physical and chemical specifications suitable for coatings, ceramics, polymers, paper, rubber, refractories, and specialty chemical manufacturing.
Chemical Identity
| Parameter | Specification |
|---|---|
| Chemical Name | Hydrated Aluminum Silicate |
| Mineral Type | Kaolinite Clay |
| Chemical Formula | Al₂Si₂O₅(OH)₄ |
| CAS Number | 1332-58-7 |
| HS Code | 2507 |
| Appearance | Fine white to off-white powder |
| Odor | Odorless |
| Solubility | Insoluble in water |
| Crystal System | Triclinic |
Technical Properties
Precise physical and chemical characteristics engineered for consistent industrial performance.
| Property | Typical Range |
|---|---|
| Brightness (ISO) | 80 – 92% |
| Moisture | ≤ 1.5% |
| pH (10% slurry) | 4.5 – 7.0 |
| Oil Absorption | 35 – 55 g/100 g |
| Bulk Density | 0.30 – 0.60 g/cm³ |
| Specific Gravity | 2.58 – 2.63 |
| Particle Size (D50) | 0.5 – 5 µm |
| Residue on 325 mesh | ≤ 0.5% |
| Hardness (Mohs) | 2 – 2.5 |
| Refractive Index | ~1.56 |
Values vary depending on grade and processing method (washed, calcined, micronized, or surface-treated).
Key Functional Benefits
Eight performance properties that make kaolin the preferred industrial mineral across global manufacturing
Chemically Inert Filler
Compatible with acids, salts, and organic systems — ensuring broad formulation versatility across industrial, rubber, and pharmaceutical processing environments without reactive side-effects.
Opacity & Gloss Control
Enhances opacity, gloss, and smoothness in coatings while reducing costly TiO₂ loading.
Dimensional Stability
Reliable shrinkage control during ceramic firing and drying for consistent finished dimensions.
Electrical Insulation
High dielectric strength — essential for cable compounds, electronics, and engineering plastics.
Anti-Caking & Flow
Reduces agglomeration and improves flowability for automated dosing and conveying lines.
Low Abrasiveness
Mohs 2–2.5 protects equipment blades and extruder screws from accelerated wear.
Barrier Properties in Films
Plate-like particle morphology creates a tortuous diffusion path that significantly improves moisture and gas barrier performance in films, coatings, and flexible packaging applications.
High Dielectric Strength
Supports electrical and electronic insulation formulations requiring stable dielectric performance at elevated operating temperatures — a critical differentiator in high-voltage cable and electronic component manufacturing.
Industrial Applications
Hover over any industry card to reveal kaolin's specific role in that sector
Paints & Coatings
Extender pigment controlling sheen, suspension, and film integrity while optimising TiO₂ usage and brushability.
Paper & Pulp
Coating pigment and filler improving printability, brightness, ink receptivity, and sheet smoothness.
Ceramics & Refractories
Plasticity, thermal resistance, and shape retention in sanitaryware, tiles, porcelain, and kiln furniture.
Plastics & Polymers
Enhances stiffness, electrical insulation, and dimensional stability in PVC, PE, PP and engineering plastics.
Rubber Industry
Reinforcing filler improving tensile strength, abrasion resistance, and extrusion in natural and synthetic rubber.
Construction Materials
Mineral additive in cement, sealants, joint compounds, and white mortars improving rheology and crack resistance.
Pharma & Cosmetics
Excipient, absorbent, and mattifying base material with controlled purity and microbiological limits.
Agrochemicals
Carrier mineral for pesticides and fertilizers ensuring uniform dispersion, controlled release, and crop protection.
Grades / Specifications Available
Each grade is engineered for a specific performance profile — matched to your industry, process conditions, and regulatory requirements
Washed Kaolin
Beneficiated and water-processed to remove impurities — consistent brightness and purity for coatings, paper, and high-quality polymer formulations.
Calcined Kaolin
Heat-treated for superior brightness, opacity, and porosity — ideal for high-performance coatings, plastics, and rubber requiring enhanced optical and barrier properties.
Hydrous Kaolin
Retains natural crystalline structure for plasticity and suspension applications — preferred for ceramics and rubber requiring controlled rheology.
Micronized Kaolin
Ultra-fine particle size distribution for demanding applications requiring maximum surface area, superior opacity, and smooth finish in films and coatings.
Pharma / Cosmetic Grade
Controlled impurity profile with strict microbiological limits — meets pharmacopeial standards for excipient, absorbent, or cosmetic base material use.
Custom / Surface-Treated
Surface-modified or tailored PSD, brightness, and moisture specs for OEM requirements, rubber reinforcement, and specialty formulation needs.
💡 Custom particle size distribution and brightness ranges can be supplied based on formulation requirements.
Our technical team provides expert consultation on grade selection based on your specific application requirements, processing conditions, and regulatory compliance needs. Contact us to discuss your formulation challenges and receive customised solutions.
Quality Control Parameters
Every lot passes through a structured audit protocol before release — no exceptions
QC Audit Parameters
Eight mandatory tests conducted on every incoming and outgoing batch — results documented and traceable
Mineralogical Composition (XRD)
X-ray diffraction confirms kaolinite composition and rules out contaminating mineral phases.
Particle Size Distribution (Laser Diffraction)
D10, D50, and D90 measurements for consistent downstream formulation performance.
Brightness and Whiteness Index
ISO brightness and whiteness index verified for colour consistency across supply batches.
Loss on Ignition (LOI)
Thermal analysis confirming mineral purity and absence of organic contaminants.
Iron and Titanium Content
Elemental analysis critical for meeting brightness specifications in paper coating and high-brightness grades.
Moisture Content & Residue / Grit Level
Controlled moisture and grit testing ensures processing performance and prevents equipment fouling.
pH Stability
Verified pH in 10% slurry for reliable formulation performance across water-based and solvent-based systems.
Heavy Metals Screening (When Required)
Comprehensive testing to meet pharmaceutical, cosmetic, and food-grade regulatory requirements on request.
Material is released only after full conformity to specification sheets and COA validation. Batch certificates ensure traceable consistency across all supply cycles.
Packaging & Supply
Four packaging formats designed for safe handling, moisture protection, and logistics efficiency at every scale
Multiwall Paper Bags with Liner
Laminated paper with inner PE liner for moisture protection and powder containment.
HDPE Woven Bags
Heavy-duty woven poly construction with heat-sealed top for secure bulk industrial use.
FIBC Jumbo Bags
4-loop flexible bulk container for crane or forklift handling of high-volume requirements.
Bulk Tanker Supply
For high-volume industrial requirements — palletised, moisture-protected delivery direct to site.
Material is palletised, moisture-protected, and labelled for industrial inventory systems. Supply maintained through multi-source procurement and inventory coordination.
Storage & Handling
Follow these guidelines to maintain optimal product quality and ensure workplace safety
Dry, Ventilated Conditions
Store away from moisture and volatile chemicals in well-ventilated areas. Maintain relative humidity below 60% to preserve flowability, brightness, and particle integrity.
Sealed Packaging Integrity
Maintain original packaging seal until point of use. Reseal partially used bags immediately to prevent moisture uptake, contamination, and uncontrolled particle agglomeration.
Dust Extraction During Handling
Use enclosed transfer conveyors or local exhaust ventilation systems when handling fine grades. Minimise dust formation to comply with occupational exposure limits for nuisance dust.
Indefinite Shelf Life
Kaolin is stable and non-reactive. Shelf life is effectively indefinite when stored dry and sealed — no degradation of mineral properties, brightness, or particle size distribution over time.
Regulatory / Safety Information
Kaolin is a non-hazardous mineral under standard transport and industrial classifications when handled in accordance with occupational safety guidelines.
Meets industrial mineral purity standards. Users must follow local occupational exposure and dust control regulations.
Why Industries Source from Natraj Chem
- Established chemical supply expertise since 1984
- Technical evaluation of manufacturers before sourcing
- Multi-industry specification matching
- Reliable contract supply capability
- Batch-to-batch consistency assurance
- Documentation-ready materials for regulated industries
- Strong vendor validation and quality audit process
The sourcing model ensures consistent quality without production variability risks.
Technical Support & Documentation
Industrial buyers receive comprehensive documentation and hands-on technical assistance from our specification-experienced team
Certificate of Analysis
Batch-specific quality verification with full test results and compliance confirmation for every supplied lot — traceable and audit-ready.
Technical Data Sheet
Detailed grade specifications and performance characteristics for technical evaluation, formulation design, and supplier approval.
Safety Data Sheet
GHS-format hazard information and safe handling guidelines for workplace safety, regulatory compliance, and customs documentation.
Particle Size Distribution Report
Laser diffraction PSD report with D10, D50, D90 data to verify grade suitability for your specific processing and application needs.
Application Guidance
Formulation compatibility guidance covering viscosity, opacity, mechanical properties, and thermal performance across key industrial sectors.
Pre-Shipment Sample Evaluation
Grade samples available for technical validation and formulation trials before bulk procurement commitment is made.
Frequently Asked Questions
Industrial kaolin is used as filler, coating pigment, rheology modifier, and reinforcement mineral in coatings, plastics, ceramics, paper, and rubber manufacturing.
No. Kaolin is chemically inert under most processing conditions, making it compatible with acids, salts, and polymers.
Fine particle grades with D50 below 2 µm provide better opacity, smoothness, and gloss control in coating formulations.
Calcined kaolin is heat-treated for improved brightness and opacity, while hydrous kaolin retains its natural crystalline structure for plasticity and suspension applications.
Yes. Its plate-like particles enhance stiffness, dimensional stability, and barrier performance in polymer matrices.
Pharma grades require controlled heavy metals, low microbial count, and strict mineral composition limits as per pharmacopeial standards.
It improves suspension, reduces settling, controls gloss, and optimises pigment cost efficiency while maintaining film integrity.
Yes. Kaolin remains stable at elevated temperatures and converts to metakaolin upon calcination, making it suitable for refractory applications.
High-quality coating grades typically range from 88% to 92% ISO brightness.
Yes. Particle size, brightness, moisture, and surface treatment can be tailored to application requirements for OEM and specialised formulation needs.
Get Technical Data & Custom Quote Today
Ready for high-purity grades, industrial-scale volumes, or tailored specifications? Our team provides fast responses with full documentation — no obligation.
- Technical datasheets (TDS) & Safety Data Sheets (SDS)
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