Part 1: Product Overview

Calcined Kaolin is a deeply processed product produced by sintering raw kaolin ore in a calcining furnace at 800–1000°C for a specified time, resulting in significant changes to its physical and chemical properties. Compared with uncalcined kaolin, calcined kaolin has lower bound water content, higher silicon dioxide and aluminum oxide contents, increased active sites, altered structure, and smaller, more uniform particle size.

Our calcined kaolin is made from selected high-quality raw kaolin ore using advanced ultra-fine grinding and calcination modification processes. The product features a pseudo-hexagonal porous flake crystal structure with a porosity of approximately 75%. This unique porous structure delivers excellent plasticity, adhesion, dispersibility, insulation, sinterability, flame retardancy, fire resistance, adsorbability, and weather resistance. It also features stable chemical properties, high light scattering rate, and good hiding power.

Core Value of Calcination Modification

High-temperature calcination upgrades ordinary kaolin into a high-performance functional filler, which can partially replace titanium dioxide and fully replace lithopone, greatly reducing production costs for downstream products.

Part 2: Core Advantages and Characteristics

High-Temperature Dehydration & Performance Upgrade

Calcined at 800–1000°C, the bound water content is reduced, silicon dioxide and aluminum oxide contents are increased, active sites are enhanced, and the structure is significantly modified.

Porous Flake Structure with 75% Porosity

Featuring a pseudo-hexagonal porous flake crystal structure with about 75% porosity, the product provides outstanding adsorption, hiding power, and light scattering performance.

High Whiteness & Pure Color

Whiteness ranges from 90–97%. Standard grade: 90±2%; ultra-fine grade: 93±2%; maximum whiteness exceeds 97%. It effectively improves the whiteness and gloss of coatings, paper, plastics, and other products.

Controllable Particle Size & Narrow Distribution

Full range covering 325 mesh to 6000 mesh, with fineness up to over 90% finer than 2 μm. The 3000-mesh grade is processed using advanced jet milling equipment.

Excellent Chemical Stability

Chemically stable, corrosion-resistant, fire-resistant, scrub-resistant, with good acid resistance and low cation exchange capacity.

Remarkable Reinforcement Performance

Provides significant reinforcement in rubber, improving tensile strength, tear resistance, elongation, aging resistance, and corrosion resistance. Compared with uncalcined kaolin in natural rubber (NR) compounds, low-temperature calcined kaolin shows similar curing curves, unchanged Shore A hardness, and improved tensile strength.

Flame Retardancy & Insulation

Excellent flame retardancy and electrical insulation, suitable for high-safety applications such as wires and cables.

Safe & Eco-Friendly

Non-toxic, odorless white extender pigment, classified as an environmentally friendly functional filler.

Core Indicators of Calcined Kaolin

Item	Unit	Index Range
Whiteness	%	90–97 (1250 mesh ≥92, 2500 mesh ≥92, 4000 mesh ≥93, 5000 mesh ≥93)
Refractive Index	-	1.55–1.65
Oil Absorption	g/100g	45–68 (adjustable; up to 68±5 for ultra-fine grades)
pH Value	-	6.0–7.5
Moisture	%	≤0.5–0.6
325-Mesh Residue	%	≤0.05–0.1
Porosity	%	≈75

Chemical Composition

Component	SiO₂	Al₂O₃	Fe₂O₃	TiO₂	CaO	MgO	K₂O	Na₂O
Content (%)	52±2	45±2	＜0.4	＜1.0	＜0.4	＜0.2	＜0.04	＜0.1
Typical	53.7	44.97	0.25	0.20	0.30	0.15	0.04	0.13

Note: Specific indicators are subject to the actual product test report.

Part 3: Main Application Fields

Benefiting from its porous flake structure, high whiteness, and excellent physical and chemical properties, calcined kaolin is widely used in numerous industries ranging from traditional manufacturing to high-tech sectors.

1. Coatings & Paints (Core Application)

Acts as a reinforcing filler in both solvent-based and water-based coatings, partially replacing titanium dioxide and fully replacing lithopone to directly reduce costs.

Main Functions

Improve coating hiding power and weather resistance. Enhance mechanical properties of paint films. Boost adsorbability. Provide durability, heat resistance, and opacity. Good chemical stability, corrosion, fire, and scrub resistance. High dispersibility.

Applicable Coatings

Interior & exterior wall coatings, high-grade paints, printing inks, road marking paints, latex paints, powder coatings.

2. Paper Industry

Increases coating void volume, bulk, smoothness, opacity, and flexibility of paper; improves ink absorption, gloss, and reduces printing spots.

Applications

Paper coating, paper filling.

Technical Advantages

High solids concentration (up to 74%), good dispersibility, excellent compatibility with natural/synthetic binders and additives, ideal for high-solidity coaters such as in-machine coating. Low abrasion value (only 3.6 mg/2000 cycles).

3. Rubber Industry

Used as a filler to enhance physical and chemical properties of rubber products.

Main Functions

Significant reinforcement and electrical insulation; improved tensile strength, tear resistance, elongation, aging resistance, corrosion resistance; better compatibility with rubber compounds; increased curing hardness, wear resistance, flex times, and surface smoothness.

Substitution Advantage

Can replace high abrasion carbon black, conventional carbon black, white carbon black, silica-alumina carbon black, magnesium oxide, and other expensive materials to reduce costs.

Typical Applications

Rubber soles (meeting non-transparent sports shoe sole standards), tires, rubber products, wire and cable sheaths.

4. Plastic Industry

Improves strength, whiteness, and electrical insulation of plastic products.

Main Functions

Enhance scattered light transmittance of greenhouse and agricultural films; block infrared radiation; reduce costs as a bulk filler.

Typical Applications

Greenhouse films, agricultural films, cables, PVC pipes/sheets, plastic masterbatches, engineering plastics.

5. Ceramics Industry

Ensures white, dense, smooth-surfaced ceramic products with high mechanical strength and yield.

Applications

Domestic ceramics, building ceramics, chemical corrosion-resistant ceramics, arts and crafts ceramics, sanitary ceramics, high and low voltage electric ceramics (body and glaze).

Features for Ceramic-Grade Calcined Kaolin

Produced from high-quality kaolin via tunnel kiln high-temperature calcination; high whiteness, sufficient sintering, full particles. Good thermal stability and low thermal expansion within firing range; smooth glaze with few pinholes; good flowability and dispersibility.

6. Refractory Materials

Used to manufacture various high-temperature resistant products.

Applications: Metallurgical and chemical linings, various kiln linings, high-temperature molding melting crucibles, refractory bricks, rods, sheets and special-shaped components; corundum mullite bricks, mullite low-creep bricks, mullite-cordierite kiln furniture; lightweight castables and insulation materials.

7. Glass Fiber & Precision Casting

Glass Fiber Grade Calcined Kaolin

• Produced from high-quality coal-series kaolin via calcination and decarbonization.

• Low COD, higher aluminum content than traditional water-washed kaolin.

• Multi-stage homogenization ensures stable chemical composition.

• Precise classification meets customer fineness requirements.

Precision Casting Mullite Sand/Powder

• Made from high-quality coal-series kaolin via high-temperature calcination.

• High mullite content, low iron, high and uniform whiteness.

• High refractoriness, good thermal shock resistance, low thermal expansion.

• Low water absorption, good collapsibility.

8. Catalysts & Petrochemical Industry

Petroleum Catalysts

Coal gangue calcined into white kaolin powder, processed through pulping, grinding, gelling, etc., can be used as FCC catalyst precursors, improving refining efficiency, reducing emissions, and enhancing performance for refineries.

Catalyst Carrier

Used in oil refining to improve oil quality.

9. Pesticides & Feed

With fine surface pores and strong adsorbability, it is used in medicine and pesticides.

Applications: Pesticide carriers, feed additives, silicon fertilizer raw materials (neutral, high silicon content).

10. Cosmetics & Daily Chemicals

Used as a white extender pigment in cosmetics.

Applications

Facial masks, powder cakes, toothpaste, high-grade daily chemicals.

Substitution Advantage

Can replace titanium dioxide to reduce costs.

Part 4: Product Specifications & Technical Parameters

Product Series

Product Grade	Mesh Size	Whiteness	Median Particle Size	Main Features	Main Applications
General Grade	325, 400, 600, 800	90±2%	10–45 μm	Economical, basic filler	Building materials, basic raw materials
Ultra-Fine Grade	1250, 2000	≥92%	5–10 μm	High whiteness, good dispersibility	Coatings, rubber, ceramics, binders
Fine Grade	2500, 3000, 4000	92–93%	3–5 μm	Moderate oil absorption, good hiding power	High-grade coatings, inks, plastics
Superfine Grade	5000, 6000	≥93%	1–2 μm	Fine particle, high activity, oil absorption 65±5	Engineering plastics, high-grade inks, fine chemicals
Ceramic Grade	1250–6000	≥92%	Customized	Good thermal stability, smooth glaze	High-grade ceramics, glazes
Refractory Grade	325, 800	≥90%	Customized	High refractoriness, good thermal shock resistance	Mullite, castables, refractory kiln furniture

Technical Parameters

Grade	Whiteness (%)	pH Value	Refractive Index	Oil Absorption (g/100g)	Moisture (%)	325-Mesh Residue (%)
1250 (10μm)	≥92	6.0–7.0	1.62	45	≤0.5	＜0.5
2500 (5μm)	≥92	6.0–7.0	1.62	50	≤0.5	＜0.5
4000 (3μm)	≥93	6.0–7.0	1.62	55	≤0.5	0
5000 (2μm)	≥93	6.0–7.0	1.62	65	≤0.5	0
6000 (1μm)	≥93	6.0–7.0	1.62	65	≤0.5	0