Calcined Kaolin And Calcined China Clay

Product Details:
  • Packaging Type: Packet, Drum/Barrel, Bottle, Box
  • State: Powdered, Liquid, Solid, Crystal

Kaolin Clay is a Platy Alumino Silicate. Its continuous Sheet Structure produces thin Particles which exist in nature as overlapping flakes. These can occur as “Books” which inder magnification resembling stacks of paper. Kaolin Crystals are bound via hydrogen bonding of the Octahedral layer hydroxyl face of one plate to the tetrahedral layer oxygen face of adjacent plate. Separation into individual clay plates is therefore difficult, but can be accomplished by mechanical means to produce delaminated kaolin.

The Effects of Fillers Depend upon:
  • Particle Size
  • Particle Surface Area
  • Particle Shape
  • Particle Surface Activity (Compatability with adhesion to Matrix)
Surface Activity relates to the compatabilty of the filler with a specific elastomer and the ability of the elastomer to adhere to filler.

Functional Fillers transfer applied stress from the rubber matrix to the strong and stiff mineral. It seems that this stress transfer will be better effected if the mineral particles are smaller because greater surface is thereby exposed for a given mineral concentration. If these particles are needle like, fibrous or Platy in shape , they will better intercept the stress propagation through the matrix.

A compound’s physical/mechanical properties can be strongly influenced by the surface activity of the filler, which is the ability of the filler’s surface to bond with the matrix. For instance, an air gap between a filler particle size and the matrix represents a point of zero strength.

If the size of the filler particle greatly exceeds the polymer interchain distance, it introduces an area of localized stress. This can contribute to elastomer chain rupture on flexing or stretching.

Fillers with particle size greater than 10,000nm (10mcrons) are therefore generally avoided because they can reduce performance rather than extend or reinforce.

Fillers with Particle Size between 1000 to 10000nm (1 to 10microns) are primarily used as Diluents and usually have no significant effect, positive or negative on Rubber Properties.

Semi- reinforcing fillers ranging from 100 to 1000nm (0.1 to 1microns).

The Truly reinforcing fillers which range from 10nm to 100nm (0.01 to 1 micron) can significantly improve rubber properties.
Application of Kaolin Clays in Rubber

Hard Clays :

Particle Size : 0.25 -0.5 Microns
  • Very Fine grained
  • Provides good Tensile Properties
  • Stiffnesss
  • Abrasion Resistance
  • Improves Properties of Ground Calcium Carbonate Compounds
  • Low Cost Substitute for Portion of Carbon Black/PPT Silica

Soft Clays:

Particle Size : 1 – 2microns
  • Larger Flakes
  • Low Reinforcing Effect
  • Higher Loadings
  • Quicker Extrusions


Product Details:
  • Packaging Type: Packet, Drum/Barrel, Bottle, Box
  • State: Powdered, Liquid, Solid, Crystal

Kaolin clay available as lumps, noodles and powder

Whitness: 85-95
Brightness 81-88

For ceramics, paints, and paper applications

Calcined Kaolin

Product Details:
  • Packaging Type: Packet, Drum/Barrel, Bottle, Box
  • State: Powdered, Liquid, Solid, Crystal

Zigma processes aluminum silicate clay mineral - Kaolinite used by the coatings industry. Superior Kaolin grades from exclusive mines is water washed to remove mineral impurities then bleached,classified and calcined at higher degree of temperature to attain bright white pigmentation properties.

Zigma Calcined Kaolin are offered in more varieties than other silicate functional fillers in order to provide a range of particle crystallinity and shapes, controlled particle size fractions,brightness and opacity.

These grades are made even more versatile through chemical modification available with dispersant coatings for easy dispersion in water, as well as stearate or silane surface treatment for improved compatibility with organic matrices.
Rubber Industry uses various fillers at each step from rubber vulcanization to color, reinforce, extend, and to reduce the cost of compounds.

The primary use of brighter Kaolin in coatings is as a titanium-di-oxide extender in water-borne architectural paints. Calcined Kaolin clays generally provide the best brightness, titanium dioxide extension and dry hide. Water washed and processed grades contribute to extension and dry hide, as well as covering power and gloss control.

  • Water based decorative paints
  • Gloss, semi-gloss and silk; exterior coatings
  • Matt - smooth and textured
  • Exteriors Primers for interiors
  • Solvent based decorative paints
  • Protective and OEM coatings
  • Metal primers
  • Furniture lacquers
  • Domestic appliance finishes
  • Electrophoresis coatings
  • Coil coatings
  • Traffic marking paints
  • Printing inks
  • Other Uses: Plastics, Ceramics, Refractory, Construction,Paper Coating, etc.

Hydrous Kaolin

Product Details:
  • State: Powdered, Solid

Zigma offers two grades of hydrous washed kaolin mined in Bhuj, Gujarat. The crude kaolin is washed to remove grit and other impurities. Various proprietary chemical processes are also used to purify the clay further. It is further filter pressed to form kaolin cakes that are sun dried and broken into lumps. The washing and removal of impurities enhances the whiteness of kaolin which makes it very valuable for the ceramic industry.

Washed kaolin lumps can further be pulverized and/or classified for applications in rubber, plastic, paper, and paint industries.

Ceramic Grades :

  • Britonz HB (Whiteness L* 91)
  • Opax HB (Whiteness L*93)

Paper Grades :
Zigma offers three grades of kaolin for the paper industry. These clays are available as lumps, powder, and slurries. Zigma is the only producer of Kaolin slurries in India at 65% solids.

% Particle <2µmISO Brightness

Rubber Kaolin :
Zigma offers washed kaolin powders with minimal grit content and for the rubber industry. The rubber kaolin can be processed to a variety of particle sizes, colour, and grit content as desired by the customer.

Agricultural Kaolin :
Kaolin with different particle sizes and densities can be used for sprayable and granulated pesticide/herbicide formulations. These kaolin offer high reflectance, sprayability, and stability to agricultural applications.

Kaolin For Paper

Product Details:
  • State: Powdered

Background :

Various grades of kaolin are produced to enable end-users to produce a specific level of performance in their products. Typically the major features a papermaker is seeking in order to keep his clients coming back and a pigment supplier can influence is:

  • Sheet of paper looks good (colour, brightness, smoothness, opacity)
  • Sheet of paper prints well (ink absorption and ink pigment holdout, low linting tendency, roughness)

To obtain these often-contradictory properties it is necessary to blend kaolins with other pigments like calcium carbonate, talc, titanium dioxide, satin white, etc.

Therefore performance in the sheet is the important criteria for kaolin although it can be difficult to introduce a product, which may have unusual pigment properties particularly if those properties are regarded as impacting on processing efficiencies. The growth in alkaline sizing and use of GCC PCC including in-house and satellite plants may affect kaolin volumes in the years ahead.

Kaolin Types
Kaolin is produced from ore-bodies with inherent and largely unalterable properties. The process plant seeks to manufacture grades of kaolin, which consumer expectations (table 1). Generally an ore-body will limit the range of products that can be economically produced. As a consequence, European consumers have a history of using coarse English clays whilst Asian consumers and US have been helped by a wide range of high brightness Georgian kaolin that can range from ultrafine particle size to coarser delaminated kaolins. The Asian market uses a simple classification system based on brightness and, to a lesser extent, particle size. The system was based originally on conventional water-washed grades of kaolin.Calcined kaolins and delaminated kaolins are viewed as specialty kaolins and filler kaolins are a separate segment altogether.
Typical paper kaolin grades.

Filler grades

Key Characteristics : Brightness Particle size distribution
This is a low cost grade competing with carbonate and talc. The market is dominated by variable quality product from Indonesia. A high brightness, low cost kaolin with good brightness could appeal to Japanese papermills.

Key Characteristics : Brightness ,Aspect ratio, surface area and to a lesser extent particle size distribution
Delaminated kaolins not widely used in Asia currently, however, good growth prospects as this product is used in the fastest growing segment, lightly coated paper. Trend is to use No 2 grade kaolin. Brazilian producers have developed high brightness, low viscosity products in this sector and are making inroads.

Key Characteristics: Brightness,Opacifying power
Highest value clay due to high energy (calciner) required in production, low bulk and consequently high shipping costs. The market for calcined continues to grow as whiteness standards are driven ever higher by competitive pressures including use in newsprint grades.
No 1 Coating

Key Characteristics :Brightness ,Particle size distribution,Viscosity
High brightness is the key feature and is typically >90 %GE with recent developments raising limits to 91% GE. Particle size distribution can be quite fine (98%<2µm) to coarse (85%<2µm) although the mid range and fine grades are dominant.
No 2 Coating

Key Characteristics: Medium brightness,Particle size distribution,Viscosity
The brightness range is 2-3 points below No 1 grades. The dominant grades are at the coarse end and the fine end. Some overlap with delaminated grades has occurred with the coarser grades.
Kaolin - Processing and Manufacturing
The processing of kaolin varies greatly from company to company;
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