Calcined Kaolin-Performance enhancing specialty mineral

During the process of calcination, morphological, mineralogical and chemical changes occur resulting in the products with superior optical properties. Calcined clay (Calcined Kaolin) is its best example and the opacifying property makes it a universal choice for water based paints. Calcined clay functions as a synthetic pigment that gives color to the paints. Other synthetic pigments can be engineered molecules, blanc fixe, precipitated calcium carbonate and synthetic pyrogenic silica while natural pigments are clay, calcium carbonate, mica, silica, and talc.

Clay / Kaolin beneficiation process

Before using Kaolin, it is necessary to convert it into Kaolin powder with the help of mining equipments such as crushers, grinding machines etc. This process is termed as Kaolin beneficiation. Depending on the combustion temperatures, the properties and applications of calcined kaolin differs.

Marvels of MetaKaolin

To raise the material to high temperature (calcination) in a continuous process, a pyroprocessing device is used called rotatory kiln. And metakaolin is a scientifically processed reactive aluminosilicate pozzolan formed by calcining purified clay in an externally fired rotary kiln.

Calcined Kaolin finds diverse applications across industry sectors because of its properties such as color, softness, viscosity and small particle size. It is extensively used n fertilizers, detergents, textiles, cosmetics, insecticides, medicines and cement industry. Silica Fume has been used for many years in the areas where high strength and durable concrete were required. Silica Fume, one of the widely used mineral admixtures enhances the characteristics of both fresh and hard concrete.

In addition to above, Calcined Kaolin is also used in coating materials, functional fillers, extenders, pigments and porcelain applications.

Versatile Calcined Kaolin finds applications across Industrial Sectors

A fine blend of unique physical and chemical properties makes Kaolin, also called as Kaolinite, a key product in multiple industrial sectors. The shape, particle size, whiteness, softness, chemically inert nature and non-abrasiveness of kaolin holds critical value as an industrial mineral with wide applications in paper, rubber, paint, ceramics, plastics, ink, catalysis, insecticides and in many other segments.

Named after the famous 'Kao-ling' hill in China, Kaolin (Kaolinite, China Clay) is a group clay minerals belonging to sheet silicates with the general formula Al₄[Si₄O₁₀](OH)₈

Calcined Kaolin (Calcined Clay):

Calcined kaolin is a commercial grade of kaolin which is synthesized by calcination process. The process of producing calcined kaolin from kaolin is carried out in either conventional calcination method or flash calcination techniques. Calcined kaolin, or popularly referred as calcined clay, is an anhydrous aluminium silicate with enhanced whiteness, hardness, electrical properties and kaolin particle structure.

Metakaolin:

Metakaolin is refined kaolin clay produced by dehydoxylation of kaolin above 700^oC. Extensive researches on metakaolin have revealed that it is complex amorphous structure of silica SiO₂ and alumina Al₂O₃.

Silica Fume (Micro Silica):

Silica fume, often confused with fumed silica, are primarily composed of non-crystalline SiO₂ particles. It is produced as byproduct during the production of elemental silicon or alloys containing silicon.

Industrial Applications of Calcined Kaolin:

Calcined kaolin finds multiple applications across industries because of its color, softness, viscosity and small particle size. It is extensively used in coating materials, functional fillers, extenders, pigments and porcelain applications. In plastic industry, it is used in PVC cable to enhance electrical performance.

Paper Industry

Significant amount of calcined kaolin is used in Paper industry as a coating pigment and fillers. Its favorable optical properties and chemically inert nature is particularly suited for applications in paper industry. The relationship between the particle size and opacity of calcined kaolin holds immense value in paper industry. It is a cost-effective solution with its unique properties like coat weight, smoothness and texture.

Rubber Industry

Calcined kaolin is used as a functional filler in natural and synthetic rubber products as it lends strength, resistance against abrasion and rigidity. With low cost, whiteness and excellent functional features, it is one of the most widely used filler in rubber industry.

Paint Industry

Calcined kaolin finds usage in the extender pigments since decades. It is used as partial replacement of TiO₂ and helps in maintaining proper dispersion because of its rheological properties. Calcined kaolin is inexpensive and gives desired flow to the paint solutions.

Ceramic Industry

Dielectric properties and chemical inertness makes calcined kaolin favorable in ceramic and porcelain electrical insulators. In refractories, it finds applications because of its exceptional dimensional stability, high fusion point and minimal water content.

Plastic Industry

Being chemically inert and well-suited particle size and structure, calcined kaolin is used as functional fillers in plastic industry. It gives perfect smoothness, finishing, chemical resistance and structural stability to the plastic products.

In addition to above, calcined kaolin is also used in cement, fertilizers, detergents, textiles, cosmetics, insecticides and medicines.