Rocks that are rich in kaolinite are known as Kaoling, kaolin, Kalaba or china clay. China Clay falls under Kaolinite group of clays. It has the usual compositions of Al2O3, 2SiO2, 2H2O, Hydrous Aluminium Silicate. China Clay mining is a complicated process which can be split into three distinct sections opencast mining, refining and drying. China Clay occurs in the deposits of rock china clay, a mixture of up to 15 percent China Clay, and up to 10 per cent mica, and the remainder being quartz. The clay itself varies considerably from pit to pit. In some deposits, the clay is ideally suited for the filling and coating of paper, while in other deposits,other gradess China clay suits best. China clay has a low shrink-swell capacity and a low cation exchange capacity (1-15 meq/100g). It is a soft, earthy, usually white mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminium silicate minerals like feldspar. China clay is available in the form of lumps and powder (Pure white colour, off white colour and calcined powder).
· Low shrink swell capacity at 1300C is about 12%
· Lowcation exchange capacity (1-15 meq/100g
· High luster, opacity, gloss
· High mechanical strength
· Dimensionally stable
· Improved electrical properties
· High extrusion properties
· Anti cracking
Paints :- It is used in various paints like distempers, cement primer, wood primer, texture paint, spray plaster, putties, fillers undercoats.
· China clay due to its lamellar structure imparts toughness to coatings and tends to reinforce the films.
· It settles slowly in water and having low solubility in water, it is commonly used in water based paints.
· Due to its low solubility in the aqueous phase and its ability to impart good brushing and leveling characteristics, it is mainly used in latex paints.
In adhesives sealants, china clay gives good barrier effects and rheology control. The controlling rheology influences the speed at which adhesive can be applied which is important in high speed paper laminating processes. The low surface hydroxyl content of calcined China clay leads to a low moisture pick-up, resulting in excellent performance in moisture sensitive sealant applications. Calcined clay is also effective as structure building components.
It is used as a filler in combination with others to impart strength smoothness in plastic Industry for PE master batch; PE cables; PE film; PVC cables; PVC extrusions; PVC plastisols; PP moldings; polyamide moldings; PBT/PET moldings; unsaturated polyester; urea formaldehyde; phenol formaldehyde.
China Clay is also called KAOLINE, it is one of the essential Raw materials for ceramic Industries. China Clay does not swell on adding water Alumina present in Clay do not form
Isomorphous series with any other metallic compound. It is naturally hydrated Aluminum Silicate and is one of the most abundantly available clay in the Earth's crust. China Clay is the heart of potteries, tiles, ceramics, Glazes and many other industries.
The China Clay can be effectively used in manufacturing of fiber glass because of its high alumina content.
It is used in variety of papers, cardboards, hard boards and others.
Grit free china clay having low bulk density, possessing reinforcing properties, is used as filler and to improve tensile, flexural modules make a significant increase.
It is used for Electrical insulation, High voltage insulation components, electrical wires, EPDN rubber and others.
China Clay is used in toothpaste, cosmetics and soap industry.
China clay is used in white cement, Refractory bricks and in port, it acts as fog removing agent, dust collecting agent on road and fireproof agent of textile.