China clay

Listing ID #367189

We are offering china clay.
china clay
china clay, also called kaolin, falls under kaolinite group of clay minerals. It results from the alterations of feldspars, granite, gneiss and pegmatite rocks by hydrothermal action of aqueous solution. China clay usually carries some impurities in a small quantity such as silica, iron, magnesium, titanium, calcium, potassium, sodium oxides, mica, tourmaline, etc., which may be inherent in the parent rocks. The quality of china clay depends much upon the impurities present. China clay in mainly used in ceramics, textiles, paper, rubber, paints, cosmetics and pharmaceuticals industries. It is also used in insecticides, white cement manufacturing.
the uses and specifications of china clay in different industries are discussed below:
(a) ceramics:
the bis has not standardized any specification for use of china clay in ceramic industry. However, for the manufacture of ceramic products, good quality china clay is required which should have water elasticity of 32%, shrinkage after drying should not be more than 7%, and total shrinkage after firing at a temperature of 1300o c not more than 10-14%, grit should be low. For the manufacture of ordinary crockery and ceramic wares, presence of grit up to 2% is tolerated. But for the manufacture of high-class crockery, grit below 1% is generally preferred. In the manufacture of high-class ceramic products, the presence of lime, magnesia, iron oxides, alkalies and other impurities up to 2% is not harmful. Excess of iron, however, may color the products. Also for the manufacture of electrical switches, the iron content should be as low as possible.
(b) textile and paper coasting: -
china clay is utilized in textile industry and as a sizing and packing material. For this purpose, the clay should be white in color without tinting. Grit is the most objectionable ingredient. Oxides of magnesium and iron should be as low as possible. Dull white clay is utilized in making colored and khaki cloth.
china lay is used for paper coating purpose in order to provide a smooth, even surface and to impart a glaze. Various grades of paper quality china clay of fine mash are used depending up on the quality of paper required to be manufacture. The whiteness, ink absorption, chemical inertness, uniformity of particle size and retentive properties determine the suitability of china clay for use in paper coating.