CHINA CLAY/ KAOLIN
One of the purest of the clays, composed chiefly of the mineral kaolinite usually formed when granite is changed by hydrothermal metamorphism. Usage of the terms china clay and kaolin is not well defined; sometimes they are used synonymously for a group of similar clays,
China clays have long been used in the ceramic industry, especially in fine porcelains, because they can be easily molded, have a fine texture, and are white when fired. France's clays are made into the famous Sèvres (see A. Brongniart ) and Limoges potteries. These clays are also used as a filler in making paper. In the United States, deposits are found primarily in Georgia, North Carolina, and Pennsylvania; china clay is also mined in England (Cornwall) and France.
China clays have long been used in the ceramic industry, especially in fine porcelains, because they can be easily molded, have a fine texture, and are white when fired. France's clays are made into the famous Sèvres (see A. Brongniart ) and Limoges potteries. These clays are also used as a filler in making paper. In the United States, deposits are found primarily in Georgia, North Carolina, and Pennsylvania; china clay is also mined in England (Cornwall) and France.
USES OF CHINA CLAY
China clay in ceramic manufacture, porcelain; bone china; earthenware; white tile body; graniteware; white stoneware; glazes.
Paper manufacturing Miscellaneous, paint; plaster; alum; ultramarine; whitewash; drugs; soap and face powder; wine clarification; polishing powders; lead pencils.
Paper and board, coating clays; fillers; brush coating clays; machine coating clays.
Rubber
Paint and distemper
Leather
Cosmetics, insecticides, dusting and medicinal
Textiles
Linoleum
White cement
Ultramarine
Plastics
Paper manufacturing Miscellaneous, paint; plaster; alum; ultramarine; whitewash; drugs; soap and face powder; wine clarification; polishing powders; lead pencils.
Paper and board, coating clays; fillers; brush coating clays; machine coating clays.
Rubber
Paint and distemper
Leather
Cosmetics, insecticides, dusting and medicinal
Textiles
Linoleum
White cement
Ultramarine
Plastics
SPECIFICATION OF CHINA CLAY
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SPECIFICATION OF WHITE CLAY MARKED
SiO : 61.11 Al2O3 : 24.21 Fe2O3 : 1.06 TiO2 : 1.80 CaO : 1.46 MgO : Tr Na2O : 0.32 K2O : 0.60 L O I : 09.34 |
SPECIFICATION OF CHINA CLAY FOR WHITE CEMENT
Quality Specifications for Kaolin:
Compositions KAOLIN (Wt. %)
SiO2 68-72
Al2O3 18-20
Fe2O3 0.5%-0.6%
CaO <5.0
MgO <1.0
SO3 <0.5
TiO2 0.9% Max.
Chloride 0.05% Max.
Fluoride <0.1
Na2O <0.4
K2O 1-2%
Cr2O3 <0.01
Mn2O3 <0.02
P2O5 <0.3
Moisture 5% Max.
Size <50mm
Compositions KAOLIN (Wt. %)
SiO2 68-72
Al2O3 18-20
Fe2O3 0.5%-0.6%
CaO <5.0
MgO <1.0
SO3 <0.5
TiO2 0.9% Max.
Chloride 0.05% Max.
Fluoride <0.1
Na2O <0.4
K2O 1-2%
Cr2O3 <0.01
Mn2O3 <0.02
P2O5 <0.3
Moisture 5% Max.
Size <50mm