a) kaolin (china clay)
Kaolin is also called china clay, including the type of primary clay (residue) that serves as a key component in making porcelain mixture, and is used in ceramic stoneware and white Earthenware. Kaolin is used to binders and enhancing the strength of the ceramic body at high temperatures, porcelain, goods fireproof (refractory), also used as reinforcement material in the manufacture of glazes.
Figure 37. Mining kaolin
The properties of kaolin are:
(1) coarse grained
(2) no plastic
(3) the relatively pure
(4) the color white
(5) a high melting point is 1800 ° C.
In Indonesia, these materials are in some places such as Aceh, North Sumatra, West Java, East Java, South Sumatra, Bangka, Belitung, Central Sulawesi, Kalimantan.
b) Ball clay
Ball clay including secondary types of clay (sediment / sludge) having particles so fine that the level of plasticity and dry strength levels high and contains a lot of organic material. Ball clay is generally used as ingredients to make white ceramic (ceramic smooth and in an email, also to make the clay slip cast thinner. In the plastic mass of this material can increase the power of labor and dried. The properties of ball clay common:
(1) fine-grained.
(2) very high plasticity.
(3) high shrinkage of 20%.
(4) high dry strength.
(5) the melting point temperature of 1300oC.
(6) gray.
Ball clay is located in West Java, Riau, Brata Kalimantan, Central Kalimantan, South Kalimantan, North Sulawesi, Central Java, East Java, Bangka, Belitung and can also be obtained everywhere (rice, moor).
c) Stoneware
Stoneware clay is a material that is plastis.Tanah clay refraktoris These include the type of clay secondary (sediment) that has low shrinkage, fine-grained, and is widely used to make objects binders and colorants. Stonewareakan produce solid objects and watertight when burned at a temperature of 1250 ° C – 1300 ° C without deformation. Stoneware is very advantageous because it can be directly used to make ceramic objects directly (single ingredient) without mixing with other materials with satisfactory results.
Stoneware common traits:
(1) grained,
(2) plastic,
(3) low shrinkage,
(4) low porosity,
(5) the melting point of the soil reaches a temperature of 1400 ° C,
(6) the raw color gray, dirty yellow,
(7) fireproof,
The land there is, among others, in West Java and Karimun.
d) Earthenware
Earthenware including the type of secondary soil (sediment). The clay is easily found in various regions is plastic, with a finely grained iron content is high enough. This clay has a sufficient degree of plasticity, so malleable, but also has a high shrinkage rate as well. Having burned his strength diminished and very porous. Absorption rate (porosity) and 3% more water, low combustion temperatures between 900 ° C-1060 ° C, the color of brown and red fuel melting point of about 1100 ° C-1200 ° C
Red clay is widely used in industrial tile, brick, and pottery rough and smooth. Natural color is not bright red but red rust, because of its iron content reaches 8%. When glazed colors will be richer, especially using lead glaze. But this glaze has not recommended because of the toxic effects of lead are dangerous. Earthenware clay is widely used in the manufacture of ceramics Earthenware, pottery, bricks, tiles, and can be used as a dye in the glaze.
Earthenware common traits:
(1) plastic,
(2) a fine-grained
(3) The iron content is high enough
(4) the raw color red, brown, gray, black,
(5) combustion temperature between 900 ° C-1060 ° C
Earthenware clay is widely available in North Sumatra, West Sumatra, West Java, Central Java and Yogyakarta,
e) Fire Clay
Fire clay is a secondary soil (sediment) which is resistant to heat and does not deform because it has a high melting point is 1600ºC-1750ºC. Most clay fire-resistant light-colored (white) to dark gray to black head and is found in nature in the form of solid chunks, some of which yield high alumina and low alkali levels. Are classified as fireproof clay is clay that is resistant burnt at high temperatures without changing the shape, for example, kaolin and refractory minerals such as alumina and silica.
Fireclay serves as a refractory material to make items such as refractory bricks and furnace equipment. In fireclay ceramic body is used as a compound to increase the ability of the form-making stoneware and porcelain products.
General properties of fire clay:
(1) tend to be plastic,
(2) coarse grains,
(3) the low level of absorption,
(4) depreciation medium,
(5) high-temperature-resistant (refractory).
f) Bentonite
Bentonite clay also include the type of secondary (sediment) are highly plastic and fine-grained so used to add keplastisanbadan ceramics. In the glaze, this mineral serves as a binder. Bentonite clay monmorilinit including types derived from the weathering of volcanic rocks. To add plasticity clay, one part bentonite ballclay equivalent of three parts.
Picture 40. Mining of bentonite
Bentonite general properties:
(1) highly plastic,
(2) a fine-grained,
(3) the melting point of 1200ºC.
In Indonesia, bentonite are found in West Java, are also found in Aceh, North Sumatra, Riau, South Sumatra, Bengkulu, Central Java, East Java and North Sulawesi.
Picture 41.Bahan-plastic ceramic material