Beneficiation of China Clay. Beneficiation process Kaolin.

Major Impurities in China Clay are quartz, mica, feldspar and iron oxide minerals. China clay is an important raw material for many industries like rubber, textile, paper, pharmaceutical, cosmetic, paint, and refractory besides ceramic industry. For any value-added application, the run-of-mines (ROM) clay is to be processed to remove or reduce the ancillary mineral impurities associated with the same. Beneficiation helps to achieve required particle size and size distribution and also to attain other physical and optical properties for the clay.
Beneficiation of China Clay. Beneficiation process Kaolin.

How many types of Kaolin? Classification of Kaolin.

Ordinary washing process does not deprive nature kaolin of their accompanying impurities and according to the presence of theme impurities kaolins are graded as follows.
  •       Pure kaolins do not contain more than 5% of free silica and 2% of fluxes. After firing, the best qualities form mass of milky whiteness. They are used in the manufacture of porcelain and fine earthenware, and in several non-ceramic industries.
  •       Alkaline kaolins may contain about 5% of alkalis derived from feldspar and mica. The proportion of iron may be up to 2%. They can be purified by very careful washing which removes the greater part of alkalis, but are inferior to the first group. These clays are used for making earthenware and fine pottery.
  •       Siliceous kaolins contain up to 25% free silica in the state of impalpable powder. These clays are not very plastic as can be judge from their composition and they are used in the making of porcelain and certain kind of faience where very plastic bodies are not required.
  •       Alkali siliceous kaolins contain a considerable proportion of both alkalis and silica; they partake of the properties of the two preceding kinds but are less refractory.
  •       Ferruginous kaolins prevent a white body being produced on firing. They are chiefly used for the manufacturing of refractory materials provided they do not contain too much alkali. Kaolins with high lime content are known as calcarious.

What is Kaolin or China Clay? What is Kaolinite? What is the chemical formula of China Clay or Kaolin?

The name Kaolin has been derived from the Chinese word Kao-ling, which means high ridge and also it is the name of a hill near Jauchu Fu, from where the used for making porcelain, was obtained by the ancient Chinese people. The term is now generally applied to those residual clays usually white in colour and derived from rocks composed entirely of feldspar or another similar minerals, containing no or very little amount of iron oxide. These clays contain a high percentage of the mineral kaolinite together with other hydrous alumino-silicates. In England the term china clay is applied to the white plastic clays derived from washing the decomposed Cornish or Dovonain granite. But for all practical purposes Kaolin or China clay may be taken as identical containing approximately 46% silica (SiO2), 40% alumina (Al2O3), and 14% water (H2O) and corresponding to the formula Al2O3.2SiO2.2H2O.
China Clay, Kaolin, Ceramic, Kaolinite
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What is Laterite? What is Morum? Characteristics of Laterite or Morum.

These represent the particular residual clay formed by the weathering of bauxite rocks yielding a product in which silica (SiO2) has been largely eliminated and aluminium and iron hydroxides predominate. The changes, which bring about its formation, appear to be peculiarly characteristic of the tropics. Two typical analyses of residual Laterite are given below. The first one is of American origin and the second one is from Nalhati in India. In India lateritic clays containing very high proportion of iron are known as Morum and these are chiefly used in road making. They are very sticky when wet but become quite hard when dries up.
Non soluble matter

What is Laterite? What is Morum? Characteristics of Laterite or Morum.
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What is the Properties of Ceramic? What is the Characteristics of Ceramic?

Characteristics of Ceramics bodies are given below:
  •     Ceramics are hard and brittle.
  •     Strong in compression.   
  •     Weak in shearing and tension. 
  •     Withstands chemical erosion due to acidic or caustic environments.
  •     Extreme hardness.
  •     Ceramic Bodies are High wear resistance.
  •     Extreme hardness can reduce wear caused by friction.
  •     Corrosion resistance.
  •     Ceramic products are Heat resistance.
  •     Low electrical conductivity.
  •     Low thermal conductivity. 
  •     Low thermal expansion.
  •     Poor thermal shock resistance.

What is the Properties of Ceramic? What is the Characteristics of Ceramic?
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What is Secondary Clay? What is Transported Clay? Classification of Clay.

Clay may broadly divide into two types, one is Primary Clay and another one is Secondary Clay

Secondary Clay or Transported Clay: When the residual clays are removed by transporting agents such as water, ice, wind etc. And those clays are deposited at lower levels, these types of clays are called secondary clay or transported clay. These transported clays are usually but not always less pure than primary clay. The secondary clay deposits are generally formed by sedimentation; hence those clays can be distinguished from the residual clay chiefly by their stratification and also by the fact that they commonly bear no direct relation to the underlying rock on which they may rest.

Example: Fire Clay, Ball Clay, Shale, Loams, Loess etc.

What is Secondary Clay? What is Transported Clay? Classification of Clay.
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