China Clay also called as Kaolin is formed by chemical weathering of rocks(Feldspar) which are rich in aluminum silicate. Generally a white mineral, but is often found in Pink-Orange-Red colors due to Iron contamination. Less rust concentrations have a color of white, yellow or light orange. This mineral is highly valued for its whiteness, but […]

Different techniques are used for separating clay from its impurities. These can be classified into Mechanical and Chemical Separation techniques.Mechanical techniques are based on particle size and other physical properties. Chemical techniques are based on chemical composition.
These days even small scale industries use Classifiers like hydro cyclone equipments. In this process, in every step the […]

In India, most of the washing plants follow a very simple process of beneficiation: The mined clay boulders are first crushed into small lumps and mixed with water and sodium silicate in a high speed blunger. The blunged slurry is then passed through a series of sieve (filter) systems starting from coarse to fine […]

In the German Method, beneficiation is more mechanized and makes use of powered mechanical equipments.
Normally, the processing location is away from the mines site and the mined clay is transported to the processing plant using trucks.
In the processing plant, the crude clay is charged into horizontal blungers with perforated sides. In this blunger, clay is […]

After settling, the liquid clay suspension contains about 25 to 35% solid matter and this clay suspension at this stage is now allowed to flow through drying platforms situated close to the delivery shipment point.
In the drying platforms, the clay mud is placed on open hearts called ‘dry pans’ where it gets dried. Hot air […]

Then the clay slurry enters into long shallow vats which are divided into 5 or 6 sections, each section being a step lower than the former. The stream of clay suspension runs through these channels very slowly and the speed can be regulated based on the requirement of fineness of clay. The clay suspension slurry […]

The clay suspension is collected into a main channel and is taken into a shallow tank which is otherwise called sand pit, where all the heavy materials like rock, chips, sand etc are deposited.
The clay water slurry is then pumped to the ground surface and mixed with another stream of fresh water to dilute the […]

There are two different methods commonly followed for washing of kaolin:

English method
German method

English method:
In south western part of England, rich china clay deposits are available at depths of 10 to 20 feet, surface material called over burden.
In this method, first the decomposed rock containing kaolin is loosened by hand rake, flown up by dynamite and […]

Pure kaolin: These kaolins are known for their milky white colour and they do not contain more than 2% of fluxes and 5% of free silicious materials. These clays are mainly used in the manufacturing of ceramic porcelains and ceramic fine earthenware. These are also used in several non-ceramic industries like pharmaceutical, paper, health care […]

China clay (also known as ‘kaolin’ – dervied from Chinese ‘kauling’ meaning ‘ that which is available in the hills near Jauchau Fu’). China Clay contains a very high percentage of the mineral kaolinite together with hydrous alumino-silicates. Basically these are white in colour and so after firing gives out white colour.
Since it is a […]