“Ball Clay”-Processing, Properties, Uses & Formula

Ball clay

Ball Clay– What is it?, Properties, Chemical formula & Composition, Test, Mining & Processing, Uses, Suppliers & everything you need to know about Ball clays.

What is Ball clay?

Ball clays are kaolinite rich secondary clay which is available in dark brown to black colour due to relatively high organic impurity content. Once it fired, it will become white to lite cream colour. It consists of three major minerals that are kaolinite, mica & quartz. It is a high plastic clay and contains more fine particles. It is also known as plastic clay. The name ball clay came from the mining method of cutting the mud out in balls. Many properties match stoneware clay, but these stoneware never gives white product after burning.

Ball clays are characterised by higher plasticity, dry shrinkage and dry strength as compared to china clay. They are chemically impure and often contain a large proportion of silica, iron and titanium impurities.

The sedimentary clay also contains both carbonaceous matter and lignite in the agglomerate form (>50Mic) and colloidal form(<2 Mic). It’s believed that the carbonaceous material within the prescribed limit (<2wt %) influences the physical properties of the clay and also increases the unfired strength of clay. However, it increases porosity after firing, resulting in a decrease in fired strength. It also increases the casting thickness.

ball clay

ball clay

 

Ball clay Properties

The ball clay deposit is sedimentary and consists of numerous strata which frequently vary significantly in physical properties although perhaps not much in chemical composition. Ball Clay is generally called Kaolin, that had been transported from the primary decomposed parent, or igneous rock which were usually granite by nature via glacial displacement making It is a secondary clay, and in this process, it not only does it gain high organic impurities and iron contaminants but the material gets ground down into a finer particle size! Quality specifications of ball clay: Some relevant quality specifications of the ball and plastic clay are:

  • Residue/girt content on 45 microns (325 mesh) IS sieve should not be more than 2.0 wt%
  • Particles coarser than 25 microns should be~ 3.0 wt%
  • Particles fine than 2 microns should be~70 wt% Min
  • The water plasticity should be ~ 34 wt % Min
  • Unfired Strength (MOR) should not be less than 35.0 kg cm2.
  • Contents of Fe2o3 & TiO2 combined should not exceed 2.75 wt%, and the individual constituents should not be more than 1.5 wt%

 

Physical properties of Ball clay

Main features include high plasticity due to fine particles which give high green strength for handling the product at the green stage. Requires much more deflocculant to get required fluidity compared to china clay because of fine particles and organic impurities. High Green MOR compared to china clay due to more fine particles. Fired shrinkage is comparatively more due to high loss on ignition and particle size distribution. Green Modulus of Rupture: 65 Kg/cm2.

  1. Water absorption after Firing: Around 10%
  2. Ph value: From 6 to 8
  3. % of Dry Shrinkage : 3 to 4 %
  4. % of fired shrinkage: 4% to 6%
  5. Residue on 40 mesh : 1% to 3%
  6. Casting rate is comparatively low when compared to china clay in slip condition with same fluidity, viscosity and density.
  7. Drying time is slow compared to china clay.
  8. Ball clay should never tested for colour in the concentrated state since its density, and adsorbed salts give colour intensities which are misleading.

Chemical Formula & Composition of Ball clay

The Chemical formula of ball clay is Al2O3. 2SiO2.2H2O.

The chemical composition of ball clay varies very much from place to place even from one lot to another.

MineralPercentage
SiO245% to 55%
Al2O330% to 40 %
MgO0.1% to 0.5%
TiO20.5% to 2%
Fe2O30.50% to 1.5%
Cao0.1% to 0.5%
Na2O0.1% to 0.6%
Loss of IgnitionAround 14%

Ball clay Processing

Ball clays are sold directly from the mine without processing, other than the air-drying which may occur under favourable circumstances.

ball clay storage for use

ball clay storage for use

 

Ball clay storage for use But some cases Ball clay proceeded after mining before packing to remove impurities. Steps in the Ball clay processing are

 

  • Mining
  • Sieving
  • Settling
  • Fitter pressing
  • Drying
  • Packing

Mining:

Ball clay is extracted generally by a mechanical, hydraulic backhoe. Then it will be mixed with water and sent to sieve.

Sieving:

Then the ball clay slurry is passed through a series of sieves to remove the impurities. This sieve is passed up to 40 mesh.

Settling:

After sieving the slurry will be passed through a series of zig zak settling to allow clay particles to settle down. In this stage, the maximum amount of water will be remove.

Filter Pressing:

The slurry from the settled tank will be feed into the filter press to remove the water to form cake state clay.

Drying & packing:

The cake form ball clay dried in the atmosphere for some time. Then it is packed in 50 kgs bags and transported to the customer.

Normally Single ball clay is not used in the process because of much varying properties from one delivery to another delivery. So normally two or more ball clay is mixed and used in production process in sanitaryware.

 

Ball Clay Tests

Following are some of the test that is carried out in a laboratory where ball clay used as a raw material in the production process. Sample for testing will be taken from different areas from the clay leap so that the result will be accurate.

Washed ball clay for lab testing

Washed ball clay for lab testing

 

  1. Moisture Test
  2. Alkali Demand Test
  3. Residue Test
  4. Shrinkage test
  5. LOI Test
  6. Water Absorption Test
  7. MOR Test
  8. Casting Rate

 

Moisture Test:

This test is carried to find out the percentage of moisture content present in the received ball clay load supply. The formula for Percentage of Moisture is

Moisture % = ((W1 – W2)/W1)*100.

Where W1 is initial weight (100 gm),

W2 is Final weight after the sample has dried.

Alkali Demand Test. This test is carried out to find the Sodium Silicate solution required to obtain less than 20 this for ball clay slip. The formula used to calculate the alkali demand is,

Alkali Demand % = ((Z/2)/W1)*100 ,

whereas Z is grams of sodium silicate solution added & W1 is the weight of the clay taken initially.

Residue Test:

This test is carried out to find the residue percentage in the clay on 200 mesh sieve. The formula used to calculate the % of residue in clay

Residue % = W1/{((Density x 100) – 100 x 1.625)} x 100 ,

whereas W1 is weight of residue.

Shrinkage Test: This test is carried out to find the Dried shrinkage %, Fired shrinkage % & Total shrinkage % for ball clay.

The formula used to find the Dried Shrinkage is,

Dried Shrinkage % = (L1-L2)/L1 x 100.

The formula used to find the friend shrinkage is.

Fired shrinkage % = (L2-L3)/L3 x 100.

The formula used to find the Total shrinkage is,

Total shrinkage % = Dried shrinkage % + Fried shrinkage %

whereas L1 is the initial length of the casted sample bar,

L2 is the length of dried sample bar after drier,

L3 is the length of the fired sample after kiln.

LOI Test:

This test is used to find the loss of ignition of the clay. Weight loss during firing is called the loss of ignition. The formula used to find the LOI is,

LOI % = (W1-W2)/W1 x 100,

Whereas W1 is the initial weight of the sample taken,

W2 is the weight of the sample after firing from the kiln.

Water Absorption Test: Formula used to find the water absorption percentage is

Water absorption % = [W2-W1] x 100/ W1

whereas W1 is original dried sample weight,

W2 is the final weight of the sample after immersed in the boiling water.

Green MOR Test:

This test is to find the green Modulus of rupture of the ball clay. The formula used to find the Green MOR is

MOR = 8 x P x L / [ Π x D3],

Ball clay green MOR testing machine

Ball clay green MOR testing machine

 

L is the length in cm;

 

D is the diameter of the bar in cm.

Casting Rate:

To find the slip casting rate for an hour. Less than 20 Thixo slip is made by adding sodium silicate to the ball slip at 1.8 density. This ball clay slip is poured into a plaster mould and left for an hour and then drained, and left half an hour for drying then the casting rate is found by using vernier scale.

Find more tests taken in sanitaryware products here.

Ball Clay Suppliers

We have listed below some supplier of ball clay from around the world,

    • Imerys ceramics India Private Ltd. – IndiaAddress: Surya arcade, 4th floor,Begumpet,Hyderabad – 500016,India.Contact No: 040-30586666, 30689851, 30689877, 30682266, 30689880,07702070088, 09959911833
    • Kothari Clay industries. – Gujarat, India.Contact Person: Mr Chetan KothariAddress: Mahalaxmi Street, Post Office, Thangadh – 363530, Gujarat, India.Contact No: 09825393663, 02751-220263/220863Fax: 02751-220263
    • Ashvin ceramics. – India
    • Swastik Minerals. – India
  • Amarnath Industries. – IndiaContact Person: Mr Amarnath JhaAddress: Behind Arya Samaj School, Rathkhana Colony, Bikaner – 334001, Rajasthan, India.Contact No: 09414147777
  • Old Hickory Clay Company – USAAddress: 962 State Route 1241 Mayfield, KY 42066, USA.Contact No: 800-242-6885
  • Jannat Enterprise – Malaysia Address: kulim, Kedah, Malaysia.Contact No: 60-50230-15
  • Advance Clay Supplies – Malaysia Contact Person: Abdullah HassanAddress: Gombak, Kuala Lumpur, Malaysia, Zip code:68100.Contact No: 60-10-9828969, 60-109828969
  • Mita Madencilik Ltd – Turkey Address : Eskisehir, Seyitgazi, Turkey, Zip Code: 2600Contact Person:Takittin ErolTelephone:90-252-3822744Fax: 90-252-3824211

Functions: The major functions of the ball and plastic clays in ceramic bodies are:

  • Provide fine particles
  • Higher plasticity and workability
  • Higher dry and lower fired shrinkages
  • Higher unfired strength
  • Make ceramic bodies buff burning, low maturing and less translucent due to the presence of a large number of impurities.

Ball clays are also essential in tileware bodies for plasticity and workability for pressing and unfired strength required for the handling of pressed tiles.

Uses of Ball clay

  • Used as a raw material in sanitary ware production.
  • Ball clay is an essential raw material in sanitaryware production due to its green strength. It gives the sanitaryware handling strength in the green stage. Around 20% were used in the composition of sanitaryware production.
  • Used as a raw material in wall & floor tiles production
  • Around 14% used in floors and wall tiles production to give better particle size distribution for better density and whiteness to the product.
  • Used as a Raw material in Refractory Production
  • Because of the plasticity property of the ball clay, it is used in the refractory bricks production to give shaping to the product.
  • Used as Raw material in Ceramic clay pipe production
  • Due to the shaping property, it is used in ceramic clay pipe production.
  • Used as a raw material in Electrical insulators
  • It is used in electrical insulator production to give the insulation properties to the insulator.
  • Used in Tableware production
  • One of the raw material for the production of tableware. It gives better shaping and green strength to the tableware product.
  • Used as other than ceramic industries as filler & extender
  • Ball clay used in other than ceramic industries for its binding properties. It is used as a filler in paint, fertiliser, etc..

Conclusion

In this article we tried to cover as much as possible about ball clay, we know that nothing is perfect everything can be improved further so if you feel that we missed something that you like to add in this article please leave your comment below. Find more details about China clay here.

29 comments

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29 comments

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Barby 13 February 2020 - 4:24 am

Hi I asked about a kiln wash but didn’t say I would use Ball clay%60 to silica%40.
Would this work?

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vm3567 7 April 2020 - 7:55 pm

For kiln wash you need to use alumina .

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Barby 13 February 2020 - 1:59 am

will ball clay mix with silica to form a kiln wash?

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CLAY NPS 26 July 2019 - 4:21 pm

Great article on ball clay…

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FAYZE 26 July 2019 - 4:21 pm

what is the best ratio for ball clay and china clay in the sanitary ware production?

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RENU 26 July 2019 - 4:20 pm

Please provide phone number for all ball clay suppliers tat will be helpfull to all…

REPLY

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SAMBATH 26 July 2019 - 4:20 pm

Lots of information about ball clay.

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LAKSHMI 26 July 2019 - 4:20 pm

Its really good info on ball clay…Please provide more info on this…
Thanks in advance!!…

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LARA 26 July 2019 - 4:19 pm

is there an type of ball clay available?

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JAMES 26 July 2019 - 4:19 pm

Good collection of information about ball clay. ball clay is good for potters like me.

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RAVIKIRAN 26 July 2019 - 4:18 pm

Use full information

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MOHAMED MEKKI 26 July 2019 - 4:18 pm

What is the average value of density of ball clay “Egyptian ball clay” ?

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BELIN LINDON 26 July 2019 - 4:18 pm

What is the current Demand Supply and gap in India for Ball Clay?

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RAJESH 26 July 2019 - 4:17 pm

Super

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NASIR 26 July 2019 - 4:17 pm

we can supply ball clay in any quantity from Pakistan FOB Karachi,,Lab report is available on request.please call 00923228405051

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JULIE 26 July 2019 - 4:16 pm

Hi,
This is awesome information on ball clay. I am actually doing a school assignment using ball clay where i am trying to make jars. the thing is that i mixed the clay and water last Tuesday and the clay is still not manageable. really sticky and i can’t shape anything. is this normal with ball clay or is there some trick that you can show me to help the water evaporate quicker?

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Venkat Mani
Venkat Mani 28 July 2019 - 4:23 pm

Hi Julie,

A 2 to 3 days aging is enough for clay handling but i believe you have added more water to it. You can add a small amount of fine sand or quartz powder to the mix to make it workable clay mixer.

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ATUL SHARMA 26 July 2019 - 2:55 pm

Material

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ANUPAM BANERJEE 26 July 2019 - 2:54 pm

can anyone tell me the difference between ball clay & washed ball clay ? how it is used in sanitary ware & tiles?

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Venkat Mani
Venkat Mani 28 July 2019 - 4:24 pm

washed ball clay is processed ball clay, means ball clay is mixed with water and then filtered and dried , this is called as washed ball clay. washed ball clay is more pure from salt and soluble content because it washed away during the process of ball clay washing.

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GABRIEL 26 July 2019 - 2:53 pm

please Sir, i need more research on ball….
the Mineralogy and geochemistry of ball clay

thanks

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SK 26 July 2019 - 2:53 pm

Mere pass ball clay ki mines Jo Lena chahta h plz information
7691894586
Sandeep gujjar

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SIVA POOJA 26 July 2019 - 2:52 pm

So awesome information about ball clay.Thanks for sharing the knowledge to all

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VENKAT REDDY 26 July 2019 - 2:52 pm

VERY GOOD INFORMATION SHARED.

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DR. TUKUR DIKKO M. ZAURO 26 July 2019 - 2:51 pm

Indeed, useful information.

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NELSUN 26 July 2019 - 2:51 pm

What is the MOR?

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PAULSON MANDAKATH 26 July 2019 - 2:51 pm

Thank you very much for sharing valuable information

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KRUPA SHANKAR 26 July 2019 - 2:50 pm

Dear Mr. Venkatmani,

Like the article for Ball Clay & China Clay, please also throw us some light about the Feldspar’s and other Glaze Materials, their uses, properties, testing procedures and standards physical and chemical properties.

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NATRAH RUSLI 26 July 2019 - 2:50 pm

it stated that ball clay is kaolinitic or kaolinite which means it related to kaolin..I have question regarding whiteware ceramic, why should we combine kaolin and ball clay incase ball clay itself is already kaolin?

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