Comprehensive Guide to Ball Clay: Properties, Composition, Processing, and Applications

Ball clay is a kaolinite-rich secondary clay known for its distinctive dark brown to black color, transitioning to white or light cream upon firing. This versatile clay, also referred to as plastic clay, contains major minerals such as kaolinite, mica, and quartz. In this guide, we’ll explore the properties, chemical formula, composition, testing methods, mining and processing, suppliers, and diverse applications of ball clays.

[toc]

What is Ball clay?

Ball clays are high-plasticity clays, characterized by fine particles and a chemical composition containing silica, iron, and titanium impurities. The name “ball clay” originated from the method of extracting the clay in spherical shapes.

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

Plasticity: Higher than china clays, resulting in increased green strength.

Chemical Impurities: Commonly includes silica, iron, and titanium.

Carbonaceous Matter: Influences physical properties and unfired strength but increases porosity after firing.

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 clays are:
• Residue/Girt Content: ≤ 2.0 wt% on 45 microns (325 mesh) IS sieve.
• Coarse Particles: ~ 3.0 wt% finer than 25 microns.
• Fine Particles: ~ 70 wt% finer than 2 microns.
• Water Plasticity: ~ 34 wt%.
• Unfired Strength (MOR): ≥ 35.0 kg cm2.
• Fe2O3 & TiO2: Combined ≤ 2.75 wt%, individual constituents ≤ 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.
• Water absorption after Firing: Around 10%
• Ph value: From 6 to 8.
• % of Dry Shrinkage : 3 to 4 %.
• % of fired shrinkage: 4% to 6%.
• Residue on 40 mesh : 1% to 3%.
• Casting rate: Comparatively low with china clay in slip condition with same fluidity, viscosity and density.
• Drying time: Slow compared to china clay.

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.

Mineral	Percentage
SiO2	45% to 55%
Al2O3	30% to 40 %
MgO	0.1% to 0.5%
TiO2	0.5% to 2%
Fe2O3	0.50% to 1.5%
Cao	0.1% to 0.5%
Na2O	0.1% to 0.6%
Loss of Ignition	Around 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 But some cases Ball clay proceeded after mining before packing to remove impurities.

Steps in the Ball clay processing are,

1. Mining:  Extracted mechanically using a hydraulic backhoe or using jet pump. extracted clay is mixed with water.
2. Sieving:  Slurry passed through sieves up to 40 mesh. and also passed through magnets to remove iron impurities.
3. Settling: Clay particles settle through zig-zag settling. Water will be removed from the top.
4. Filter Pressing: Slurry fed into a filter press to form cake state clay. this process reduce the water content in clay to around 17 %.
5. Drying & Packing: Cake clay dried, weighed and packed in different bags based on the customer requirement.

Normally Single ball clay is not used in the manufacturing 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.

Ball Clay Suppliers:

A list of global suppliers is provided for those seeking reliable sources of ball clay.

• 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. – India Contact Person: Mr Amarnath JhaAddress: Behind Arya Samaj School, Rathkhana Colony, Bikaner – 334001, Rajasthan, India.Contact No: 09414147777
• Old Hickory Clay Company – USA Address: 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.

Uses of Ball clay:

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.

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.

Raw material in Refractory Production: Because of the plasticity property of the ball clays, it is used in the refractory bricks production to give shaping to the product.

Raw material in Ceramic clay pipe production: Due to the workability property, it is used in ceramic clay pipe production.

Raw material in Electrical insulators: It is used in electrical insulator production to give the insulation properties to the insulator.

Raw Material 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 filler & extender: Ball clay used in other than ceramic industries for its binding properties. It is used as a filler in paint, fertilizer, etc..

Conclusion:

While this guide covers a wide range of aspects related to ball clay, we acknowledge the potential for further improvements. If there are additional insights or information you’d like to contribute, please share your comments below.

Find more details about China clay here.