Ceramic Tile



Background

Wall and floor tile used for interior and exterior decoration belongs to a class of ceramics known as whitewares. The production of tile dates back to ancient times and peoples, including the Egyptians, the Babylonians, and the Assyrians. For instance, the Step Pyramid for the Pharoah Djoser, built in ancient Egypt around 2600 B.C. , contained colorful glazed tile. Later, ceramic tile was manufactured in virtually every major European country and in the United States. By the beginning of the twentieth century, tile was manufactured on an industrial scale. The invention of the tunnel kiln around 1910 increased the automation of tile manufacture. Today, tile manufacture is highly automated.

The American National Standards Institute separates tiles into several classifications. Ceramic mosaic tile may be either porcelain or of natural clay composition of size less than 39 cm2 (6 in.2). Decorative wall tile is glazed tile with a thin body used for interior decoration of residential walls. Paver tile is glazed or unglazed porcelain or natural clay tile of size 39 cm2 (6 in.2) or more. Porcelain tile is ceramic mosaic tile or paver tile that is made by a certain method called dry pressing. Quarry tile is glazed or unglazed tile of the same size as paver tile, but made by a different forming method.

Europe, Latin America, and the Far East are the largest producers of tile, with Italy the leader at 16.6 million ft.2/day as of 1989. Following Italy (at 24.6 percent of the world market) are Spain (12.6 percent), Brazil and Germany (both at 11.2 percent), and the United States (4.5 percent). The total market for floor and wall tile in 1990 according to one estimate was $2.4 billion.

The United States has approximately 100 plants that manufacture ceramic tile, which shipped about 507 million ft.2 in 1990 according to the U.S. Department of Commerce. U.S. imports, by volume, accounted for approximately 60 percent of consumption in 1990, valued at around $500 million. Italy accounts for almost half of all imports, with Mexico and Spain following. U.S. exports have seen some growth, from $12 million in 1988 to about $20 million in 1990.

Because the tile industry is a relatively mature market and dependent on the building industry, growth will be slow. The United States Department of Commerce estimates a three to four percent increase in tile consumption over the next five years. Another economic analysis predicts that 494 million ft.2 will be shipped in 1992, a growth of about 4 percent from the previous year. Some tile manufacturers are a bit more optimistic; an American Ceramic Society survey showed an average growth of around 36 percent per manufacturer over the next five years.

Raw Materials

The raw materials used to form tile consist of clay minerals mined from the earth's crust, natural minerals such as feldspar that are used to lower the firing temperature, and chemical additives required for the shaping process. The minerals are often refined or beneficiated near the mine before shipment to the ceramic plant.

The raw materials must be pulverized and classified according to particle size. Primary crushers are used to reduce large lumps of material. Either a jaw crusher or gyratory crusher is used, which operate using a horizontal

The initial step in ceramic tile manufacture involves mixing the ingredients. Sometimes, water is then added and the ingredients are wet milled or ground in a ball mill. If wet milling is used, the excess water is removed using filter pressing followed by spray drying. The resulting powder is then pressed into the desired tile body shape.
The initial step in ceramic tile manufacture involves mixing the ingredients. Sometimes, water is then added and the ingredients are wet milled or ground in a ball mill. If wet milling is used, the excess water is removed using filter pressing followed by spray drying. The resulting powder is then pressed into the desired tile body shape.
squeezing motion between steel plates or rotating motion between steel cones, respectively.

Secondary crushing reduces smaller lumps to particles. Hammer or muller mills are often used. A muller mill uses steel wheels in a shallow rotating pan, while a hammer mill uses rapidly moving steel hammers to crush the material. Roller or cone type crushers can also be used.

A third particle size reduction step may be necessary. Tumbling types of mills are used in combination with grinding media. One of the most common types of such mills is the ball mill, which consists of large rotating cylinders partially filled with spherical grinding media.

Screens are used to separate out particles in a specific size range. They operate in a sloped position and are vibrated mechanically or electromechanically to improve material flow. Screens are classified according to mesh number, which is the number of openings per lineal inch of screen surface. The higher the mesh number, the smaller the opening size.

A glaze is a glass material designed to melt onto the surface of the tile during firing, and which then adheres to the tile surface during cooling. Glazes are used to provide moisture resistance and decoration, as they can be colored or can produce special textures.

The Manufacturing
Process

Once the raw materials are processed, a number of steps take place to obtain the finished product. These steps include batching, mixing and grinding, spray-drying, forming, drying, glazing, and firing. Many of these steps are now accomplished using automated equipment.

Batching

Mixing and grinding

Spray drying

Forming

Drying

Glazing

Firing

Byproducts

A variety of pollutants are generated during the various manufacturing steps; these emissions must be controlled to meet air control standards. Among the pollutants produced in tile manufacture are fluorine and lead compounds, which are produced during firing and glazing. Lead compounds have been significantly reduced with the recent development of no-lead or low-lead glazes. Fluorine emissions can be controlled with scrubbers, devices that basically spray the gases with water to remove harmful pollutants. They can also be controlled with dry processes, such as fabric filters coated with lime. This lime can then be recycled as a raw material for future tile.

The tile industry is also developing processes to recycle wastewater and sludge produced during milling, glazing, and spray-drying. Already some plants recycle the excess powder generated during dry-pressing as well as the overspray produced during glazing. Waste glaze and rejected tile are also returned to the body preparation process for reuse.

Quality Control

Most tile manufacturers now use statistical process control (SPC) for each step of the manufacturing process. Many also work closely with their raw material suppliers to ensure that specifications are met before the material is used. Statistical process control consists of charts that are used to monitor various processing parameters, such as particle size, milling time, drying temperature and time, compaction pressure, dimensions after pressing, density, firing temperature and time, and the like. These charts identify problems with equipment, out of spec conditions, and help to improve yields before the final product is finished.

The final product must meet certain specifications regarding physical and chemical properties. These properties are determined by standard tests established by the American Society of Testing and Materials (ASTM). Properties measured include mechanical strength, abrasion resistance, chemical resistance, water absorption, dimensional stability, frost resistance, and linear coefficient of thermal expansion. More recently, the slip resistance, which can be determined by measuring the coefficient of friction, has become a concern. However, no standard has yet been established because other factors (such as proper floor design and care) can make results meaningless.

The Future

In order to maintain market growth, tile manufacturers will concentrate on developing and promoting new tile products, including modular or cladding tile, larger-sized tile, slip- and abrasion-resistant tile, and tile with a polished, granite or marble finish. This is being accomplished through the development of different body formulations, new glazes, and glaze applications, and by new and improved processing equipment and techniques. Automation will continue to play an important role in an effort to increase production, lower costs, and improve quality. In addition, changes in production technology due to environmental and energy resource issues will continue.

Where To Learn More

Books

Bender, W. and F. Handle, eds. Brick and Tile Making: Procedures and Operating Practices in the Heavy Clay Industries. Bauverlag GmbH, 1982.

Jones, J. T. and M. F. Berard. Ceramics: Industrial Processing and Testing. Iowa State University Press, 1972.

Pellacani, G. and T. Manfredini. Engineered Materials Handbook. ASM International, 1991, pp. 925-929.

Periodicals

Burzacchini, B. "Technical Developments in Ceramic Tile Glazes and Related Applications," American Ceramic Society Bulletin. March, 1991, pp. 394-403.

Fugmann, K. "Rapid Changes in Tile Technology," Tile & Brick International. March, 1991, pp. 165-166.

Gehringer, George. "Tile Glossary: A Guide to Techniques and Surface Designs," American Ceramic Society Bulletin. December, 1990, pp. 1950-1952.

Geiger, Greg. "Developments in the Tile Industry," American Ceramic Society Bulletin. December, 1991, pp. 1879-1885.

L. S. Millberg



User Contributions:

1
speed Management consultants pvt .ltd
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Apr 14, 2007 @ 4:04 am
important for new enterpenures,mamufactring process more valuable if the machinary make also available with cost of project.
2
ask18
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Nov 18, 2010 @ 4:04 am
can we use bottles and plastic materials in making floor tiles?
3
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Sep 2, 2011 @ 8:08 am
It is interesting, such will encourage small scale enterprises.
4
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Nov 25, 2012 @ 7:07 am
can we use bottles and plastic materials in making floor tiles?
5
keisham sinshupal
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Aug 2, 2013 @ 4:04 am
everything is fine but one thing i would like to know how can i decide the best quality for raw material see is it depend on clay quality.
6
Josh
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Aug 10, 2013 @ 7:19 pm
I am working in a tile manufacturing company and most of the time our problems are all the same. Big in size, small in size, matte in color and sometimes shiny. In short, we cannot get the exact specifications that the management set. They are trying to push us but we cannot anything from them as if they are just starting but they invested a lot. I really wanted to help the company but i only have limited knowledge since i am new in tile industry. Can you recommend any reading materials or trainings when it comes to wall and floor tiles manufacturing? I am just concern with the company because as per my observation, they are wasting their money.
7
Sanjay passary
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Jun 29, 2015 @ 1:13 pm
I have a wall tile industry but we are not able to produce quality tiles.pl.help me with the detail raw material and process or refer some books where we can get the detais to overcome our problem
8
Sanjay passary
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Jun 29, 2015 @ 1:13 pm
I have a wall tile industry but we are not able to produce quality tiles.pl.help me with the detail raw material and process or refer some books where we can get the detais to overcome our problem

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