3. ceramic
Ceramics include all articles, which are
essentially silicates.
Those articles that are made of clay are
mainly known as ceramics.
4. ceramic
Ceramic and anti-melting materials
industries represents one of seven major
industries in the Egyptian market. It
represents 7% of the production value in
Egyptian Industrial sectors.
5.
6. Properties of ceramic
• High corrosion resistance
• High resistance to rust
• Low temperature conductivity
• Low electrical conductivity
7. Uses of ceramic
• Personal use: glassware, Windows, pottery,
dinnerware, tiles and ceramics, lenses.
• Medical field: compensating devices for
bony joints, dental.
• Military industries: materials for vehicle
body ground, sea and air sensors
• Computer domain: insulation,
transportation and resistors capacitors.
8. Raw materials
The principal raw materials are sand,
feldspar, ball clay, china clay, kaolin, talc
and other materials that are used during the
manufacturing process, such as soda ash,
sodium silicate, calcium carbonate.
9. Location of raw materials
1-Bentonite
2-Kaolin
3-Whitesand
4-limestone
10. Function of raw materials
1-clay
a)Produces a light colouring during firing
b)Gives plasticity and binding characteristics
to the mass
c)Enhances mechanical characteristic in the
fired tiles
d)Produces good flow properties
e)Gives a good density level during firing due
to the individual characteristic of the clays.
11. Function of raw materials
2-feldspar
a)feldspars play an important role in achieving the
vitreous nature of the body and the high
mechanical resistance of the product at the end
of the firing stage.
b)Acting as a flux, feldspars also facilitate drying
and release of gas during firing like other non-
plastics.
12. Function of raw materials
3-silica
a)facilitate escape of gases during drying and
firing.
b)reduces drying shrinkage and increases the
whiteness of the fired body
13. Function of raw materials
4-talc
used in small quantities (2-6%) in the vitrified
tile body composition to enhance the
fluxing action of feldspathic materials.
15. Chemical Analysis by X-Ray
Fluorescence Methodology
The basic principle of XRF involves irradiating a sample with
incident X-rays and measuring the secondary X-rays
emitted.
These secondary X-rays which are characteristic of each
element in the sample are detected and measured to
give a full analysis of the sample.
XRF is a method for measuring elemental contents of raw
materials and body formulations but not for identifying the
mineralogy.
16. Chemical Analysis by X-Ray
Fluorescence Methodology
Conducted for a wide range of purposes for material
identification and characterization to quality control
monitoring.
The types of materials that can be analyzed by XRF include
clay, sand feldspar, and limestone.
chemical analysis involves the determination of SiO2,
Al2O3, Fe2O3, TiO2, MgO, Na2O, K2O, and CaO together
with loss on ignition at about 1000°C.
17. Chemical Analysis by X-Ray
Fluorescence Methodology
There are 2 sample preparation techniques namely
pressed pellet and fused bead.
18. Pressed pellet
Samples are grinded into powder form and pressed into discs.
More suitable for samples with a particular similar mineralogy
composition such as limestone.
May have identical chemical composition but may differ in
terms of mineralogical make-up and particle size.
Contamination increases with reduced particle size and an
increase in surface area.
Preparing the samples using the pressed pellet method is
convenient and relatively easy but would not be suitable if a
wide range of samples are to be analysed.
19. Fused bead
Carried out by first weighing the ignited sample with a flux
such as lithium borate into a platinum dish and subjecting
the mixture to high temperatures.
21. X-Ray Fluorescence spectrometers
Two types of X-Ray Fluorescence spectrometers namely
the sequential spectrometer and simultaneous
spectrometer.
Simultaneous spectrometers are easier to operate as each
channel has its own separate crystal, collimator and
detector.
The range of elements that can be analysed is limited by
the number of pre-determined fixed channels.
For the sequential spectrometer, the equipment which is
relatively much costlier is able to analyze a very wide
range of elements.
22. Thermal Testing
Yield crucial information that is used to characterise the
suitability of new materials, troubleshoot defects and
monitor the quality of incoming raw materials.
Thermoanalytical methods such as dilatometry and
TG-DTA.
23. Thermal testing
Dilatometer
method for the determination of dimensional changes
versus temperature when the sample undergoes a
controlled temperature programme.
There are two types of dilatometry analysis namely
irreversible and reversible thermal expansion.
24. Irreversible thermal expansion
This is expansion of a dry, unfired material as it is
subjected to a heating process.
Evaluation of the expansion during firing can
provide useful information such as identification of
the type of clay be it kaolin, illite...etc
25. The raw dilatometric curve for Clay 1 is characteristic of an illitic clay,
where there is a constant plateau between the temperature ranges of
600-900°C.
The raw dilatometric curve for sample Clay 2 is typical of a kaolinitic
clay. Rapid contraction occurs from about 530°C.
26. Reversible thermal expansion
Performed on fired ware samples such as fired clay, body
and glaze samples to measure the coefficient of thermal
expansion (COE).
This parameter determines to a certain extent the
compatibility of the ceramic body and glaze.
Incompatibility could lead to crazing of the glaze and also
affects its planarity
28. Simultaneous Thermal Analysis
Simultaneous Thermal Analyser (TG-DTA) simultaneously
carries out DTA (Differential thermal analysis) and TG
(Thermal gravimetric analysis).
The temperature range is from room temperature to
1080°C.
DTA is used to establish the temperatures at which
reactions may occur that involve thermal effects in the
material for e.g. emission of gases or vapours, reactions
with formation of new crystalline phases...etc.
The temperatures at which the endothermic or exothermic
reactions occur are used to identify the material.
29. Simultaneous Thermal Analysis
TG quantitatively evaluates increases or losses in weight of
the material caused by the corresponding oxidation
reactions, vapour or gas reactions.
Uses
Determine the amount of weight loss due to gaseous
decomposition of organic or carbonate content...etc and
their temperature ranges.
Monitor the changes of incoming raw materials (such as
clay deposits, raw material lots or different suppliers) to
predict the effect on the firing process and production
batches.
30. The TG-DTA analysis for limestone sample showed an
endothermic peak at 912°C with a total weight loss of
43.7% due to the decomposition of CaCO3 to CaO and
CO2
31. The TG-DTA analysis for Clay 3 is typical of well-ordered
kaolin with total weight loss of about 12.8%.
32. The TG-DTA analysis for Clay 4 is typical of disordered kaolin
with total weight loss of about 11.0%.
34. 1-Particle Size Analysis
Measurement range of 0.1 to 1000μm.
measure the quantities of particles in each size class in a
sample such as clay, limestone powder, ceramic body
formulation...etc.
Size distribution of the clay particles is important because
the spread of the distribution affects many properties of
the ceramic body slips, plastic forming bodies as well as
many dry and fired ceramic body properties.
35. 2-Fired Properties
Fired shrinkage
Determine the size of the finished product.
If the shrinkage is too large or it is allowed to occur too
rapidly, cracking or distortion of the product.
The fired shrinkage of the clay provides information on the
variations in the composition of the clay.
36. 2-Fired Properties
Water absorption
The water absorption is determined using the "boiling technique".
The fired specimen was first weighed (Fired Weight).
The specimen was then immersed in boiling water for 2 hours after which they
are left to soak in cool water.
Excess moisture is wiped away from the surface of the specimen and then
weighed (Soaked Weight).
37. 2-Fired Properties
Fired Colour
For fired colour, the values of L, a and b are determined.
Scale L is a measure of lightness, a is a measure of redness
or greenness and b is a measure of yellowness or blueness.
Hunterlab Colourimeter
39. Production Process of Ceramic Tiles
Batching
The batching or proportioning may be done by volume or by mass.
Grinding
The purpose of grinding is to obtain smaller particles out of coarser size ones.
Besides that, it also increases reactivity of materials.
There are essentially two methods of grinding namely the wet and dry grinding
method.
40. Production Process of Ceramic Tiles
Spray drying
the process that converts the body slip obtained from the
mill to a granulate with a size distribution and moisture
content suitable for pressing.
The two most important properties to be controlled are the
moisture content and the size distribution of the granulate
42. Production Process of Ceramic Tiles
Drying of the ceramic tile is carried out between the
pressing stage and the firing process.
Drying is performed automatically and continuously in
vertical or horizontal fast dryers.
Glazes are considered as one of the important materials in
the ceramic industry. They are glasses specially designed
to have thermal expansion to match the ceramic
substrate.
43. Production Process of Ceramic Tiles
Firing
The requirements for successful firing process are:
Proper firing temperature, 750 to 1200°C
Uniform heating and cooling of the ware
An atmosphere free from dust
Sorting
At the sorting stage the products are classified according to the quality.
44. Finished Product Testing
1-Microscopy Analysis
2-Ceramic Tiles Technical Properties
a) Dimension
b) Water Absorption
c) Modulus of Rupture & Bending Strength
d) Surface Abrasion Test
e) Crazing Resistance
f) Chemical and Stain resistance
g) Slip Resistance
45. 1-Microscopy Analysis
The Stereo and Polarizing Microscope are very useful tools for
microscopy analysis.
In the investigation of product failure or defects such as spot-holes,
contaminants, surface dirt, black/ green speck...etc, microscopy
analysis provides clues to the cause of defects so that action may be
taken to solve the problem.
Microstructure analysis of the ceramic body provides important
information in assessing the compactness and sintering of bodies after
firing.
48. 2-Ceramic Tiles Technical Properties
a) Dimension
A planarity tester is used to measure the key dimensional characteristics of the
ceramic tile.
b) Water Absorption
Water absorption is the amount of water that a ceramic tile can absorb under
certain experimental conditions expressed in terms of the percentage by
weight of the dry tile.
c) Modulus of Rupture & Bending Strength
Determines whether the tile is capable of bearing the static or dynamic loads
to which the floor or wall may be subjected to during use.
49. d) Surface Abrasion Test
The resistance of the surface of the tile to the movements of other materials
such as wheels, soles of shoes worn by people walking across the tile surface
or mud, sand...etc that come into contact with it.
e) Crazing Resistance
Refers to hairline cracks on the surface of the glazed tile; the pattern formed
by these fine fissures may be either circular or irregular.
2-Ceramic Tiles Technical Properties
50. f) Chemical and Stain resistance
The behavior of a ceramic surface when it comes into
contact with aggressive chemicals that may react with the
surface itself.
g) Slip Resistance
Slip resistance is the measure of tiled surface slipperiness.
2-Ceramic Tiles Technical Properties
52. Impacts and effects
1-Impact of air emissions
a) Particulate matters
b) Sulfur Oxides
c) Nitrogen Oxides
d) Carbon dioxide
e) Dust
f) Silicon dioxide
g) Kaolin Clay
h) Bentonite Clay
i) Soda ash
2-Impact of Effluents
3-Impact of Solid Wastes
4-Impact on Workplace
