Ceramics

CERAMICS
Group 8
Blanco Gonzlez, Jos Manuel
Gmez Rojo, Vidal
Llorente Prez, Cristina
Sanz Moral, Luis Miguel
General Process
Energy Consumption
PROCESS
ENERGY
Kiln firing
Drying of intermediates Intensive Energy (almost natural gas, LPG and fuel)
Shaped ware
Plant
Electrical Energy
Machinery
On-site transportation
Diesel fuel
Water Consumption
Water is used in all ceramic processes.
It can be used:
As
a raw material
For the body and its preparation (low quality water)

For glazes (good quality water)
As
a washing fluid (good quality water)

As a cooling medium (good quality water)
Emissions to air
Significant emissions to air arise in the
firing process
Emissions vary:
From
site to site depending on the different

clay raw materials (geological and
geographical variations)
From country to country
Emissions to air
Raw Materials Consumption
There are a number of mineral species called clay

minerals, but the most important are:
Kaolinite
Montmorillonite
Halloysite
Advanced ceramic products:
contain only a small fraction of clay or none at all

Based on the following materials:
Oxides
Carbides
Nitrides
Borides
Other metal ions
Techniques to consider the

determination of BAT
At this point, we consider the techniques that

have potential for achieving a high level of
environmental protection
Management systems, process-integrated and
end of pipe measures are included
Other procedures:
Re-use of materials and energy
Prevention and control
Minimisation and recycling
Principal techniques to consider

The principal techniques to consider are in the following
fields:
Reduction
of energy consumption
Emissions of dusts
Gaseous compounds
Process waste water
Process losses or waste
Noise
Reduction of energy consumption

We can reduce energy by the following ways:
Improved design of kilns and dryers.
Recovery of excess heat from kilns.
Cogeneration/Combined heat and power plants
Substitution of HFO and SF by LEF.
Modification of ceramic bodies.
Emissions of dusts
It include techniques and measures to
prevent diffuse and channeled emissions:
Measures
Separation/filter
systems:
Centrifugal separators
Filters: bas or lamellar
Wet dust separators
Electrostatic precipitators
Gaseous compounds
- Is very important to reduce the input of pollutant
precursors:
Oxides of sulphur
Oxides of nitrogen
Inorganic chlorine compounds
Inorganic fluorine compounds
VOCS
- Addition of Calcium rich additives

- Process optimization, an example is: Reduction of vapour
water levels in the kiln gases
- Sorption plants (adsorbers and absorbers)
- Afterburning
Process waste water

Water has in our case a lot of uses:
raw material
a scrubing agent
a heat exchange vehicule
a cleaning agent
Objetive is to reduce the use of process water.

To reach these, process optimisation measures and
process waste water treatment systems are employed
Process losses or waste

We have two methods where we can improve
the process of manufacturing ceramics:
Sludge arising in the manufacture of ceramic products.

This could be recycling systems or re-use in other products
Solid process looses/ solid waste

This solid process looses can be re-use as raw material.
Considerations about noise

Applying measures at the source of the noise:
o
o
o
o
o
Enclosure the unit

Build up noise protection walls
Double walls
Vibration insulation
Use silencers
Secondary noise protection measures:

o
o
Thicker walls
Sound insulation of the windows
Obviously also gates and windows have to be closed

and cautiously driving reduces the noise emissions.
And last, there is a time-limiting of noise intensive work.
Best Available Techniques
Best Available Techniques for a specific

installation will usually be the use of one
individual or a combination of the techniques.
BAT AEL does not define and suggest

emission limit values (ELVs) because they
are related to installations.

Best Available Techniques can be divided
in two groups:
GENERIC
SECTOR
Best Available Techniques.
SPECIFIC Best Available

Techniques.

GENERIC Best Available Techniques refer to the
following areas:
Environmental management.
Energy.
Dust emissions.
Gaseous compounds.
Process waste water (emissions and consumption).
Sludge.
Solid process losses/solid waste.
Noise.
BAT are defined for each of these areas.
BAT is to reduce energy:
BAT is to reduce diffuse dust emissions:
Improved design of kilns and dryers.

Recovery of excess heat from kilns.
Applying a fuel switch in the kiln firing process.
Modification of ceramic bodies.
Reduce primary energy consumption by applying cogeneration/combined heat and
power plants.
Measures for dusty operations.

Bulk storage area measures.
BAT is to reduce the emissions of gaseous compounds:
Reducing the input of pollutant precursors.

Heating curve optimisation.
Cascade-type packed bed adsorbers.
Dry flue-gas cleaning with a filter (bag filter or electrostatic precipitator).
BAT is to reduce solid process losses/solid waste:
Feedback of unmixed raw materials.

Feedback of broken ware into the manufacturing process.
Use of solid process losses in other industries.
Electronic controlling of firing.
Applying optimised setting.
BAT is to reduce noise:
Enclosure of units.
Vibration insulation of units.
Using silencers and slow rotating fans.
Situating windows, gates and noisy units away from neighbours.
Sound insulation of windows and walls.
Closing windows and gates.
Carrying out noisy (outdoor) activities only during the day.
Good maintenance of the plant.

SECTOR SPECIFIC Best Available Techniques refer
to the following areas:
Bricks and roof tiles.
Vitrified clay pipes.
Refractory products.
Expanded clay aggregates.
Wall and floor tiles.
Table- and ornamental ware (household ceramics).
Technical ceramics.
Sanitaryware.
Inorganic bonded abrasives.
Of the same way, BAT are defined for each of these areas.
BAT is to reduce the emissions of gaseous compounds by addition of calcium

rich additives, if the quality of the end-product is not affected.
BAT is to reduce the emissions of volatile organic compounds by applying

activated carbon filters or thermal afterburning either in a one or a three chamber
thermoreactor.
BAT is to reduce channelled dust emissions by applying bag filters, sintered

lamellar filters, electrostatic precipitators or wet dust separators.
BAT is to reduce the amount of solid process losses/solid waste by applying one
individual or a combination of the following measures:
Replacing plaster moulds by polymer moulds.

Replacing plaster moulds by metal moulds.
Us of vacuum plaster mixers.
Re-use of used plaster moulds in other industries.
Emerging techniques for ceramic

manufacturing
1
Radiant tube burners

2 Microwave assisted firing and microwave
dryers
3 New type of drying system for refractory
products
4 Advanced process waste water
management with integrated glaze recovery
5 Lead-free glazing of high quality table
porcelain
1 Radiant tube burners

Reduction of water vapour levels usually
results in lower emission rates for HF as well as
of SOx.
Technicaly difficultthat water is produced by
the fossi fuels used tohead the kiln.
Solution radiant-tube burners
Heat transfer is carried by thermal radiation.
Applied in roller hearth kilns and shuttle kilns, not
yet proven for tunnel kilns.
2 Microwave assisted firing and

microwave dryers
Heat transfer from the outside to the middle of

the setting and into the centre of individual bricks
is difficult. Temperature gradients can lead to
thermal stresses and damaged products
Solution; microwave energy heats the product
directly including the centre of the units.
microwave energy has been used in
combination with conventional heating such as
gas or electrical energy.
2 Microwave assisted firing and

microwave dryers
Benefits
minimisation of thermal stresses throughout
the firing cycle
reduction of solid process losses/solid waste
reduced emissions based upon less energy
consumption and higher production output
can also be used for drying ceramic ware
3 New type of drying system for

refractory products
The drying of large size refractory building

components is very time consuming and energy
intensive.
By placing heat resistant stainless steel foils or
carbon fibres as the heating element As drying
takes place from the inside out, the water
moves in the same direction as the temperature
front. This reduces drying times considerably
and reduces the energy requirement even 90%.

management with integrated
glaze recovery
An innovative model waste water treatment system
reductions in pollutants and savings in the
manufacture.
The new process waste water system has five modules:
1.
Microfiltration.
2.
treatment of a tributary process waste water stream.
3.
inclusion of existing sedimentation tanks.
4.
construction of a new central process waste water
treatment plant.
5.
separation of rainwater.

management with
integrated glaze recovery
Cost advantages
reduction of personnel costs to 20 % of the
original number of staff required through
automation
reduction of energy costs
reduction in chemical additives
recovery of re-usable glaze
reduction of landfill costs.

management with
integrated glaze recovery
Potential disadvantages:
energy costs for the filtration technology
incorrect design of the microfiltration plant
long phase of research into the use of recovered
glaze
high technical competence is necessary
regarding the overall system
redundancy measures have to be taken into
account in the planning phase.
5 Lead-free glazing of high

quality table porcelain
Lead glazes have been used in the past mainly
for high quality table porcelain.
lead-free glaze formulations based on alkali
boron silicates have been developed by a
tableware producer.annual savings in lead
oxide of 60 tonnes. A higher energy requirement
is needed for the treatment and recovery of
process waste water

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CERAMICS

For the body and its preparation (low quality water)

a washing fluid (good quality water)

site to site depending on the different

Raw Materials Consumption

There are a number of mineral species called clay

Advanced ceramic products:

contain only a small fraction of clay or none at all

Techniques to consider the

At this point, we consider the techniques that

Principal techniques to consider

Reduction of energy consumption

- Addition of Calcium rich additives

Process waste water

Objetive is to reduce the use of process water.

Process losses or waste

Sludge arising in the manufacture of ceramic products.

Solid process looses/ solid waste

Considerations about noise

Enclosure the unit

Secondary noise protection measures:

Obviously also gates and windows have to be closed

Best Available Techniques

Best Available Techniques for a specific

BAT AEL does not define and suggest

Best Available Techniques

Best Available Techniques.

SPECIFIC Best Available

Best Available Techniques

Best Available Techniques

BAT is to reduce energy:

BAT is to reduce diffuse dust emissions:

Improved design of kilns and dryers.

Measures for dusty operations.

BAT is to reduce the emissions of gaseous compounds:

Reducing the input of pollutant precursors.

Best Available Techniques

BAT is to reduce solid process losses/solid waste:

Feedback of unmixed raw materials.

BAT is to reduce noise:

Best Available Techniques

Best Available Techniques

BAT is to reduce the emissions of gaseous compounds by addition of calcium

BAT is to reduce the emissions of volatile organic compounds by applying

BAT is to reduce channelled dust emissions by applying bag filters, sintered

Replacing plaster moulds by polymer moulds.

Emerging techniques for ceramic

Radiant tube burners

1 Radiant tube burners

2 Microwave assisted firing and

Heat transfer from the outside to the middle of

2 Microwave assisted firing and

3 New type of drying system for

The drying of large size refractory building

4 Advanced process waste water

4 Advanced process waste water

4 Advanced process waste water

5 Lead-free glazing of high

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