CERAMICS

1
CERAMICS

• Group 8
• Blanco González, José Manuel
• Gómez Rojo, Vidal
• Llorente Pérez, Cristina
• Sanz Moral, Luis Miguel

2
General Process
3
Energy Consumption
4
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)

5
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

6
Emissions to air
7
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

8
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

9
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

10
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.

11
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

12
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

13
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

14
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.

15
Considerations about noise

• Applying measures at the source of the noise
• Enclosure the unit
• Build up noise protection walls
• Double walls
• Vibration insulation
• Use silencers
• Secondary noise protection measures
• 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.

16
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.

17
Best Available Techniques

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

18
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.

19
Best Available Techniques

• BAT is to reduce energy
• 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.
• BAT is to reduce diffuse dust emissions
• 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).

20
Best Available Techniques

• 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.

21
Best Available Techniques

• 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.

22
Best Available Techniques

• 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.

23
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

24
1 Radiant tube burners

• Reduction of water vapour levels ? usually
  results in lower emission rates for HF as well as
  of SOx.
• Technicaly difficult?that 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.

25
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.

26
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

27
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.

28
4 Advanced process waste water 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
• Microfiltration.
• treatment of a tributary process waste water
  stream.
• inclusion of existing sedimentation tanks.
• construction of a new central process waste water
  treatment plant.
• separation of rainwater.

29
4 Advanced process waste water management
withintegrated 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.

30
4 Advanced process waste water management
withintegrated 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.

31
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