Edificio EXPO, c/ Inca Garcilaso s/n, E-41092 Sevilla - Spain Telephone: direct line (+34-95) 4488-284, switchboard 4488-318. Fax: 4488-426. Internet: http://eippcb.jrc.es; Email: JRC-IPTS-EIPPCB@cec.eu.int

EUROPEAN COMMISSION DIRECTORATE-GENERAL JRC JOINT RESEARCH CENTRE Institute for Prospective Technological Studies Sustainability in Industry, Energy and Transport European IPPC Bureau

Integrated Pollution Prevention and Control

Draft Reference Document on Best Available Techniques in the Ceramic

Manufacturing Industry

Draft June 2005

This document is one of a series of foreseen documents as below (at the time of writing, not all documents have been drafted):

BREF full title BREF code

Reference Document on Best Available Techniques for Intensive Rearing of Poultry and Pigs ILF

Reference Document on the General Principles of Monitoring MON

Reference Document on Best Available Techniques for the Tanning of Hides and Skins TAN

Reference Document on Best Available Techniques in the Glass Manufacturing Industry GLS

Reference Document on Best Available Techniques in the Pulp and Paper Industry PP

Reference Document on Best Available Techniques on the Production of Iron and Steel I&S

Reference Document on Best Available Techniques in the Cement and Lime Manufacturing Industries CL

Reference Document on the Application of Best Available Techniques to Industrial Cooling Systems CV

Reference Document on Best Available Techniques in the Chlor-Alkali Manufacturing Industry CAK

Reference Document on Best Available Techniques in the Ferrous Metals Processing Industry FMP

Reference Document on Best Available Techniques in the Non Ferrous Metals Industries NFM

Reference Document on Best Available Techniques for the Textiles Industry TXT

Reference Document on Best Available Techniques for Mineral Oil and Gas Refineries REF

Reference Document on Best Available Techniques in the Large Volume Organic Chemical Industry LVOC

Reference Document on Best Available Techniques in Common Waste Water and Waste Gas Treatment/Management Systems in the Chemical Sector CWW

Reference Document on Best Available Techniques in the Food, Drink and Milk Industry FM

Reference Document on Best Available Techniques in the Smitheries and Foundries Industry SF

Reference Document on Best Available Techniques on Emissions from Storage ESB

Reference Document on Economics and Cross-Media Effects ECM

Reference Document on Best Available Techniques for Large Combustion Plants LCP

Reference Document on Best Available Techniques in the Slaughterhouses and Animals By-products Industries

SA

Reference Document on Best Available Techniques for Management of Tailings and Waste-Rock in Mining Activities MTWR

Reference Document on Best Available Techniques for the Surface Treatment of Metals STM

Reference Document on Best Available Techniques for the Waste Treatments Industries WT

Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals (Ammonia, Acids and Fertilisers) LVIC-AAF

Reference Document on Best Available Techniques for Waste Incineration WI

Reference Document on Best Available Techniques for the Production of Polymers POL

Reference Document on Energy Efficiency Techniques ENE

Reference Document on Best Available Techniques for the Manufacture of Organic Fine Chemicals OFC

Reference Document on Best Available Techniques for the Production of Speciality Inorganic Chemicals SIC

Reference Document on Best Available Techniques for Surface Treatment Using Solvents STS

Reference Document on Best Available Techniques for the Manufacture of Large Volume Inorganic Chemicals (Solids and Others) LVIC-S

Reference Document on Best Available Techniques in the Ceramic Manufacturing Industry CER

Executive Summary

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EXECUTIVE SUMMARY

Preface

MB/EIPPCB/CER_Draft_2 Version June 2005 iii

PREFACE

1. Status of this document

Unless otherwise stated, references to the Directive in this document means the Council Directive 96/61/EC on integrated pollution prevention and control. As the Directive applies without prejudice to Community provisions on health and safety at the workplace, so does this document. This document is a working draft of the European IPPC Bureau. It is not an official publication of the European Communities and does not necessarily reflect the position of the European Commission. 2. Relevant legal obligations of the IPPC Directive and the definition of BAT In order to help the reader understand the legal context in which this document has been drafted, some of the most relevant provisions of the IPPC Directive, including the definition of the term best available techniques, are described in this preface. This description is inevitably incomplete and is given for information only. It has no legal value and does not in any way alter or prejudice the actual provisions of the Directive. The purpose of the Directive is to achieve integrated prevention and control of pollution arising from the activities listed in its Annex I, leading to a high level of protection of the environment as a whole. The legal basis of the Directive relates to environmental protection. Its implementation should also take account of other Community objectives such as the competitiveness of the Communitys industry thereby contributing to sustainable development. More specifically, it provides for a permitting system for certain categories of industrial installations requiring both operators and regulators to take an integrated, overall look at the polluting and consuming potential of the installation. The overall aim of such an integrated approach must be to improve the management and control of industrial processes so as to ensure a high level of protection for the environment as a whole. Central to this approach is the general principle given in Article 3 that operators should take all appropriate preventative measures against pollution, in particular through the application of best available techniques enabling them to improve their environmental performance. The term best available techniques is defined in Article 2(11) of the Directive as the most effective and advanced stage in the development of activities and their methods of operation which indicate the practical suitability of particular techniques for providing in principle the basis for emission limit values designed to prevent and, where that is not practicable, generally to reduce emissions and the impact on the environment as a whole. Article 2(11) goes on to clarify further this definition as follows: techniques includes both the technology used and the way in which the installation is designed, built, maintained, operated and decommissioned; available techniques are those developed on a scale which allows implementation in the relevant industrial sector, under economically and technically viable conditions, taking into consideration the costs and advantages, whether or not the techniques are used or produced inside the Member State in question, as long as they are reasonably accessible to the operator; best means most effective in achieving a high general level of protection of the environment as a whole.

Preface

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Furthermore, Annex IV of the Directive contains a list of considerations to be taken into account generally or in specific cases when determining best available techniques... bearing in mind the likely costs and benefits of a measure and the principles of precaution and prevention. These considerations include the information published by the Commission pursuant to Article 16(2). Competent authorities responsible for issuing permits are required to take account of the general principles set out in Article 3 when determining the conditions of the permit. These conditions must include emission limit values, supplemented or replaced where appropriate by equivalent parameters or technical measures. According to Article 9(4) of the Directive, these emission limit values, equivalent parameters and technical measures must, without prejudice to compliance with environmental quality standards, be based on the best available techniques, without prescribing the use of any technique or specific technology, but taking into account the technical characteristics of the installation concerned, its geographical location and the local environmental conditions. In all circumstances, the conditions of the permit must include provisions on the minimisation of long-distance or transboundary pollution and must ensure a high level of protection for the environment as a whole. Member States have the obligation, according to Article 11 of the Directive, to ensure that competent authorities follow or are informed of developments in best available techniques. 3. Objective of this Document Article 16(2) of the Directive requires the Commission to organise an exchange of information between Member States and the industries concerned on best available techniques, associated monitoring and developments in them, and to publish the results of the exchange. The purpose of the information exchange is given in recital 25 of the Directive, which states that the development and exchange of information at Community level about best available techniques will help to redress the technological imbalances in the Community, will promote the worldwide dissemination of limit values and techniques used in the Community and will help the Member States in the efficient implementation of this Directive. The Commission (Environment DG) established an information exchange forum (IEF) to assist the work under Article 16(2) and a number of technical working groups have been established under the umbrella of the IEF. Both IEF and the technical working groups include representation from Member States and industry as required in Article 16(2). The aim of this series of documents is to reflect accurately the exchange of information which has taken place as required by Article 16(2) and to provide reference information for the permitting authority to take into account when determining permit conditions. By providing relevant information concerning best available techniques, these documents should act as valuable tools to drive environmental performance. 4. Information Sources This document represents a summary of information collected from a number of sources, including in particular the expertise of the groups established to assist the Commission in its work, and verified by the Commission services. All contributions are gratefully acknowledged. 5. How to understand and use this document The information provided in this document is intended to be used as an input to the determination of BAT in specific cases. When determining BAT and setting BAT-based permit conditions, account should always be taken of the overall goal to achieve a high level of protection for the environment as a whole.

Preface

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The rest of this section describes the type of information that is provided in each section of this document. Chapters 1 and 2 provide general information on the ceramic manufacturing industry and on the industrial processes used within this industry. Chapter 3 provides data and information concerning current emission and consumption levels reflecting the situation in existing installations at the time of writing. Chapter 4 describes in more detail the emission reduction and other techniques that are considered to be most relevant for determining BAT and BAT-based permit conditions. This information includes the consumption and emission levels considered achievable by using the technique, some idea of the costs and the cross-media issues associated with the technique, and the extent to which the technique is applicable to the range of installations requiring IPPC permits, for example new, existing, large or small installations. Also the applicability of a technique in the different sectors of the ceramic industry is taken into consideration. Techniques that are generally seen as obsolete are not included. Chapter 5 presents the techniques and the emission and consumption levels that are considered to be compatible with BAT in a general sense. The purpose is thus to provide general indications regarding the emission and consumption levels that can be considered as an appropriate reference point to assist in the determination of BAT-based permit conditions or for the establishment of general binding rules under Article 9(8). It should be stressed, however, that this document does not propose emission limit values. The determination of appropriate permit conditions will involve taking account of local, site-specific factors such as the technical characteristics of the installation concerned, its geographical location and the local environmental conditions. In the case of existing installations, the economic and technical viability of upgrading them also needs to be taken into account. Even the single objective of ensuring a high level of protection for the environment as a whole will often involve making trade-off judgements between different types of environmental impact, and these judgements will often be influenced by local considerations. Although an attempt is made to address some of these issues, it is not possible for them to be considered fully in this document. The techniques and levels presented in Chapter 5 will therefore not necessarily be appropriate for all installations. On the other hand, the obligation to ensure a high level of environmental protection including the minimisation of long-distance or transboundary pollution implies that permit conditions cannot be set on the basis of purely local considerations. It is therefore of the utmost importance that the information contained in this document is fully taken into account by permitting authorities. Since the best available techniques change over time, this document will be reviewed and updated as appropriate. All comments and suggestions should be made to the European IPPC Bureau at the Institute for Prospective Technological Studies at the following address:

Edificio Expo, c/ Inca Garcilaso, s/n, E-41092 Sevilla, Spain Telephone: +34 95 4488 284 Fax: +34 95 4488 426 e-mail: JRC-IPTS-EIPPCB@cec.eu.intInternet: http://eippcb.jrc.es

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Best Available Techniques Reference Document on Ceramic Manufacturing

EXECUTIVE SUMMARY.........................................................................................................................I PREFACE................................................................................................................................................ III SCOPE ...................................................................................................................................................XIX 1 GENERAL INFORMATION ON CERAMIC MANUFACTURING ........................................ 21

1.1 Historical origins...................................................................................................................... 21 1.2 Characteristics of ceramics....................................................................................................... 21 1.3 Geographical distribution and general economic considerations ............................................. 23 1.4 Key environmental issues......................................................................................................... 23 1.5 Ceramics groups and sectors .................................................................................................... 24

1.5.1 Coarse ceramics ............................................................................................................. 25 1.5.1.1 Bricks and roof tiles ............................................................................................... 25 1.5.1.2 Vitrified clay pipes ................................................................................................. 26 1.5.1.3 Refractory products ................................................................................................ 26 1.5.1.4 Expanded clay aggregates ...................................................................................... 27

1.5.2 Fine ceramics ................................................................................................................. 28 1.5.2.1 Wall and floor tiles................................................................................................. 28 1.5.2.2 Table- and ornamentalware (household ceramics)................................................. 30 1.5.2.3 Sanitaryware........................................................................................................... 30 1.5.2.4 Technical ceramics................................................................................................. 31 1.5.2.5 Inorganic bonded abrasives .................................................................................... 31

2 APPLIED PROCESSES AND TECHNIQUES IN CERAMIC MANUFACTURING ............. 33 2.1 Raw materials........................................................................................................................... 33 2.2 General production process description ................................................................................... 34

2.2.1 Storage and transport of raw materials........................................................................... 34 2.2.2 Preparation of raw materials .......................................................................................... 35

2.2.2.1 Pre-drying............................................................................................................... 35 2.2.2.2 Pre-blending ........................................................................................................... 35 2.2.2.3 Weathering/souring ................................................................................................ 35 2.2.2.4 Primary and secondary crushing, grinding and screening...................................... 35 2.2.2.5 Dry or wet milling (grinding)................................................................................. 36 2.2.2.6 Dry screening/air classification.............................................................................. 36 2.2.2.7 Spray drying........................................................................................................... 36 2.2.2.8 Calcining ................................................................................................................ 36 2.2.2.9 Synthetic base materials ......................................................................................... 37 2.2.2.10 Frits and glazes, glaze preparation ......................................................................... 37

2.2.3 Component mixing......................................................................................................... 37 2.2.3.1 General ................................................................................................................... 37 2.2.3.2 Continuous mixers ................................................................................................. 38 2.2.3.3 Batch mixers .......................................................................................................... 38

2.2.4 Shaping/forming of ware ............................................................................................... 38 2.2.4.1 General ................................................................................................................... 38 2.2.4.2 Pressing .................................................................................................................. 39

2.2.4.2.1 Mechanical pressing ....................................................................................... 39 2.2.4.2.2 Hydraulic pressing.......................................................................................... 39 2.2.4.2.3 Impact pressing .............................................................................................. 39 2.2.4.2.4 Friction pressing............................................................................................. 39 2.2.4.2.5 Isostatic pressing ............................................................................................ 39

2.2.4.3 Extrusion ................................................................................................................ 39 2.2.4.4 Moulding................................................................................................................ 40 2.2.4.5 Slip casting............................................................................................................. 40 2.2.4.6 Fusion casting ........................................................................................................ 40

2.2.5 Drying of ceramic products............................................................................................ 40 2.2.5.1 General ................................................................................................................... 40 2.2.5.2 Hot floor dryers ...................................................................................................... 41 2.2.5.3 Chamber dryers (intermittent) ................................................................................ 41 2.2.5.4 Tunnel dryers (continuous) .................................................................................... 41

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2.2.5.5 Vertical basket dryers...........................................................................................42 2.2.5.6 Horizontal multi-deck roller dryers ........................................................................42 2.2.5.7 Dehumidifying dryers .............................................................................................42 2.2.5.8 Infrared and microwave dryers ...............................................................................42

2.2.6 Surface treatment and decoration of ceramic products...................................................42 2.2.6.1 Texturing of clay products......................................................................................42 2.2.6.2 Applied facings.......................................................................................................43 2.2.6.3 Engobing, glazing and other decorating techniques ...............................................43

2.2.7 Firing ..............................................................................................................................44 2.2.7.1 Aims of firing .........................................................................................................44 2.2.7.2 Physico-chemical changes during firing.................................................................44 2.2.7.3 Intermittent (periodic) kilns ....................................................................................45 2.2.7.4 Continuous kilns .....................................................................................................46

2.2.7.4.1 Chamber (Hoffmann) kilns .............................................................................46 2.2.7.4.2 Tunnel kilns ....................................................................................................46 2.2.7.4.3 Roller hearth kilns...........................................................................................48 2.2.7.4.4 Sliding bat kilns ..............................................................................................48

2.2.7.5 Clamp firing............................................................................................................48 2.2.7.6 Rotary kilns.............................................................................................................48 2.2.7.7 Fluidised beds .........................................................................................................49 2.2.7.8 Cooling stage heat recovery....................................................................................49

2.2.8 Subsequent treatment (product finishing).......................................................................49 2.2.8.1 Machining (grinding, drilling, sawing) ...................................................................49

2.2.8.1.1 Wet grinding ...................................................................................................49 2.2.8.1.2 Dry grinding....................................................................................................49 2.2.8.1.3 Drilling............................................................................................................49 2.2.8.1.4 Sawing ............................................................................................................50

2.2.8.2 Polishing .................................................................................................................50 2.2.8.3 Carbon enrichment (refractory products)................................................................50 2.2.8.4 Tumbling of facing bricks ......................................................................................50

2.2.9 Addition of auxiliary materials .......................................................................................51 2.2.9.1 Jointing materials (pipes)........................................................................................51 2.2.9.2 Silicones/water repellents .......................................................................................51 2.2.9.3 Insulation materials.................................................................................................51 2.2.9.4 Carding and plating (refractory bricks)...................................................................51 2.2.9.5 Adhesives................................................................................................................51 2.2.9.6 Final assembly ........................................................................................................51

2.2.10 Sorting, packaging and storage.......................................................................................51 2.2.11 Supply and disposal (off-gas treatment and process waste water treatment) facilities ...52 2.2.12 Recycling in the ceramic industry ..................................................................................52 2.2.13 General process flow diagram showing different processing paths................................53

2.3 Description of techniques for the manufacture of coarse ceramics...........................................55 2.3.1 Bricks and roof tiles........................................................................................................55

2.3.1.1 Raw materials .........................................................................................................56 2.3.1.2 Preparation of raw materials ...................................................................................60 2.3.1.3 Shaping ...................................................................................................................60 2.3.1.4 Drying, glazing and engobing.................................................................................61 2.3.1.5 Firing ......................................................................................................................61 2.3.1.6 Subsequent treatment..............................................................................................63 2.3.1.7 Input and output flows in the manufacture of bricks and roof tiles ........................64

2.3.2 Vitrified clay pipes .........................................................................................................64 2.3.2.1 Raw materials .........................................................................................................65 2.3.2.2 Preparation of raw materials ...................................................................................67 2.3.2.3 Shaping ...................................................................................................................67 2.3.2.4 Drying and glazing .................................................................................................67 2.3.2.5 Firing ......................................................................................................................67 2.3.2.6 Subsequent treatment..............................................................................................68 2.3.2.7 Input and output flows in the manufacture of vitrified clay pipes ..........................68

2.3.3 Refractory products ........................................................................................................69 2.3.3.1 Raw materials .........................................................................................................70 2.3.3.2 Preparation of raw materials ...................................................................................71 2.3.3.3 Shaping ...................................................................................................................71

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2.3.3.4 Drying .................................................................................................................... 72 2.3.3.5 Firing...................................................................................................................... 72 2.3.3.6 Subsequent treatment ............................................................................................. 73 2.3.3.7 Special procedures ................................................................................................. 73 2.3.3.8 Input and output flows in the manufacture of refractory products ......................... 74

2.3.4 Expanded clay aggregates .............................................................................................. 74 2.3.4.1 Raw materials, additives and auxiliary agents ....................................................... 76 2.3.4.2 General system and process technology................................................................. 79

2.3.4.2.1 Shaping........................................................................................................... 79 2.3.4.2.2 Thermal process technology........................................................................... 79 2.3.4.2.3 Chemical reaction during expansion .............................................................. 80 2.3.4.2.4 Subsequent sieving and crushing.................................................................... 81

2.3.4.3 Specific techniques for the manufacture of expanded clay aggregates .................. 81 2.3.4.3.1 Leca technique................................................................................................ 81 2.3.4.3.2 Liapor technique............................................................................................. 82

2.3.4.4 Input and output flows in the manufacture of expanded clay aggregates............... 83 2.4 Description of techniques for the manufacture of fine ceramics .............................................. 84

2.4.1 Wall and floor tiles......................................................................................................... 84 2.4.1.1 Raw materials......................................................................................................... 85 2.4.1.2 Preparation of raw materials .................................................................................. 86 2.4.1.3 Shaping................................................................................................................... 86 2.4.1.4 Drying .................................................................................................................... 86 2.4.1.5 Firing and glazing .................................................................................................. 87 2.4.1.6 Subsequent treatment ............................................................................................. 87 2.4.1.7 Input and output flows in the manufacture of wall and floor tiles.......................... 88

2.4.2 Table- and ornamentalware (household ceramics)......................................................... 88 2.4.2.1 Raw materials......................................................................................................... 89 2.4.2.2 Preparation of raw materials .................................................................................. 90 2.4.2.3 Shaping................................................................................................................... 91 2.4.2.4 Drying .................................................................................................................... 92 2.4.2.5 Firing, glazing and decoration................................................................................ 92 2.4.2.6 Subsequent treatment ............................................................................................. 94 2.4.2.7 Input and output flows in the manufacture of household ceramics ........................ 95

2.4.3 Sanitaryware .................................................................................................................. 96 2.4.3.1 Raw materials......................................................................................................... 96 2.4.3.2 Preparation of raw materials .................................................................................. 97 2.4.3.3 Shaping................................................................................................................... 97 2.4.3.4 Drying and glazing................................................................................................. 97 2.4.3.5 Firing...................................................................................................................... 98 2.4.3.6 Subsequent treatment ............................................................................................. 99 2.4.3.7 Input and output flows in the manufacture of sanitaryware ................................... 99

2.4.4 Technical ceramics....................................................................................................... 100 2.4.4.1 Raw materials....................................................................................................... 101 2.4.4.2 Preparation of raw materials ................................................................................ 102 2.4.4.3 Shaping................................................................................................................. 103 2.4.4.4 Machining ............................................................................................................ 104 2.4.4.5 Glazing, engobing and metallisation .................................................................... 105 2.4.4.6 Drying, burning out and pre-firing ....................................................................... 106 2.4.4.7 Firing/sintering..................................................................................................... 107 2.4.4.8 Subsequent treatment ........................................................................................... 108 2.4.4.9 Input and output flows in the manufacture of technical ceramics ........................ 108

2.4.5 Inorganic bonded abrasives.......................................................................................... 109 2.4.5.1 Raw materials....................................................................................................... 109 2.4.5.2 Preparation of raw materials ................................................................................ 109 2.4.5.3 Shaping................................................................................................................. 110 2.4.5.4 Drying .................................................................................................................. 110 2.4.5.5 Firing.................................................................................................................... 110 2.4.5.6 Subsequent treatment ........................................................................................... 110 2.4.5.7 Input and output flows in the manufacture of inorganic bonded abrasives .......... 110

3 CURRENT EMISSION AND CONSUMPTION LEVELS ....................................................... 113 3.1 Emissions general considerations........................................................................................ 113

3.1.1 Emissions to air............................................................................................................ 113

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3.1.1.1 Dust (particulate matter) .......................................................................................113 3.1.1.2 Gaseous emissions ................................................................................................113

3.1.1.2.1 Sulphur dioxide and other sulphur compounds.............................................113 3.1.1.2.2 Oxides of nitrogen and other nitrogen compounds .......................................113 3.1.1.2.3 Carbon monoxide (and carbon dioxide)........................................................113 3.1.1.2.4 Volatile organic compounds (VOCs)............................................................114 3.1.1.2.5 Metals and their compounds .........................................................................114 3.1.1.2.6 Chlorine and its compounds..........................................................................114 3.1.1.2.7 Fluorine and its compounds ..........................................................................114

3.1.2 Emissions to water........................................................................................................115 3.1.3 Process losses (waste)...................................................................................................116 3.1.4 Emissions of noise ........................................................................................................116 3.1.5 Possible emission sources and emission paths .............................................................117

3.2 Consumption general considerations ...................................................................................118 3.2.1 Energy consumption .....................................................................................................118 3.2.2 Water consumption.......................................................................................................118 3.2.3 Raw materials consumption..........................................................................................118

3.3 Presentation of emission and consumption data .....................................................................118 3.3.1 Coarse ceramics............................................................................................................119

3.3.1.1 Bricks and roof tiles..............................................................................................119 3.3.1.1.1 Emission data................................................................................................119 3.3.1.1.2 Consumption data .........................................................................................125

3.3.1.2 Vitrified clay pipes ...............................................................................................127 3.3.1.2.1 Emission data................................................................................................127 3.3.1.2.2 Consumption data .........................................................................................129

3.3.1.3 Refractory products ..............................................................................................130 3.3.1.3.1 Emission data................................................................................................130 3.3.1.3.2 Consumption data .........................................................................................132

3.3.1.4 Expanded clay aggregates.....................................................................................134 3.3.1.4.1 Emission data................................................................................................134 3.3.1.4.2 Consumption data .........................................................................................136

3.3.2 Fine ceramics................................................................................................................137 3.3.2.1 Wall and floor tiles ...............................................................................................137

3.3.2.1.1 Emission data................................................................................................137 3.3.2.1.2 Consumption data .........................................................................................140

3.3.2.2 Table- and ornamentalware (household ceramics) ...............................................142 3.3.2.2.1 Emission data................................................................................................142 3.3.2.2.2 Consumption data .........................................................................................146

3.3.2.3 Sanitaryware .........................................................................................................147 3.3.2.3.1 Emission data................................................................................................147 3.3.2.3.2 Consumption data .........................................................................................150

3.3.2.4 Technical ceramics ...............................................................................................151 3.3.2.4.1 Emission data................................................................................................151 3.3.2.4.2 Consumption data .........................................................................................154

3.3.2.5 Inorganic bonded abrasives ..................................................................................155 3.3.2.5.1 Emission data................................................................................................155 3.3.2.5.2 Consumption data .........................................................................................156

4 TECHNIQUES TO CONSIDER IN THE DETERMINATION OF BAT FOR CERAMIC MANUFACTURING .....................................................................................................................157

4.1 Reduction of energy consumption (energy efficiency) ...........................................................159 4.1.1 Improved design of kilns and dryers ............................................................................159 4.1.2 Recovery of excess heat from kilns ..............................................................................160 4.1.3 Cogeneration/combined heat and power plants ............................................................162 4.1.4 Substitution of heavy fuel oil and solid fuels by clean fuels ........................................163 4.1.5 Modification of ceramic bodies ....................................................................................164 4.1.6 Overview on techniques for the reduction of energy consumption ..............................166

4.2 Emissions of dust (particulate matter) ....................................................................................166 4.2.1 Measures for dusty operations ......................................................................................166 4.2.2 Measures for bulk storage areas ...................................................................................167 4.2.3 Separation/filter systems...............................................................................................168

4.2.3.1 Centrifugal separators...........................................................................................168 4.2.3.2 Bag filters .............................................................................................................169

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4.2.3.3 Sintered lamellar filters ........................................................................................ 172 4.2.3.4 Wet dust separators .............................................................................................. 173 4.2.3.5 Electrostatic precipitators (ESP) .......................................................................... 174

4.2.4 Overview on techniques for the reduction of dust (particulate matter) emissions ....... 175 4.3 Gaseous compounds............................................................................................................... 175

4.3.1 Reduction of input of pollutant precursors................................................................... 175 4.3.2 Addition of calcium rich additives ............................................................................... 177 4.3.3 Process optimisation .................................................................................................... 179

4.3.3.1 Optimising the heating curve ............................................................................... 179 4.3.3.2 Reduction of water vapour levels in the kiln gases .............................................. 180 4.3.3.3 Internal carbonisation gas combustion ................................................................. 181 4.3.3.4 Low-NOX burners ................................................................................................ 182

4.3.4 Sorption plants (adsorbers, absorbers) ......................................................................... 182 4.3.4.1 Cascade-type packed bed adsorbers ..................................................................... 183 4.3.4.2 Module adsorber systems ..................................................................................... 186 4.3.4.3 Dry flue-gas cleaning with a filter (bag filter or electrostatic precipitator).......... 187 4.3.4.4 Wet flue-gas cleaning........................................................................................... 190 4.3.4.5 Activated carbon filters ........................................................................................ 192 4.3.4.6 Biological scrubbers............................................................................................. 193

4.3.5 Afterburning................................................................................................................. 194 4.3.5.1 Thermal afterburning in a thermoreactor ............................................................. 194 4.3.5.2 Catalytic afterburning........................................................................................... 196

4.3.6 Overview on techniques for the reduction of gaseous compounds .............................. 198 4.4 Process waste water................................................................................................................ 198

4.4.1 Water used as a raw material ....................................................................................... 198 4.4.2 Water used as a heat exchange vehicle ........................................................................ 199 4.4.3 Water used as a scrubbing agent .................................................................................. 199 4.4.4 Water used as a cleaning agent .................................................................................... 199 4.4.5 Objectives and solutions for the reduction of process waste water (emissions and

consumption)................................................................................................................ 199 4.4.5.1 Process optimisation............................................................................................. 199 4.4.5.2 Systems of process waste water treatment ........................................................... 201

4.4.6 Overview on techniques for the reduction of process waste water (emissions and consumption)................................................................................................................ 203

4.5 Process losses (waste) ............................................................................................................ 204 4.5.1 Sludge arising in the manufacture of ceramic products ............................................... 204

4.5.1.1 Sludge recycling systems ..................................................................................... 204 4.5.1.2 Sludge re-use in other products ............................................................................ 206 4.5.1.3 Overview on techniques for the recycling/re-use of sludge ................................. 206

4.5.2 Solid process losses (solid waste) ................................................................................ 207 4.5.2.1 General considerations concerning re-use of solid process losses as raw materials

.............................................................................................................................. 207 4.5.2.2 General considerations on plaster moulds, firing auxiliaries and broken ware

avoidance/replacement/reduction........................................................................ 208 4.5.2.3 Overview on techniques for the reduction of solid process losses (solid waste).. 209

4.6 General considerations concerning noise ............................................................................... 210 4.6.1 Overview on techniques for the reduction of noise...................................................... 211

4.7 Environmental management tools .......................................................................................... 211 5 BEST AVAILABLE TECHNIQUES FOR CERAMIC MANUFACTURING........................ 221

5.1 Generic Best Available Techniques ....................................................................................... 223 5.1.1 Environmental management......................................................................................... 223 5.1.2 Energy consumption .................................................................................................... 224 5.1.3 Dust emissions ............................................................................................................. 224

5.1.3.1 Diffuse dust emissions ......................................................................................... 224 5.1.3.2 Channelled dust emissions from dusty operations ............................................... 224

5.1.4 Gaseous compounds..................................................................................................... 225 5.1.4.1 Primary measures/techniques ............................................................................... 225 5.1.4.2 Secondary measures/techniques and combination with primary

measures/techniques............................................................................................. 225 5.1.5 Process waste water (emissions and consumption) ...................................................... 226 5.1.6 Sludge .......................................................................................................................... 226 5.1.7 Solid process losses (waste) ......................................................................................... 226

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5.1.8 Noise.............................................................................................................................226 5.2 Sector specific Best Available Techniques.............................................................................227

5.2.1 Energy consumption .....................................................................................................227 5.2.2 Channelled dust emissions............................................................................................227 5.2.3 Volatile organic compounds .........................................................................................227 5.2.4 Re-use of process waste water ......................................................................................227 5.2.5 Re-use of sludge ...........................................................................................................227 5.2.6 Solid process losses (waste) .........................................................................................228

6 EMERGING TECHNIQUES FOR CERAMIC MANUFACTURING.....................................229 6.1 Radiant tube burners ...............................................................................................................229 6.2 Microwave assisted firing and microwave dryers...................................................................230

7 CONCLUDING REMARKS.........................................................................................................231 8 REFERENCES...............................................................................................................................233 9 GLOSSARY....................................................................................................................................235 10 ANNEX 1.........................................................................................................................................241

10.1 Expanded clay aggregates Liapor technique........................................................................241 11 ANNEX 2.........................................................................................................................................248

11.1 Expanded clay aggregates Leca technique...........................................................................248

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List of figures

Figure 1.1: Stages in the manufacture of ceramic products........................................................................ 22 Figure 1.2: Areas of application for expanded clay products in per cent in Germany ............................... 28 Figure 2.1: Ranges of industrial maturing temperatures for different product groups ............................... 45 Figure 2.2: Cross-section of a shuttle kiln.................................................................................................. 46 Figure 2.3: Schematic view of a tunnel kiln............................................................................................... 47 Figure 2.4: Cross-section of a tunnel kiln with a tunnel kiln car................................................................ 47 Figure 2.5: Cross-section of a roller hearth kiln......................................................................................... 48 Figure 2.6: General process flow diagram showing different processing paths ......................................... 54 Figure 2.7: Schematic view of pressed roof tile manufacture .................................................................... 55 Figure 2.8: Schematic view of masonry brick manufacture ....................................................................... 56 Figure 2.9: Distribution of fluoride content in Italian clays ....................................................................... 58 Figure 2.10: Distribution of sulphur content in Italian clays...................................................................... 59 Figure 2.11: Sulphur content in clays......................................................................................................... 59 Figure 2.12: Input and output flows in the manufacture of bricks and roof tiles ....................................... 64 Figure 2.13: Schematic view of the manufacture of vitrified clay pipes.................................................... 65 Figure 2.14: Input and output flows in the manufacture of vitrified clay pipes ......................................... 69 Figure 2.15: Schematic view of the manufacture of basic bricks containing chromium ore...................... 70 Figure 2.16: Input and output flows in the manufacture of refractory products......................................... 74 Figure 2.17: Schematic view of the manufacture of expanded clay aggregates......................................... 76 Figure 2.18: Input and output flows in the manufacture of expanded clay aggregates .............................. 84 Figure 2.19: Schematic view of wall and floor tile manufacturing ............................................................ 85 Figure 2.20: Input and output flows in the manufacture of wall and floor tiles ......................................... 88 Figure 2.21: Schematic view of the manufacture of table porcelain .......................................................... 89 Figure 2.22: Input and output flows in the manufacture of household ceramics........................................ 95 Figure 2.23: Schematic view of the manufacture of sanitaryware ............................................................. 96 Figure 2.24: Input and output flows in the manufacture of sanitaryware................................................... 99 Figure 2.25: Schematic view of an electrical insulator manufacturing process ....................................... 100 Figure 2.26: Schematic view of a ceramic catalyst manufacturing process ............................................. 101 Figure 2.27: Green, white and hard machining in the manufacture of technical ceramics....................... 105 Figure 2.28: Input and output flows in the manufacture of technical ceramics........................................ 108 Figure 2.29: Input and output flows in the manufacture of inorganic bonded abrasives.......................... 111 Figure 3.1: Distribution of released fluoride in the Italian brick and roof tile industry............................ 120 Figure 3.2: Distribution of released chloride in the Italian brick and roof tile industry ........................... 121 Figure 3.3: Sulphur emissions (SOX) in Germany, United Kingdom and Belgium ................................. 121 Figure 3.4: Mass flow example for the manufacture of masonry bricks .................................................. 127 Figure 3.5: Mass flow example for the manufacture of vitrified clay pipes............................................. 130 Figure 3.6: Mass flow example for the manufacture of periclase chromite bricks................................... 133 Figure 3.7: Mass flow example for the manufacture of tableware ........................................................... 147 Figure 3.8: Mass flow example for the manufacture of sanitaryware ...................................................... 151 Figure 4.1: Schematic view of an example of a combined heat recycling system ................................... 161 Figure 4.2: Schematic view of hot air generation using a cogeneration gas engine ................................. 162 Figure 4.3: Schematic view of a bag filter with pressure pulse regeneration ........................................... 170 Figure 4.4: Investment cost examples for filter plants without installation and filter bags ...................... 171 Figure 4.5: Schematic view of a rigid sintered lamellar filter .................................................................. 172 Figure 4.6: Temperature ranges of a temperature curve example for the release of pollutants during the

firing of bricks ................................................................................................................... 179 Figure 4.7: Schematic view of internal carbonisation gas combustion .................................................... 181 Figure 4.8: Illustration of a crossflow cascade adsorber .......................................................................... 183 Figure 4.9: Process diagram of a cascade-type packed bed adsorber with peeling drum......................... 184 Figure 4.10: Schematic view of a honeycomb module adsorber system.................................................. 186 Figure 4.11: Schematic view of dry flue-gas cleaning with a bag filter ................................................... 188 Figure 4.12: Schematic view of dry flue-gas cleaning with an electrostatic precipitator......................... 188 Figure 4.13: Illustration of a wet flue-gas cleaning unit........................................................................... 191 Figure 4.14: Schematic view of a thermal afterburning system (three-chamber system)......................... 195 Figure 4.15: Flue-gas conduction in an external thermal afterburning system ........................................ 195 Figure 4.16: Flow diagram of a process waste water purification plant................................................... 202 Figure 4.17: Schematic view of a sludge recycling installation ............................................................... 204

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Figure 10.1: Manufacture of Liapor LWA, from the example plants in Hallerndorf-Pautzfeld and Tuningen ............................................................................................................................241

Figure 10.2: Primary roll crusher..............................................................................................................242 Figure 10.3: Bowl mill crusher .................................................................................................................243 Figure 10.4: Dish granulator and principle of granulation........................................................................244 Figure 10.5: Flue-gas cleaning system......................................................................................................245 Figure 10.6: Screening unit.......................................................................................................................247 Figure 10.7: Sand crusher .........................................................................................................................248 Figure 11.1: Manufacture of Leca LWA, from the example plant in Lamstedt........................................249

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List of tables

Table 1.1: Ceramics output, sales and employment figures ....................................................................... 23 Table 1.2: Share of used fuels in Germany per sector in 1998................................................................... 24 Table 1.3: The vitrified clay pipes industry in Europe ............................................................................... 26 Table 1.4: EU-15 manufacture of refractory products in 2001/2002 ......................................................... 27 Table 1.5: Simplified classification of ceramic tiles .................................................................................. 29 Table 1.6: Energy consumption per Member State (specific energy consumption in TJ per 1000 tonnes

produced) ............................................................................................................................. 30 Table 1.7: Output of table- and ornamentalware........................................................................................ 30 Table 2.1: Ranges of chemical and mineralogical compositions of clay raw materials applied in the brick

and roof tile industry in different European countries ......................................................... 57 Table 2.2: Mineralogical and chemical composition of clays used in the manufacture of bricks and roof

tiles in Germany................................................................................................................... 58 Table 2.3: Operating data of tunnel kilns ................................................................................................... 62 Table 2.4: Comparison of classic tunnel kilns and fast firing methods (roof tiles) .................................... 62 Table 2.5: Operating data of fast firing tunnel kilns................................................................................... 63 Table 2.6: Mineralogical composition of clay in the manufacture of vitrified clay pipes.......................... 66 Table 2.7: Chemical composition of clay in the manufacture of vitrified clay pipes ................................. 66 Table 2.8: Ranges of operating data of tunnel kilns ................................................................................... 68 Table 2.9: Most used oxides in melting/casting operations........................................................................ 71 Table 2.10: Operating data of periodically operated dryers (chamber dryers) ........................................... 72 Table 2.11: Operating data of two tunnel dryers and a climate controlled dryer ....................................... 72 Table 2.12: Operating data of tunnel kilns used in the refractory industry ................................................ 73 Table 2.13: Operating data of shuttle kilns ................................................................................................ 73 Table 2.14: Chemical composition of expandable raw materials............................................................... 77 Table 2.15: Mineral composition of expandable raw materials ................................................................. 77 Table 2.16: Examples of expansion promoting additives and auxiliary agents.......................................... 78 Table 2.17: Average mineral composition of the raw clay......................................................................... 78 Table 2.18: Average mineral composition of the expansion material (Leca technique) ............................ 78 Table 2.19: Average mineral composition of Lias delta raw clay.............................................................. 78 Table 2.20: Average mineral composition of the expansion material (Liapor technique) ......................... 79 Table 2.21: Average composition of the gases in the hot expansion material............................................ 81 Table 2.22: Operating data of tunnel kilns and roller hearth kilns ............................................................. 87 Table 2.23: Typical ranges of the mineralogical composition of raw materials for the manufacture of

household ceramics.............................................................................................................. 90 Table 2.24: Typical ranges of the chemical composition of raw materials for the manufacture of

household ceramics.............................................................................................................. 90 Table 2.25: Operating data of a shuttle kiln ............................................................................................... 92 Table 2.26: Operating data of tunnel kilns ................................................................................................. 93 Table 2.27: On-glaze decoration operating data......................................................................................... 94 Table 2.28: In-glaze and under-glaze decoration operating data................................................................ 94 Table 2.29: Operating data of periodically operated dryers (chamber dryers) ........................................... 98 Table 2.30: Operating data of tunnel kilns ................................................................................................. 98 Table 2.31: Operating data of shuttle kilns ................................................................................................ 98 Table 2.32: Sintering temperatures for technical ceramic materials ........................................................ 107 Table 3.1: Overview on possible emission sources and emission paths in the ceramic industry ............. 117 Table 3.2: Emission ranges of raw flue-gases from brick and roof tiles manufacturing processes .......... 120 Table 3.3: Operating data of raw gas with various fuels .......................................................................... 122 Table 3.4: Raw gas values with various pore-forming agents.................................................................. 122 Table 3.5: Average clean gas values (porous clay blocks) ....................................................................... 122 Table 3.6: Product related emission factors (porous clay blocks) ............................................................ 123 Table 3.7: Clean gas concentrations of masonry brick plants .................................................................. 124 Table 3.8: Clean gas concentrations of klinker brick plants and roof tile plants...................................... 124 Table 3.9: Energy consumption data per tonne of product from installations for the manufacture of bricks

and roof tiles ...................................................................................................................... 126 Table 3.10: Maximum concentration of clean gas in the manufacture of vitrified clay pipes.................. 128 Table 3.11: Specific energy consumption in the manufacture of vitrified clay pipes .............................. 129 Table 3.12: Raw gas values of different refractory products.................................................................... 131 Table 3.13: Emissions from kilns for non-basic refractory products ....................................................... 131

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Table 3.14: Raw gas values for special procedures ..................................................................................131 Table 3.15: Energy consumption data for the manufacture of magnesia refractory bricks, regarding kg of

product ...............................................................................................................................132 Table 3.16: Ranges of dust emission values from primary crushing downstream of a fabric filter..........134 Table 3.17: Ranges of actual emission values from dry grinding downstream of the respective filter

system.................................................................................................................................134 Table 3.18: Ranges of dust emission values from granulation downstream of a fabric filter ...................135 Table 3.19: Ranges of emission values from firing processes downstream of the respective filter systems

............................................................................................................................................135 Table 3.20: Dust emission values of screening units with and without sand crusher ...............................136 Table 3.21: Operating data and raw gas values of spray drying units ......................................................137 Table 3.22: Operating data and raw gas values of dryers .........................................................................138 Table 3.23: Operating data and raw gas values in firing...........................................................................138 Table 3.24: Gaseous emissions from the various phases of wall and floor tile manufacturing processes.

Pollutant emission factors for uncontrolled (UC) and controlled (C) emissions................139 Table 3.25: Chemical analysis of untreated process waste water .............................................................139 Table 3.26: Ranges of the main chemical components of sludge (manufacture of wall and floor tiles)...140 Table 3.27: Examples of specific energy requirements of different kilns.................................................141 Table 3.28: Comparison of the specific consumption of thermal energy and electrical energy per process

step .....................................................................................................................................141 Table 3.29: Operating data and clean gas dust emission values of a spray dryer .....................................142 Table 3.30: Raw gas values and operating data in household ceramics firing..........................................142 Table 3.31: Raw and clean gas values of a one time firing process of household ceramics .....................143 Table 3.32: Ceramic pigment systems used for decoration colours..........................................................143 Table 3.33: Concentrations of heavy metals in the raw gas of decoration firing......................................144 Table 3.34: Process waste water analysis of a porcelain tableware manufacturer ....................................145 Table 3.35: Process waste water analysis of a household ceramics plant .................................................145 Table 3.36: Thermal and electrical energy consumption data of a porcelain tableware manufacturer .....146 Table 3.37: Example of raw and clean gas compositions from one tunnel kiln........................................148 Table 3.38: Raw gas concentrations of tunnel and shuttle kilns ...............................................................148 Table 3.39: Examples of clean gas concentrations of two sanitaryware plants ........................................148 Table 3.40: Pollutant concentrations in cleaned process waste water.......................................................149 Table 3.41: Operating data and throughput of different kilns...................................................................150 Table 3.42: Energy consumption data ......................................................................................................150 Table 3.43: Raw gas concentrations in the firing of electrical insulators .................................................152 Table 3.44: Flue-gas concentrations from a shuttle kiln during the firing of electrical insulators............152 Table 3.45: Concentrations in cleaned process waste water from an electrical insulator manufacturer ...153 Table 3.46: Concentrations in process waste water from an electric insulator manufacturer after

flocculation.........................................................................................................................153 Table 3.47: Concentrations in cleaned process waste water from a manufacturer of piezoceramic products

............................................................................................................................................153 Table 3.48: Energy consumption data from two electroporcelain plants..................................................154 Table 3.49: Raw material compositions for the manufacture of electroporcelain ....................................154 Table 3.50: Examples of flue-gas values from two plants in which inorganic bonded abrasives are

manufactured......................................................................................................................155 Table 3.51: Overall energy consumption data from two inorganic bonded abrasives manufacturers ......156 Table 3.52: Raw material consumption data from two inorganic bonded abrasives manufacturers.........156 Table 4.1: Information breakdown for each technique described in this chapter. ....................................157 Table 4.2: Overview on techniques for the reduction of energy consumption .........................................166 Table 4.3: Examples of temperature resistance and price of filter bags....................................................170 Table 4.4: Examples of operating data for dust removal with fabric filters..............................................171 Table 4.5: Operating and cost data for electrostatic precipitators.............................................................174 Table 4.6: Overview on techniques for the reduction of dust (particulate matter) emissions ...................175 Table 4.7: Overview on techniques for the reduction of gaseous compounds..........................................198 Table 4.8: Achievable process waste water recycling ratios in different sectors of the ceramic industry 200 Table 4.9: Overview on techniques for the reduction of process waste water (emissions and consumption)

............................................................................................................................................203 Table 4.10: Overview on techniques for the recycling/re-use of sludge...................................................206 Table 4.11: Overview on techniques for the reduction of solid process losses (solid waste) ...................209 Table 4.12: Overview on techniques for the reduction of noise ...............................................................211 Table 5.1: BAT associated emission levels for gaseous inorganic compounds from flue-gases of kiln

firing processes...................................................................................................................225

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Table 10.1: Technical data of both ESPs ................................................................................................. 244 Table 11.1: Technical data of the ESP ..................................................................................................... 250

Scope

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SCOPE

This document addresses the industrial activities specified in Section 3.5 of Annex I of Directive 96/61/EC, namely: 3.5. Installations for the manufacture of ceramic products by firing, in particular roofing tiles, bricks, refractory bricks, tiles, stoneware or porcelain, with a production capacity exceeding 75 tonnes per day, and/or with a kiln capacity exceeding 4 m and with a setting density per kiln exceeding 300 kg/m. For the purposes of this document the industrial activities falling within this description will be referred to as the ceramic industry. The various sectors of the ceramic industry encompass a wide range of raw materials and manufacturing techniques, but all involve the selection of clays or other mainly inorganic materials which are processed then dried and fired. The major sectors which are based on the ceramic products (ceramics) manufactured are as follows:

wall and floor tiles bricks and roof tiles table- and ornamentalware (household ceramics) refractory products sanitaryware technical ceramics vitrified clay pipes expanded clay aggregates inorganic bonded abrasives.

Due to the wide variety of ceramic products possible, the various ceramics sectors are summarised into two groups (coarse ceramics and fine ceramics) with reference to the application of the different types of products covering also the key environmental aspects and addressing common issues for all ceramics. Common issues for all ceramics include the raw materials, the additives, the manufacturing techniques and the product properties. The group of coarse ceramics includes the sectors bricks and roof tiles, vitrified clay pipes, refractory products and expanded clay aggregates. The group of fine ceramics includes the sectors wall and floor tiles, table- and ornamentalware, sanitaryware, technical ceramics and inorganic bonded abrasives. In addition to the basic manufacturing activities, this document covers the directly associated activities which could have an effect on emissions or pollution. Thus, this document includes activities from the preparation of raw materials to the dispatch of finished products. Certain activities are not covered, because they are not considered to be directly associated with the primary activity. For example, the quarrying of raw materials is not covered. The activities that are covered include:

selection and preparation of raw materials mainly based on clays and/or other inorganic minerals

shaping of ware usually from raw materials which are in the plastic state drying of the ware and possibly coating kiln firing to achieve vitrification subsequent treatment and packaging.

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1 GENERAL INFORMATION ON CERAMIC MANUFACTURING 1.1 Historical origins The term ceramics is derived from the Greek keramos meaning burned earth and is used to describe materials of the pottery industry. Recent research shows that the processing of clay started around 19000 BC. The oldest findings of pottery in southern Japan are dated between 8000 BC and 9000 BC. As early as 4000 BC fired bricks were used for the construction of temple towers, palaces and fortifications. More than 2000 years ago the Romans spread the technique of brick making into large parts of Europe. In Egypt, glazed ceramic plates were used as wall decorations for the pyramids in 2600 BC and in China, the art of china porcelain making has been known since 1000 BC.

1.2 Characteristics of ceramics Generally the term ceramics (ceramic products) is used for inorganic materials (with possibly some organic content), made up of non-metallic compounds and made permanent by a firing process. In addition to clay based materials, today ceramics include a multitude of products with a small fraction of clay or none at all. Ceramics can be glazed or unglazed, porous or vitrified. Firing of ceramic bodies induces time-temperature transformation of the constituent minerals, usually into a mixture of new minerals and glassy phases. Characteristic properties of ceramic products include high strength, wear resistance, long service life, chemical inertness and non-toxicity, resistance to heat and fire, (usually) electrical resistance and sometimes also a specific porosity. The main steps in the manufacture of ceramic products are largely independent of the materials used and the final product. The following figure schematically shows the typical process and possible or necessary supply and disposal facilities. The process is made up of the steps: mining/quarrying of raw materials and transport to the ceramic plant (neither of these two steps is covered in this document), storage of raw materials, preparation of raw materials, shaping, drying, surface treatment, firing and subsequent treatment [23, TWG Ceramics, 2005].

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Noise

Emissionsto air

Waste

Waste water

Firingauxiliaries

Fuels

Product

Preparation of raw

materials

Shaping

Drying

Surfacetreatment

Firing

Subsequent treatment

Watertreatment

Recycling

Flue gascleaning,dedusting

Storage offuels

Productionof moulds

Glazepreparation

Frits

Colour

Base

Electricpower

Auxiliaryagents

Rawmaterials Water

Sorptionagents

Determination of BAT

Mining of raw materials and transport to ceramic plant

Storage of raw materialsin ceramic plant

and internal transport

Re-use forraw materialspreparation

Figure 1.1: Stages in the manufacture of ceramic products

The best available techniques for integrated environmental protection in the ceramic industry named in this document are related to the processes employed within the bordered area.

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1.3 Geographical distribution and general economic considerations

Clay raw materials are widely distributed throughout Europe, so ceramic products like bricks which are relatively inexpensive (but which incur high transport costs due to their weight) are manufactured in virtually all Member States. Building traditions and heritage considerations result in different unit sizes from country to country. More specialised products which command higher prices tend to be mainly produced in a few countries, which have the necessary special raw materials and equally important traditions of skill and expertise. For example, a large percentage of ceramic tiles are manufactured in Italy and Spain; tableware in the United Kingdom, Germany and France; vitrified clay pipes in Germany, United Kingdom, Belgium and the Netherlands. There is considerable international trade in wall and floor tiles, refractory products, table- and ornamentalware, technical ceramics, vitrified clay pipes and sanitaryware. The importance of the ceramic industry in terms of employment and economics is shown in the following table [20, CERAME-UNIE, 2004] [23, TWG Ceramics, 2005] [26, UBA, 2005].

Sector of Ceramic industry Output 2000 (x million tonnes)

EU-15 sales 2003(x million EUR)

Manpower 2003(x 1000)

Wall and floor tiles 25.0 10100 69 Bricks and roof tiles 55.0 6800 50 Table- and ornamentalware 0.5 2000 48 Refractory products 4.5 3100 18 Sanitaryware 0.5 1900 25 Technical ceramics 0.15 2000 9 Vitrified clay pipes 0.5 300 3 Expanded clay aggregates (2002) approx. 2.0 170 1.1 Inorganic bonded abrasives ? ? ?

Table 1.1: Ceramics output, sales and employment figures

1.4 Key environmental issues Depending on the specific production processes, plants making ceramic products cause emissions to be released into air, water and land (waste). Additionally, the environment can be affected by noise and unpleasant smells. The type and quantity of air pollution, wastes and waste water depend on different parameters. These parameters are, e.g. the raw materials used, the auxiliary agents employed, the fuels used and the production methods:

emissions to air: particulate matter/dust can arise from the handling or processing of

raw materials or product finishing and also soot can arise from firing fuel oil. Gaseous emissions arise during the firing or spray-drying of ceramics and may be derived from the raw materials and/or from the fuels employed. Carbon oxides, nitrogen oxides, sulphur oxides, inorganic fluorine and chlorine compounds, as well as organic compounds are of particular importance among the gaseous emissions. Due to the use of substances for decorative purposes which contain heavy metals, or due to the usage of heavy oil as fuel, heavy metals can also be emitted

emissions to water: these mainly occur during the manufacturing processes of ceramic

products and the resulting process waste water mainly contains mineral components (insoluble particulate matter). Depending on the production method, the process waste water also contains further inorganic materials, small quantities of numerous organic materials as well as some heavy metals. Apart from process waste water, which often is cleaned and re-used in closed circuits, also cooling water, rainwater and sanitary waste water occur in the plant

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process losses (waste): process losses originating from the manufacture of ceramic products, mainly consist of the following materials:

o different kinds of sludge (sludge from process waste water treatment, glazing

sludge, plaster sludge, grinding sludge) o broken ware from shaping, drying, firing and refractory material o dust from flue-gas cleaning and dedusting units o used plaster moulds o used sorption agents (granular limestone, limestone dust) o packaging waste (plastic, wood, metal, paper, etc.).

Parts of the accumulated process losses mentioned above, can be recycled and re-used within the plant due to product specifications or process requirements. Materials, which cannot be recycled internally, leave the plant as waste and are supplied to external recycling or disposal facilities.

energy consumption/CO2 emissions: all sectors of the ceramic indust