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Calcined alumina in ceramic tiles

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Use of alumina ceramic coatings

Calcined and fused aluminas in ceramic tiles are used to confer both resistance to abrasion and resistance to chemical attack and also give the opacification effect . For this reason, alumina is used in compositions of engobes, glazes and inks.

In its use in glazing, alumina has a wide range of functions it can be used to ensure the increase of the PEI coating to generate optical effects semi-gloss, matte, fusibility and control the expansion of the glaze. The addition of alumina can be given either in the grinding of raw materials or in the dispersion of the glaze / correction phase characteristics.

The final effect of the alumina addition depends on its physicochemical characteristics. There are different types of calcined aluminas, each of which is produced by a different type of processing. Thus, the microstructural aluminas have physical differences, which give different behaviors in the preparation and firing of the glaze process.

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Calcined alumina in ceramic tiles

  1. 1. USE OF ALUMINA IN THE CERAMIC TILES INDUSTRY Marcelo Suster FORN&CER- 2014 7ª. Edição
  2. 2. Global Presence High alumina balls Mill liners Zirconite Calcined aluminas Itaforte Materiais de Alta Performance Telefone: +55 19 3023-5995/ 3023-9241 |
  3. 3. Hindalco produces Calcined Alumina Hydrate and with different levels of sodium and par9cle size distribu9ons. OP1 Low grade calcined alumina S3 High grade calcined alumina S3G High grade calcined alumina-­‐ ground (-­‐ 325mesh). S5 High grade calcined alumina with low soda S5G High grade calcined alumina with low soda content and ground (325mesh). H10 Dry hydrate. H10G Ground or jet milled dry hydrate. HU Wet hydrate
  4. 4. Zirconite -­‐ Zirconium Silicate The Kreutz Zirconium Silicates are used in Ceramic Tiles, Glass, Ceramics and others. ! Griding media and mill 9les ITAFORTE China produces high performance ball and is the exclusive representative of German Kreutz.
  5. 5. Raw Materials • Naturals – plastics – Non plastics • Sinthetics – Non plastics
  6. 6. Alumina Sources Raw Materials Feldspar Kaolin Bauxite Minerals Feldspar and caulinitics Sands Naturals & Nefeline-Sianite Stones Quartz sands (as impurities) Fonolite Basalt Granite Agalmatolite Calcined Alumina Al2O3 Hydrate Al(OH)3 Chemical Products Aluminum Nitrate Al(NO3)3 Sintethics Aluminum Sulphate Al2(SO4)3 By products Blast furnace slag Source: Elaborated by Author
  7. 7. Bauxite Mine Alumina Trihydrate Calcined Alumina Primary Aluminum Smelter Zeolites and Desiccants Paints, Paper Adhesives, Rubber Fillers & Coatings Wallpaper, Waxes Ink, Paint, Paper, Rubber Synthetic Rubies, Sapphires Cutting Tools Polishing Compounds Glass, ceramics Refractories White, Pink and Ruby Fused Abrasive Grains Chemical Industry Crude White, Pink Ruby Fused Alumina Detergent Zeolites Toothpaste Cosmetics Farmaceuticals Deodorants Antacids Flame Retardant Carpet Backing Foam & Solid Plastics Plastic Wire Insulation Wallboard Petroleum Refining Catalyst Support, auto Exhaust Activated Alumina Claus Process Sulfur Recovery Adsorbent for gases, liquids Desiccants Low Soda Alumina Whiteware, fine China Porcelain Insulators Kiln Furniture Pigments High Purity Alumina Substrates: Microchips, Catalysts Translucent Alumina Products Welding Electrode Coating Fillers & Coatings Epoxy, silicone, Polyester Catalyst Support AbrasiveBs eds Chorides Fluoride Sulfate Aluminate FCC (fluid cracking catalysts) Molecular sieves Hydroteating catalysts Fused minerals Calcined Al Sulfate Source: Elaborated by Author
  8. 8. Aluminas Caracteristhics Low Medium High Fused Calcination grade Calcination temp. (°C) 1,000 1,100 1,250 2,200 Surface area (m 2 /g) 45-75 9-11 0.9-1.4 0.7-0.9 Alpha phase content (%) <5 <10 >96 >99 Primary cristal size ( μ m ) <0.01 <0.1 3-4 1,000-3,000 Source: Elaborated by Author
  9. 9. Productive process Calcined Alumina • Bayer Process  Bauxite  Digestion  Extraction  Precipitation  Calcination Source: Elaborated by Author
  10. 10. Productive process Fused Alumina (corundun) • Electrofusion  Calcined alumina – High surface area  Melting  Crushing  Sieving  Milling Higgins Furnace Source: Elaborated by Author
  11. 11. Aluminas- Morfology Low Calcination High Calcination Fused Source: Elaborated by Author
  12. 12. Application of Alumina in Ceramic Tiles Glaze (Frits) Engobe Base Anti-slipping Ink Source: Elaborated by Author
  13. 13. Aluminas Light Effects Alumina Type-calcination grade/ electrofusion Surface Area m2/g Crystal Size μm Effect Low calcination 50-300 0,01-0,1 highly opacifier Medium Calcination 8-15 0,1-1,0 semi-matizante High Calcination 1-3 1-5 semi-bright Fused 1 100-5000 Bright Source: Elaborated by Author
  14. 14. Trends • Valuation of the ceramic tiles • Aesthetics • Thermal Comfort • Hygiene • Multitude of uses • facades • living rooms • dorms • National standard of decor • liberation of Europe • international competitiveness
  15. 15. Challenges Shelf life & Beauty • Abrasive Wear • Chemical attack • Textural • Chipping/cracks • Swelling
  16. 16. Reformulation of engobes Aiming Replacement Zirconita Paulo Sérgio Gonçalves, Marcelo Suster e Ronaldo dos Santos Flor Cerâmica Industrial- Volume 5 - Número 1 - Janeiro/Fevereiro - 2000 Raw materials Formulatio n standard engobe (%) Formulation of partial substitution with engobe alumina (%) Properties Standart with alumina Clay Caulinítica (%) 30 27 Opacity grade OK OK Feldspar Ortoclásio (%) 25 25 Impermeability grade OK OK Zirconite # 500 (%) 20 5 dilation °C –1 X 10-7 65 64 White Frits - Zr cs533 (%) 20 25 Reology/ outflow time (s) Cop for-4 12 12 Koalin (%) 5 12 Alumina (%) - 6,0 Quartz - - Carboxi Metil Celulose (CMC) 0,3 0,3 Tripolifosfa to de Sodium (TPF) 0,1 0,1 Source: Elaborated by Author
  17. 17. Frits (glass) Al 3+- Network Stabilizer Al3+ Source: Elaborated by Author
  18. 18. Effects of adding alumina FRITA MATE DE ZINCO BRILHO ALVURA ABRASÃO 100 80 60 40 20 0 -20 Valores relativos Propriedades ALTA MÉDIA BAIXA CÓRINDOM Source: Elaborated by Author
  19. 19. Alumina Properties  Fusibility Bubles Alumina Al2O3 - SiO2 - MgO - ZrO2 - CaO - ZnO - PbO - B2O3 - Na2O - K2O Source: Elaborated by Author
  20. 20.  Viscosity Alumina Properties 1260 1280 1300 1320 1340 1360 1380 1400 1200 1000 800 600 400 200 0 Albita Ortoclásio Viscosidade (cP) Temperatura (oC) B2O3 - Na2O - K2O - PbO - ZnO - MgO - CaO - SiO2 - ZrO2 - Al2O3 Source: Elaborated by Author
  21. 21. Alumina Properties  Surface tension Furo PbO - B2O3 - K2O - Na2O - BaO -CaO - ZnO - ZrO2 - Al2O3 - MgO Source: Elaborated by Author
  22. 22. Conclusion The aluminum oxide is present in virtually all ceramic products, and its presentation as a pure element is particularly important in the ceramic tile industry, either in the manufacture of glazed, engobes, chips, stains, anti-slip coatings as well as in inputs for grinding. Checking all these applications its high mechanical properties superior abrasion resistance and chemical attack.
  23. 23. Thank you!!! ms@itaforte.com

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