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Cement Production

Cement Production. Portland Cement. By definition — a hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an interground addition. Source: PCA, 2003.

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Cement Production

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  1. Cement Production

  2. Portland Cement By definition — a hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an interground addition

  3. Source: PCA, 2003

  4. Raw Materials Necessary for Portland Cement Manufacture Must Provide the Following • Calcium • Silica • Alumina • Iron

  5. Source: PCA, 2003

  6. Traditional Manufacture of Portland Cement 1. Stone is first reduced to 125 mm (5 in.) size, then to 20 mm (3/4 in.), and stored. Source: PCA, 2003

  7. Raw materials are ground to powder and blended. or 2. Raw materials are ground, mixed with water to form slurry, and blended. Source: PCA, 2003

  8. 3. Burning changes raw mix chemically into cement clinker. Source: PCA, 2003

  9. Source: Mindess, Young, and Darwin, 2004

  10. Source: Mindess, Young, & Darwin, 2004

  11. 3. Burning changes raw mix chemically into clinker. Note four stage preheater, flash furnaces, and shorter kiln. Source: PCA, 2003

  12. Pyro- Processing

  13. Source: PCA, 2003

  14. 4. Clinker is ground with gypsum into portland cement and shipped. Source: PCA, 2003

  15. Clinker Gypsum Source: PCA, 2003

  16. Grinding • Clinker is ground with gypsum (calcium sulfate) to produce portland cement • Fine grinding is necessary for high early strength • 85-95% -325 mesh (45 microns) • ~ 7 trillion particles per pound • Gypsum absorbs water and prevents setting of C3A during shipment

  17. Source: van Oss and Padovani, 2002

  18. Process of Clinker Production Source: PCA, 2003

  19. Source: PCA, 2003

  20. Source: PCA, 2003

  21. Source: Taylor, 1997

  22. Source: MacLaren and White, 2003

  23. Source: MacLaren and White, 2003

  24. Clinker Phases • Alite or 3CaO•SiO2or C3S • Hydrates & hardens quickly • High early strength • Higher heat of hydration (setting) • Belite or 2CaO• SiO2or C2S • Hydrates & hardens slower than alite • Gives off less heat • High late strength (> 7 days) • Modern cements are manufactured to be higher in alite for early strength

  25. Clinker Phases • Aluminate or 3CaO• Al2O3or C3A • Very high heat of hydration • Some contribution to early strength • Low C3A for sulfate resistance • Ferriteor4CaO• Al2O3 • Fe2O3orC4AF • Little contribution to strength • Lowers clinkering temperature • Controls the color of cement

  26. Microscopic Images of Clinker

  27. Microscopic Images of Clinker Alite

  28. Microscopic Images of Clinker Belite

  29. Microscopic Images of Clinker Aluminate

  30. Microscopic Images of Clinker Ferrite

  31. Types of Portland Cement ASTM C 150 (AASHTO M 85) I Normal II Moderate sulfate resistance III High early strength IV Low heat of hydration V High sulfate resistance

  32. Source: Mindess, Young, and Darwin, 2004

  33. Source: Mindess, Young, and Darwin, 2004

  34. Source: Mindess, Young, and Darwin, 2004

  35. Source: Mindess, Young, and Darwin, 2004

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