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How to Calculate Clinker Phases

Heating limestone and clay together at around 1,450 degrees Celsius produces Portland cement clinker. It is a gray, rocky material cement producers grind up into a fine powder to make cement. The heating process causes oxygen to combine with the minerals in the clinker to form several oxides. Chemical analysis can determine what percentage, by weight, each of the oxides represents in the clinker. Based on those numbers, the Bogue calculation determines the approximate proportions of the four main minerals in the clinker: alite (C3S), belite (C2S), aluminate phase (C3A) and ferrite phase (C4AF).

Things You'll Need

Weight percentage of SiO2, silicon dioxide
Weight percentage of Al2O2, aluminum dioxide
Weight percentage of Fe2O3, ferrous trioxide
Weight percentage of CaO, calcium oxide

Instructions

- 1
  Subtract one percent from the CaO to account for lime that did not melt into the clinker. For example, 66.6 percent CaO becomes 65.6 percent CaO.
- 2
  Calculate the alite according to this formula: 4.0710 * CaO minus 7.6024 * SiO2 minus 1.4297 * Fe2O3 minus 6.7187 * Al2O3. With 65.6 percent CaO, 21.5 percent SiO2, 2.8 percent Fe2O3 and 5.2 percent Al2O3, the amount of clinker in the C3S phase turns out to be 64.7 percent.
- 3
  Calculate the belite according to this formula: 8.6024 * SiO2 plus 1.1 * Fe2O3 plus 5.0683 * Al2O3 minus 3.0710 * CaO. With the same numbers from above, the result is 12.9 percent of the clinker is in the belite phase.
- 4
  Calculate the aluminate phase according to this formula: 2.6504 * Al2O3 minus 1.6920 * Fe2O3. With the same weight percentages, the C3A content is 9 percent.
- 5
  Calculate the ferrite phase, lastly, by multiplying 3.0432 by the Fe2O3 oxide weight percentage. Therefore, 3.0432 times 2.8 yields a ferrite phase content of 8.5 percent.

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