The firing temperature must be large enough for the formation of the Alite(C3S) phase. Burning of raw-mix is generally carried out at 1450°C – 1500°C.
An excessively high burning temperature results in
- High stress on the kiln
- Failure of the refractory lining,
- High fuel consumption,
- Reduction in cement strength (due to larger C3S crystals).
An increase in burning temperature from 1360°C to 1420°C results in lowering the burning period by half. Maximum firing temperature was determined by a multiple regression analysis of raw meal containing only the four main oxides The theoretical temperature for clinker burning is given as
