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Portland cement clinker was first made (in 1825) in a modified form of the traditional static lime kiln. [2] [3] [4] The basic, egg-cup shaped lime kiln was provided with a conical or beehive shaped extension to increase draught and thus obtain the higher temperature needed to make cement clinker.
Portland cement clinker is made by heating, in a cement kiln, a mixture of raw materials to a calcining temperature of above 600 °C (1,112 °F) and then a fusion temperature, which is about 1,450 °C (2,640 °F) for modern cements, to sinter the materials into clinker.
Cement chemist notation (CCN) was developed to simplify the formulas cement chemists use on a daily basis. It is a shorthand way of writing the chemical formula of oxides of calcium , silicon , and various metals .
Portland cement clinker is made by heating a homogeneous mixture of raw materials in a rotary kiln at high temperature. The products of the chemical reaction aggregate together at their sintering temperature, about 1,450 °C (2,640 °F).
It requires a much lower content in colored impurities in the raw materials (essentially limestone and clay) used to produce clinker: low levels of Cr 2 O 3, Mn 2 O 3, and Fe 2 O 3), but above all, a higher temperature is needed for the final sintering step in the cement kiln (1600 to 1700 °C in place of 1450 °C for ordinary Portland cement ...
Fluorine is beneficial to the kiln process in that it allows alite to form at lower temperature. However, at levels above 0.25% in the clinker, delayed and erratic cement setting time results. Alkali metals (primarily sodium and potassium) cause processing problems because they form volatile salts in the kiln system. These evaporate in the kiln ...
LOI is also used in the cement industry which operates the furnace in the 950 °C range (e.g. cement kilns), combustion engineers also use LOI but at temperatures lower than 950 °C range. [ 7 ] Safety
Ordinary Portland cement requires a kiln temperature of around 1450 °C. The reactive magnesia in Eco-Cement requires a lower kiln temperature of 750 °C, [1] which lowers the energy requirements, and hence the use of fossil fuels and emission of carbon dioxide (CO 2).