Cement is a mixture of so many compounds roasted in rotary kiln. Which substances has greater percentage ?
Correct answer: A. Lime (CaO)
- A. Lime (CaO)
- B. Silica (SiO2)
- C. Alumina (Al2O3)
- D. Magnesia (MgO)
Explanation
Calcium oxide is the major oxide in ordinary Portland cement because limestone is the largest part of the raw mix and decomposes to CaO on heating. Silica, alumina and magnesia are present in smaller percentages. Students may choose silica because it forms important silicate compounds, but importance of a compound is not the same as having the greatest percentage.
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